BD 099 200 AUTHOR TITLE INSTITUTION SPONS AGENCY PUB DATE NOTE EDRS PRICE DESCRIPTORS IDENTIFIERS DOCUMENT RESUME SE 017 350 McDermott, John J., Ed. The Enviornmental Impact of Electrical Power Generation: Nuclear and Fossil. A Minicourse for Secondary Schools and Adult Education. Text. Pennsylvania State Dept. of Education, Harrisburg. Bureau of Curriculum Services. Atomic Energy Commission, Oak Ridge, Tenn. Div, of Nuclear Education and Training. 73 97p.; For the teacher's guide, see SE 017 349 MF-$0.75 HC-$4.20 PLUS POSTAGE Adult Education; Conservation Education; Economics; *Energy; *Environmental Education; Environmental Influences; Fuels; *Instructional Materials; Interdisciplinary Approach; *Natural Resources; Pollution; Science Education; *Secondary Grades Atomic Energy; *Electric Power Generation; Nuclear Energy ABSTRACT This course, developed for use in secondary and adult education, is an effort to describe the cost-benefit ratio of the various methods of generation of electrical power in an era when the requirement for additional sources of power is growing at an ever-increasing rate and environmental protection is a major concern. This course was written and compiled by an independent committee drawn, from educators, engineers, health physicists, members of industry and conservation groups, and environmental scientists. Among the topics discussed are the increasing need for electrical power and methods for meeting this need, nuclear power and fossil fueled plants, the biological effects of nuclear and fossil fueled plants, wastes in the production of electric power, plant site considerations, energy conservation, and the environmental effects of electrical power generation. The appendixes include a glossary of terms, a bibliography, a decision-making model and a brief outline of the procedures which must be followed by a utility in order to construct and operate a nuclear power plant. (BT)
Transcript
BD 099 200
AUTHORTITLE
INSTITUTION
SPONS AGENCY
PUB DATENOTE
EDRS PRICEDESCRIPTORS
IDENTIFIERS
DOCUMENT RESUME
SE 017 350
McDermott, John J., Ed.The Enviornmental Impact of Electrical PowerGeneration: Nuclear and Fossil. A Minicourse forSecondary Schools and Adult Education. Text.Pennsylvania State Dept. of Education, Harrisburg.Bureau of Curriculum Services.Atomic Energy Commission, Oak Ridge, Tenn. Div, ofNuclear Education and Training.7397p.; For the teacher's guide, see SE 017 349
ABSTRACTThis course, developed for use in secondary and adult
education, is an effort to describe the cost-benefit ratio of thevarious methods of generation of electrical power in an era when therequirement for additional sources of power is growing at anever-increasing rate and environmental protection is a major concern.This course was written and compiled by an independent committeedrawn, from educators, engineers, health physicists, members ofindustry and conservation groups, and environmental scientists. Amongthe topics discussed are the increasing need for electrical power andmethods for meeting this need, nuclear power and fossil fueledplants, the biological effects of nuclear and fossil fueled plants,wastes in the production of electric power, plant siteconsiderations, energy conservation, and the environmental effects ofelectrical power generation. The appendixes include a glossary ofterms, a bibliography, a decision-making model and a brief outline ofthe procedures which must be followed by a utility in order toconstruct and operate a nuclear power plant. (BT)
4
POE WORKING PAPER
TheEnvironmental Impact
ofElectrical Power Generation:
Nuclear and FossilA Minicourse forSecondary Schools
andAdult Education
Division of Science and TechnologyBureau of rThrriculum ServicesPennsylvania Department of Education1973
U S DEPARTMENT OF HEALTH.EDUCATION & WELFARENATIONAL INSTITUTE OF
EDUCATIONOnt MI N HA. III I N wf iiqi)
.c I n f xt.( T, 41 (1 .../1 C) I ICONI III 11 k %ON (-Le :1I .AN 014'('NA!:Nf.I P(1.N, . ; t A 114
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4
Commonwealth of PennsylvaniaMilton J. Shapp, Governor
Department of EducationJohn C. Pittenger, Secretary
Office of Basic EducationDonald M. Carroll Jr., CommissionerHarry K. Gerlach, Deputy Commissioner
Bureau of Curriculum ServicesPauline M. Leet, Director
Division of Science and TechnologyIrvin T. Edgar, ChiefJohn J. McDermott
Senior Program Adviser, Science
Pennsylvania Department of Education
Box 911
Harrisburg, Pa. 17126
ii
PURPOSE OF COURSE
In an era when the requirement for additional sources of power is growing at anever-increasing rate, and concern for the protection of our environment is rightfully comingto the fore, it is imperative that an unbiased, straightforward, and objective view of theadvantages and disadvantages of the nuclear generation of electrical power be made availableto our schools.
The development of this minicourse has been partially supported by the Divisionof Nuclear Education and Training of the U.S. Atomic Energy Commission and producedunder the direction of the Pennsylvania Department of Education. It was written andcompiled by an independent committee drawn from educators, engineers, health physicists,members of industry and conservation groups, and environmental scientists.
This course is an effort t' describe the cost-benefit ratio of the various methodsof generation of electrical power.
John J. McDermott, Project Directorand Editor
Janet Fay Jester, Technical WriterCharles Been lerWilliam H. BollesRobert H. CarrollIrvin T. EdgarAlan H. GeyerGeorge L. JacksonWillard T. JohnsWilliam A. JesterRichard LaneJames Mc QueerFrank B. PillingMargaret A. ReillyRobert W. SchwilleMichael SzaboJohn D. VoytkoDaniel WelkerWarren F. WitzigHarold H. Young
Committee
Pennsylvania Department of Education
Rosetree Media School DistrictPennsylvania Department of EducationPennsylvania Department of EducationPennsylvania Department of EducationPennsylvania Topographic and Geologic SurveyHarrisburg Hospital, Division of Nuclear MedicinePennsylvania Fish CommissimThe Pennsylvania State UniversityU. S. Environmental Protection AgencyTitusville Are School DistrictSierra ClubPennsylvania Office of Radiological HealthPennsylvania Department of EducationThe Pennsylvania State UniversityWestinghouse Environmental SystemsNorth Schuylkill School DistrictThe Pennsylvania State UniversityU. S. Atomic Energy Commission
INTRODUCTION
Chapters 1 aid 2 of this text present the increasing need for electrical power, and current and proposedmethods for meeting this necd. Expansion of electrical generating capacity in the immediate future will belimited to nuclear power plants or fossil fueled plants. These plants are discussed in Chapters 3 and 4. Butthese plants have an impact on our environment. The biological effects of nuclear and fossil fueled plants
are discussed in Chaptt 5. In addition to having biological effects, these plants produce wastes, including
waste heat, that have environmental effects. These wastes are the subject of Chapter 6. Chapter 7 presents
some of the factors that must be taken into cohsideration when choosing the site for a new power plant.
In addition to increasing electrical power generating capacity, we must begin to conserve the energy sourceswe have. Thus energy conservation is the subject of Chapter 8. Finally, a summary of environmental effects
is given.
Appendix I is a glossary of useful terms, many of which are used in the text. When one o. the words
in the glossary is used for the first time in the text, it appears in italics. Appendix II is a bibliographycontaining many useful references for future study. Appendix III is a decision-making model to help the
reader analyze the information he has receives Appendix IV is a brief outline or the procedures which must
be followed by a utility in order to construct and operate a nuclear power plant.
ii
THE WORLD'S ENERGY PRODUCTION
NUCLEAR
NATURAL GAS
OIL
SYNTHETICS
COAL
GEOTHERMAL.....1 HYDROEL ECTRIC
v r t r li WOOD
1850 191'0 1950 '70 '85 2000
TABLE OF CONTENTS
Page
Chapter 1. The Demand for Electrical Energy 1
Chapter 2. Meeting the Demand for Electrical energy
Chapter 6. Wastes in the Production of Electric Power 49
Chapter 7. Plant Site Considerations 54
Chapter 8. Energy Conservation: The Need for More Efficient Use if Energy 59
Appendix I Glossary of Terms 62
Appendix II Bibliography 89
Appendix III A Decision Making Model 93
Appnuix IV Licensing of Nuclear Power Plants 96
LIST OF ILLUSTRATIONS
Page
The World's Energy Production iii
Energy Consumption and Living Standards 2
Production of Electricity 6
Major Steam Generating Stations: 1970 7
Major Steam Generating Stations: J 990 8
Nuclear Fission Chain Reaction 15
Uranium Fission and Beta Decay Chains 16
Schematic Arrangement of Boiling Water Reactor 18
Fuel Assembly 19
Cutaway of Fuel Element (cm Nuclear Reactor Core.... 20
Boiling Water Reactor 21
Pressurized Water Reactor 23
High Temperature Gas Cooled Reactor 24
Liquid Metal Fast Breeder Reactor 26
Conventional Fossil - Fueled Plant 30
Coal Fields of the United States 32
Ionization by Charged Particles 35
What are Isotopes ? 38
Offshore Nuclear Power Plant 57
Flowchart of Basic Decision - Making Model forReso! .tion of Environmental Problems 87
Chapter
THE DEMAND FOR
Energy, the power to do work. is the basicbuilding block of civilization. The standard of livingof people throughout time has been directlydependent upon their energy resources. Figure 1
shows the relationship between energy consumptionand living standards for many different countries.
It becomes obvious from looking at Figure 1that Americans have a gluttonous appetite for energy.In the past, we have tended to act as though ourenergy-producing resources such as coal, gas and oilwere unlimited. Now, however, we are beginning torealize that they are not. We hear about the shortageof natural gas, fuel oil and gasoline. We hear aboutor even experience "black-outs" or "brownouts"from a shortage of electricty. We are also recognizingthe impact on the environment resulting from thelarge-scale production of energy.
Thus, in the past several years, the words"energ: crisis" have been increasingly heard. Onemajor thrust of this crisis concerns the conversionof various fuels such as coal, gas. oil or uranium intoelectrical energy.
The United States, with :bout six per cent ofthe world's population, consumes about 35 per centof the world's yearly electrical energy. According tothe New York Times, every child born in the UnitedStates will use eight times as much of the world'snatural resources as a child born in anunderdeveloped country.
The demand for electricity in this country hasbeen doubling every 10 years. One reason for thisincreased demand has been the growing population.
Population growth is not new to American life.Big families are rooted in our frontier traditionourearly years of rapid growth westwardwhen familiesof seven or eight children were necessary for someto survive in a harsh and forbidding e.mironment.With the closing of the frontier, American familiesbecame smaller, and durin3 the Depression years, thepopulation actually began to decline. FollowingWorld War Ii, the size of the American family againincreased significantly. At present, our population isstill increasing. but the rate of increase is smaller thanin previous years. Population projections estimatethat the population of the United States in themid-1970s will be 206 million and by 2040 will havedoubled to 412 million.
I
ELECTRICAL ENERGY
Only one-seventh of the projected increase inelectrical production in the United States will be dueto this population increase. Most of the remainderwill be due to new consumer products, industrialprocesses and improved transportation dem. ed bythe American public to maintain an ever-increasingstandard cf living. Do members of your family ownmore electrical appliances than they did five yearsago? Chances are good that they do and this use ofelectricity in the home represents only part of anindividual's per capita cunsumption of electricity.Much more electricity is expended to manufacturethe goods and services required to maintain thedesired standard of living. Most of the manufactureditems which Americans take for granted, such asplastics, aluminum and glass, are made with theexpenditure of electrical energy. In fact, the nationhas become so dependent on electrical power andother forms of mechanical energy that human musclenow accounts for less than one per cent of the workdone in factories.
In addition to these increasing demands forelectricity, significant amounts will soon be requiredfor purposes related to cleaning up the environment,such as recycling of wastes, mass transit and sewagetreatment.
Table 1 presents a breakdown of the uses ofelectricity.
Table 1
Consumption of Electricity in the United States
Use Percentage US.Average
Residential 32%
Commercial 22%
Industrial 42%
Other Uses 4%
I
BEST r
5030
4000
3000
2000
1000
I CO
'TEA KINGpim
ERLANDS
AN ADA
2000 4000 6000 1,000 10,000 12,000
ENERGY CONSUMPTION
(KILOGRAMS OF COAL EQUIVALENT PER CAPITA)
FIGURE I
ENERGY CONSUMPTION AND LIVING STANDARDS
2
Student Activity: Mei much electricity do you use?
1. Make a list of the electrical appliances in yourhome. Do not forget such Items as electric furnacefans, light bulbs, air conditioners, kitchen appliances,hair driers, etc.
2. From Table 2, write the annual kilowatt hour(KWH) consumption beside each entry on your list.
3. Add these for the total annual kilowatt hourconsumption for your family.
4. Divide this total by the number of persons inyour family to arrive at your per capita annualkilowatt hour consumption.
Table 2
Electrical Consumption for Some Common HomeAppliances
If you know the amperage rating of anyappliance, you can estimate the kilowatt hourconsumption by using the formula
KWH = Amps x volts* x hours of ase1000
*Use 110 or 220 volts, whichever applies.
Now that you have estimated the annualelectrical consumption for your family, keep in mindthat this represents only part of your real per capitaconsumption. Much more electricity is expended tomanufacture the goods and services you use each day.The per capita electrical consumption in the UnitedStates for the year 1968 was 6500 kilowatt hours,most of it for industrial processes to maintain ourhigh standard of living.
Table 3 gives past data and projections compiledby the electric utility industry for population andpower needs.
Table 3
Population Projections and Power Needs1540 1970 1980 2000
U.S. Population(millions) 142 200 232 301
Total Power Capacity(millions of kilowatts) 85 340 665 21000
Power Consumed perperson pct. year(kilowatt hours) 2000 7000 13000 33000
4
The projected growth of generating capacity in11 Northeastern states illustrates these rapidlymounting electrical power demands. A report to theFederal Power Commission indicates that between1970 and 1990, the power industry in these 1! stateswould have to build about four times r muchelectrical generating capacity as the industry hadprovided in all its 80-year history. In other words,about four times the 1970 capacity must be builtin one-fourth the time to meet the projected needs.Based on 1970 prices. these tremendous undertakingswill involve an investment of a staggering $50 billionfor generation, transmission, and distributionfacilities.
a
Chapter 2
MEETING THE DEMAND FOR ELECTRICAL
THE GENERATION OF ELECTRICAL ENERGY
Our idea of electricity is based largely on whatit does, its effects, rather than on what it is. We lookupon electricity as something that makes light bulbsglow, or irons get hot, or refrigerators get cold. Butwhat is electricity?
Electricity, that is, an electric current, is theflow of electrons in a conductor. An electron is avery, very small negatively charged subatomicparticle. A concluder is a material which has freeelectrons that can be moved through it easily. Amongthe materials most familiar to us, metals are the bestconductors of electricity.
The production of an electric current is fairlysimple. All that is required is to make electrons runthrough a conductor. A loop of wire, preferablycopper wire, can be the conductor. This wireconductor is loaded with free electrons. Since thesefree electrons are negatively charged, they will reactto a magnet. If the conductor wire is formed *.rfra loop and the loop is moved through the magn ticfield which exists between the north (N) and south(S) poles of a magnet, an electric current will flowthrough the loop. Figure 2 shows a loop being pulledfrom right to left through the magnetic field linesof force (dotted lines) which cause an electric current(1 to flow in the clockwise direction shown by thearrows. The free electrons actually flow in theopposite direction from the electric current.
If the conductor loop is spun between the polesof the magnet, the electrons in the loop will moveback and forth within the loop. As the loop passesback and forth through the magnetic field lines offorce, the current is made to flow first in onedirection and then in the reverse direction. (Figure3) Current produced in this way is called alternatingcurrent (a.c.) because the electrons and therefore thecurrent are moving in alternating directions in theconductor. This is the kind of current we use everytime we plug something into an electrical outlet.
The largest electric power generator makeselectricity in the same way. by moving loops ofconducting wire between the poles of magnets. Ofcourse, a large plant uses miles and miles of Vre in
5
ENERGY
the loops and enormous magnets, but the sameprinciples are used.
The only real difference in the many types ofelectrical generating plants is the method used tomove the conductor wires in the magnetic field. Inmost types of plants, some type of fuel such as coal,oil or uranium is used as an energy source to makesteam. This steam then pushes on the blades of aturbine so that the turbine spins. The conductorloops are attached to the spinning turbine, so thatthey spin between the poles of huge magnets. Anyplant that uses steam to spin the turbine is calleda steam generator, or steam electric station.
The hydroelectric station is different from thesteam electric station. The hydroelectric station usesfalling water to make the turbine spin. Gas turbinesuse hot gases to spin the turbine, much like a jetengine.
Figure 4 shows the major United States steamgenerating centers as of 1970, by size and geographicdistribution. Figure 5 shows the projected steamgenerating need for 1990. It should be noted thatthe major power expansion will occur in the easternand far western sections of the nation.
CURRENT METHODS OF GENERATINGELECTRICAL ENERGY
The turbines that supply our electrical energywere kept spinning by these sources in 1972.
Table 4
Methods of Electrical Generation in 1972
Coal 47%
Gas 23%
Oil 10%
Hydroelectric 17%
Nuclear (Uranium) 3%
BEST Cer7 pz:Itifiqt,
FIGURE 2
A loop being pulled through the magnetic field lines of force(dotted lines) which cause an electric current to flow.
FIGURE 3
As a conductor loop passes hack and forth through the magnetic linesof force an alternating current is produced.
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Other sources such as solar energy and geothermalenergy provide a minute amount of electrical energy.
Why can't we just build more of these kindsof plants to satisfy our growing demands forelectricity?
As far as hydroelectric stations are concerned,essentially all the economic dam sites are already inuse in the United States. Remaining new sites arein remote areas away from the electrical demand.Developing these sites would have potentially adverseeffects on increasingly scarce wilderness areas.Hydroelectric plants. unlike steam generating plants,produce no waste heat, but the effect of the highdams on fist cry resources in many rivers has generallybeen detrimental.
Thus the major expansion of electricalgenerating capabilities utilizing current technologymust involve fossil fueled plants (those using coal,gas and oil) and nuclear plants. These are the twoalternatives presented and compared in detail insubsequent chapters of this text.
Before beginning this comparison, however, alook into various other possibilities for electricalgeneration is in order. This discussion is includedbecause coal, oil and gas are nonrenewable naturalresources. We will deplete our supplies in theforeseeable future. and we must develop improvedways to extend and supplement these naturalresources. Even our known reserves of high-gradeuranium ores are limited. It is expected that breederreactors. which produce mare fissionable materialthan they consume, will offset any uranium shortagefor many hundreds of years. However, the technologyto develop efficient breeder reactors is only nowreaching the pilot plant stages, and only the firstgeneration of these reactors has been built. Coalgasification will someday be used to turn our vastreserves of dirty coal into clean methane gas whichwill meet much of our future power needs. Thesefuture hopes will be covered in more detail insubsequent chapters.
Table 5 gives an estimate of when the differenttypes of fuel will be depleted.
Table 5
Estimated Depletion of Economically RecoverableWorld Fuel Reserves
9
Fuel
Mineable Coal
Oil
Gas
Year
2400
2030
2020
Fissionable Uranium-235(High-grade ore) 2040
Uranium-238 and Thorium-232for Breeder Reactors 4000
ALTERNATIVE METHODS OF POWERPRODUCTION
The following is a summary of several possiblemethods of power production under study or inlimited use.
Fossil Fuel Sources and Energy Systems
Solvent Refining of Coal
A technique is in the development stage whichwill purify coal. Pulverized raw coal is mixed withan aromatic solvent and reacted with hydrogen gasat high temperatures and pressures. This dissolves thecoal and separates it from its ash, sulfur, oxygen andwater. The solvent is then removed, leaving apitch-like product low in sulfur and ash and with aheat content improved by as much as 60 per cent.This process will probably add significantly to thefinal cost of the cleaned coal.
Oil from Coal and Garbage
Processes are being developed which wouldproduce low sulfur and relatively high heat value fueloil from coal. Coal is reacted with steam to producea low-cost gas with a high carbon monoxide content.Pulverized coal mixed with the oil product is reactedwith the gas and more steam at high temperaturesand pressures, producing oil, ash and hydrogen sulfidegas. This process has an important potential forhelping cope with municipal and agricultural garbage,since shredded garbage and other biological waste canbe substituted for the pulverized coal, producing a20 to 30 per cent yield of oil, based on the weightof the dried raw material.
Gas from Oil
One way in which natural gas supplies could berelatively rapidly expanded would be its productionfrom naphtha and other petroleum components. Thiscapacity could be developed much more quickly andwith less capital expenditures than coal gasification.In this process, the oil is first desulfurized by reactingit with hydrogen gas. It is then reacted with steamunder high temperature and pressure conditions toform a gas containing about 80 per cent methaneand 20 per cent carbon dioxide. The carbon dioxideis readily removed, leaving synthetic natural gas. Theproduct would cost significantly more than currentnatural gas, both because of the processing cost andthe cost of the oil feed. This approach may be usedto fill in the gap until coal gasification can beperfected.
Magnetohydrodynamics (MUD)
The one really advanced concept for improvingthe efficiency of generating electrical energy fromfossil fuels is magnetohydrodynamics. In thisconcept, hot flowing ionized gas is substituted forthe rotating copper coils of the conventionalelectrical generators.
Gases from the high temperature combustion offossil fuels are made electrically conductive by"seeding" with suitable chemicals. This electricallyconducting gas then travels at high speed through amagnetic field to produce a flow of direct current.The hot gases can then be used to fire a steam turbinegenerator, making the overall efficiency of thecomposite system as high as 60 per cer t, 1 1/2 timesthat of a modern fossil fuel plant. Laboratory-scaleMHD generators are in operation at the present.However, it is unlikely that large-scale electricalproduction from this source will become practicalbefore the end of this century. Although substantialproblems remain to be solved in materialsengineering, reliability, long-term durability andemission controls, MHD is one of the more promisingnew concepts of electrical energy currently understudy.
Enemy from the Sun
Diffused solar radiant energy (sunshine) can becollected and converted to ,:lectricity by severalmethods, including thermal conversion and directconversion. Sollr power plants have been proposedfor desert areas having a large number of clear days,tropical oceans and even outer space.
10
Thermal Conversion Systems
Thermal conversion systems would involvetrapping the sun's rays by an extens.ve array of steelpipes coated with materials which are heated byabsorbing the sunlight. Nitrogen flowing through thepipes would gather the heat and transport it to tanksof molten salt. The molten salt can be heated tc atemperature of about 1000 degrees F for productionof steam which would power conventional turbinesat a projected efficiency of about 30 per cent. Thearea required to supply energy to a 1000 megawattpower plant would be Aout 10 square miles ofcollection surface, plus a 30,00n gallon reservoir ofmolten salt. Some type of energy storage would benecessary for nights and cloudy days. Unfortunately,technology has not yet produced practical energystorage systems. Current batteries are impracticalbecause of their high cost and low efficiency.
Direct Conversion Systems
Direct conversion devices can convert solarradiant energy directly into electricity. One directconversion scheme is the launching of asatellite-mounted array of solar cells in synchronousorbit which would permanently locate the cells overa pre-selected position on the earth's surface. Radiantenergy would be converted into direct current whichin turn would be converted electronically intomicrowave energy. 'his energy would be beamed toearth to be collected by huge antennas located onthe earth's surface beneath the satellite. The energycould then be converted to alternating current. Atthe present stage of development, direct conversiondevices are prohibitively expensive and not veryefficient. The maximum efficiency of silicon cells sofar achieved is about 16 per cent. To meet New YorkCity's current power needs would require a solarcollector panel 25 square miles in size in space, witha receiving antenna 36 square miles in size on earth.Obviously, the initial cost of such a solar generatingstation would be much higher than that of presentstations. Operating expenses, however, would be verylow, since the "fuel"resource is free, and there wouldbe no moving mechanical parts in the system. Overa 40 year life, electricity costs might be lower thanthat from conventional sources.
Another use of direct conversion devices whenthey become more efficient and less expensive wouldbe to locate them on the roofs of buildings to supplya portion of the electrical needs of thebuildings,especially that required to drive airconditioning systems during hot summer days.
Solar Sea Power
Proposed initially by the French physiciJacques D'Arsonval in 1881, solar sea power h.recently received renewed interest. The conceptinvolves the use of temperature differeni.es betweensun-heated surfaces and colder water deep under thesurface to power heat engines. Vast areas of tropicalwaters offer a tremendous source of essentiallypollution-free energy. Since the water retains the heatof the sun, such plants, unlike other types of solarplants, could operate at night and during cloudyperiods.
The technology for such plants has yet to bedeveloped, but they are envisioned to be large,extending a half mile or more under the water toreach the deep cold water. Since the temperaturecifference between this cold water and the surfacewaters is only in the range of 35 degrees F, sucha power plant would have a thermal efficiency lessthan one-tenth of the efficiency of a conventionalmodern fossil fueled plant. This would necessitate thepumping of an enormous amount of water throughthe heat engine per killowatt hour of electricityproduced. The final problem with this approach isthat the tropical areas where such plants can be setup are far from most of the places where theelectricity is needed.
Power from Other Natural Forces
Geothermal Power
Power plants using hot water or steam that isstored in the earth from volcanic activity have beenin operation in Italy since the turn of the century.Sources of geothermal energy are currently underdevelopment in this country and New Zealand.
In a few locations, natural steam is available.In many places, hot water can be tapped as usableenergy sources. Also there are areas of intensely hotrock that can be used by fracturing the rock andforcing cold water down where it can be heated. Itcan be returned to the surface to produce steampower. Where available, this should be clean, cheapand almost pollution-free energy source. For all itsseeming simplicity, however, geothermal power is notwithout its problems. Corrosive hot water must behanuied and the turbines must be operated at lowefficiencies (10 to 15 per cent) because of therelatively low steam temperatures available. The saltwater from thne wells can become a source of water
11
pollution, and there is often the liberation ofhydrogen sulfide into the atmosphere. There alsoexists the possibility of land subsidence and anincrease in seismic activity.
Total exploitation of all of the cuuntry's knowngeothermal resources could supply less than one percent of the projected consumption of electricity bythe year 2000. So this energy source presents nosignificant solution to the long-range energyproblems.
Tidal Power
Tidal power utilizes the energy of tile flowingtides which reverse direction four times a day. Tidalpower plants can be located in only a few favorableplaces where a large tidal flow and head exist in abay or estuary which can be dammed. The basin isallowed to alternatively fill and empty, the waterbeing routed through reversible hydraulic turbines.Total exploitable tidal energy resources amount toless than one per cent of the projected United Stateselectrical consumption by the year 2000.
Wind Power
Propeller-driven generators can convert thewind's energy into electricity with an efficiency ofapproximately 70 per cent. Like water power, windpower has the advantage of producing no pollutionand no waste heat.
It is envisioned that such generators would belocated some 20 miles out in the omens or GreatLakes where they could catch the strong prevailingwinds. But because the wind is so highly variable,successful wind power generation, like solar power,is dependent upon energy storage, since the energymust be captured a: it becomes available in itscapricious moments. At best, wind power couldsupply only a small portion of our future energyneeds.
Fusion Power
The most probable long-range resolution to thedilemma of dwindling fuel is the process of fusion.which powers the stars. In fusion, two light nucleiare fused together to form a heavier nucleus, releasingnuclear energy. The fusion reaction will use the heavyisotopes of hydrogen called dueterium and tritium.Deuterium can be economically separated from seawater. and tritium can ba obtained in a nuclear
S.r.
ri
1!.
reaction involving lithium. The fusion process isexpected to result in smaller quantities of radioactivewaste than the current fission reactors. So here maybe the ultimate fuelcheap, abundant and availableto all.
To make controlled fusion work, one must heatan electrified gas called a plasma to temperatures onthe order of 300 million degrees C, hotter than theinterior of the sun. This gas must then be containedin some way so that it does not touch the walls ofthe vessel, and held in this condition for a fractionof a second until a fusion reaction takes place. Noone has yet made controlled fusion nroduce moreenergy than it consumes.
In the past. fusion research efforts have beendirected to the pal of igniting and cortaining fusionreactions within magnetic fields. Many scientists nowthink that a more feasible approach is the use ofhigh-powered lasers to initiate and ,:onfine suchreactions. This newer concept is to heat in pulsessmall pellets of deuterium and tritium with manyhigh-powered laser beams coming from differentdirections, instantaneously heating the pellets toignite fusion and at the same time containing therzilets in the converg!ag beams long enough to obtainuseful output of power.
Lasers big enoug;1 to test the feasibility of thisconcept are just becoming available. The technicalproblems that yet need to be overcome to be ableto build practicable prver systems based on eitherfusion concept are immense, probably putting thetime of the first fusion power plants into the nextcentury.
Small Unit Backup Electrical Power Sources
Internal Combustion Engine
One approach which is becoming increasinglyuseful in helping to solve short-term power shortageproblems is the use of internal combustion enginesin factory-assembled packages. These are currentlyavailable in 40 megawatt units which can be deliveredand set up far more quickly than any other type ofelectrical generating system. It is expected that 100megawatt units will he available by 1990. Thesesystems burn expensive high quality fossil fuels,resulting in less environmental pollution. They areprimarily used only when the electrical demandexceeds the capacity of the cheaper electricity from
12
turbine generators, or as emergency power sourcesclose to centers of large electrical demand.
Fuel Cells
Developed initially for on-board power for theGemini and Apollo spacecraft, fuel cells are attractingattention from utilities as small units or backuppower sources. In fuel cells, hydrogen, which can beproduced from just about any type of fossil fuel orthe decomposition of water, is 61emically reactedwith oxygen from the air to produce electricity. Thisis done electrochemically, without having to gothrough the inefficient combustion steps required bymost other fossil fueled electrical generatingnpproaches. This allows conversion efficiencies ashigh as 60 to 70 per cent.
Fuel cells emit almost 110 air pollutants, requireno cooling water and operate quietly. They wouldbe relatively small and inconspicuous.
Small units (12.5 kilowatts) using natural gas astheir energy source are now being installed insingle-family residences to supply the entire electricalneeds of the dwelling. larger (10 megawatt) unitshave been built and are being tested by variousutilities. Power plants with electrical generatingcapacities up to several hundred megawatts areenvisioned for the future. Such units would notsupplant other power generation sources, but wouldbe used as supplemental power systems which wouldgive electric utilities additional flexibility forproviding the right amount of power where and whenit is needed.
Increasing the Output of Electrical GeneratingPlants
The demand for electricity varies considerablyfrom season to season, day to day and eves! hourlythroughout the day, but electricity cannot begenerated and stored for the peak times. It must beconsumed as soon as it is generated. Thus thegenerating capacity of a system must be geared to:sleeting the peak load demand and there are largeperiods of time, especially during the night andweekends, when muth of this generating c ipacity isnot being utilized. Methods are being sought whichwould make greater use of this idle capacity.
Pumped Storage
Hydroelectric plants are useful to complementand supplement base load power. but as mentioned
previously, most sites in which hydroelectric plantscan be built have already been exploited. Thepumped storage concept utilizes the principle ofhydroelectric power generation and increases theutilization of existing power generation capacity.During periods of low electrical demand, theelectricity is used to pump water to high reservoirs.Then during periods of peak load electrical demand,the process is reversed and the stored water is releasedto turn hydraulic turbines to produce the additionalpower needed.
While such systems enable a higher utilizationof power plant equipment of the utility system, lossesin th, proc, ss amount to about 25 per cent. Thatis. for every four kilowatts us"cl to pump the waterto the reservoir, only three kilowatts are laterrecovered.
This type of facility is particularly well-suitedfor large communities with a concentration ofindustry and a hewer), but widely varying demand forpower. Suitable Mies for this type of fluxuating waterstorage re limited, and this concept is meetingincreasing opposition from environmentalists becauseit involws the flooding of large areas with the storedwater.
Hydrogen Fuel Economy
A proposed approach which is gaining increasingnumbers of advocates is the use of hydrogen gas asa fuel. Unlike fossil fuels, hydrogen would not bea primary source of energy, sine it is not found inany significant quantity in nature in its unreactedform. But it could be a carrier of enemy with vastflexibility.
Hydrogen is virtually an ideal fuel, since it burnsin air to form nonpolluting water vapor, with theonly possible pollutant being the nitrogen oxidesformed from the components of air. If it is burnedin pure oxygen, even this source of pollution iseliminated.
It would be easily transported in existing naturalgas piping systems and readily :hied near where itis needed for power generation. Actually. for the longdistance transmission of energy. it would be moreefficient to transmit hydrogen gas then to transmitelectricity over power lines, because of line losses.
It is envisioned that large coastal power plants,such as nucicar or solar sea power plants, would usetheir excess capacity for the electrolysis of water,producing oxygen and hydorgen gases. The efficiencyof these electrolyzers would be 60 to 70 per cent.The large plants could therefore be operated
13
continually at 100 poi cent of their installed capacity,and the hydrogen (arid if needed, the oxygen) wouldthen be pied to terminals and dispersed throughoutthe local areas to be stored until needed. They wouldthen be burned in efficient combustion turbines orin even more effHent fuel cells.
The major obstacle for the largm ale future useof hydrogen depends on a large exte.:., on society'sovercoming what has been called the "Hindenburgsyndrome" Most of the older members of ourpopulation can still picture in their minds thenewsreel film of the hydrogen-filled German zeppelinHindenburg which crashed in flames and killed severalpassengers. However, proponents of the use ofhydrogen fuel fee! that if it is properly handled, itwill be as safe as natural gas is today.
Chapter 3
NUCLEAR
THE FISSION PROCESS
POWER PLANTS
When atoms of certain heavy elements arcbombarded by neutrons, the nuclei of some of theseatoms will capture a neutron and become unstable.Such an atom will then change in one of several ways.One possibility is for the unstable atoms to fission,or split into two or more smaller atoms. Togetherthe fission products weigh slightly less than thecombined weight of the original atom and thebombardinp, neutron, and this missing weight ormass has been converted into energy, as describedby Einstein's formula: energy equals mass times thevelocity of light squared (Earmc2). As the fissionfragments fly apart, most of this energy appearsalmost instantaneously as heat as the fragments losetheir energy of motion to the surrounding material.The heat from this fission reaction can then be usedto boil water to make steam. This steam can be usedto spin turbines and generate electricity. Thus theonly difference between nuclear and fossil fuel poweris the s )urce of the teat energy.
When an atom fissions, several free neutrons arereleased. These are available to strike other atoms,causing them to fission. This is the chain reaction(Figure 6). If the chain reaction is to continue, theremust be enough atoms packed close enough togetherto insure the capture of enough neutrons to keepa constant rate of fission. The amount of materialrequired for this is called the critical mass.
Generally, the smaller atoms produced in thefission process, called the fission fragments, areunstable. To change to a stable state, they throw offcharged subatomic particles and/or electromagneticwaves. This process is called radioactive decay.Substances which change in this fashion are calledradioactive: the products are radiation.
During radioactive decay, three principal typesof radiation can be emitted from an atom. Heavynuclei such as the naturally-occurring isotopes ofuranium and thorium often decay by the emissionof alpha particles, which are high energy heliumnuclei. Other atoms decay by the emission of betaparticles, which can be either high energy negativelycharged electrons (negations) or positively chargedelectrons (positrons). These also originate from thenucleus of WI' decaying atom. Fission fragmentsusually decay by the emission of negatively chargedelectrons. Decay by the emission of these particlesis usually followed by the emission ofelectromagnetic radiation of two types: gamma rays,
14
which are produced in the nucleus of the decayingatom, and x-rays, which are produced as a result ofthe rearrangement of orbital electrons. Except fortheir origin and the fact that x-rays are usually oflower energy and therefore are less penetrating, x-raysand gamma rays are the same.
Loss of this radiation changes the atomicstructure of the radioactive substance, a processwhich continues until a stable (nonradioactive)element is reached. Uranium, for instance, isradioactive, and decays slowly into elements likeradium, radon and polonium and finally stops at lead.1 he time required for one-half of the radioactiveatoms of an element to decay to its daughter speciesof atoms is known as the half life of that element.If an atom has a short half life, it will quickly decayaway. Half lives vary from minute fractions of asecond to millions of years.
Figure 7 shows one of more than 30 possiblechains of decay following the fissioning of an atomof uranium-235. The fission fragments are atoms ofradioactive bromine and xenon, and they each decaythrough many steps by emitting beta particles. Thehalf life for each part of the chain is shown. Notethe diversity of the half life lengths.
NUCLEAR FUEL
Uranium is the basic nuclear fuel because itcontains uranium-235, the only substance found innature that readily undergoes fission. The naturalconcentration of uranium-235 in uranium isseven-tenths of one per cent, the balance beinguranium-238, which does not readily undergo fission.
The United States has become the leadingproducer of uranium in the free world. Practicallyall the deposits of commercial-grade uranium orefound in the United States to date are in the westernpart of the country. Some of the deposits are shallowand mined by open-pit techniques, but the greaterpart comes from underground mines.
Uranium mining disturbs land areas, but muchsmaller areas are involved than in the mining of coal.Around 30,000 tons of uranium ore must be minedand milled to produce the 30 tons of uranium neededto fuel a nuclear reactor for a year. On the otherhand, about 12 million tons of overburden must beremoved in a strip mine to ship the two million tonsof coal per year needed for a comparable coal-burningplant.
FISSION FRAGMENT
NUCLEAR FISSION CHAIN REACTION
STRAY NEUTRON
U233
BEST
ORIGINAL FISSION
FISSION FRAGMENT
ONII TO TIMES NRUTRONS PROM FISSION PROCSSIN
CHANGE TO PLUTONIUMONE NEW FISSION
A NEUTRON SOMETIMES LOST
FISSION FRAGMENT
TWO NEW FISSIONSDNS TO TURIN NIUTRONS PROM FISSION PR 00111115
FISSION
FRAGMENTFISSION FRAGMENTS
FIGURE 6
15
FISSIONFRAGMENT
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NU( LEAR REACTORS
A nuclear reactor serves to provide anenvironment in which fission reactions can heinitiated, sustained and controlled, and to makepossible the removal of heat for power production.
Certain components are common to all reactors,regardless of their design. These are the core, coolant.control rods and shielding. Most current types ofpower reactors also include a moderator.
The core itself is generally made up of bundlesof fuel rods which contain uranium oxide pellets.When a number of bundles of rods are assembled,a critical mass is reached and the chain reaction starts.Individual fuel rod.; do not contain sufficient fuel fora critical mass.
The coolant, either liquid or gas, flows over thefuel rods, removing heat from the fuel. The coolantdoes not come in contact with the actual fuel, sincethe radioactive material itself is sealed within the fuelrods.
The control rods are made of materials thatreadily absorb neutrons. These rods are usually stripsof metal (boron or cadmium), positioned inside thefuel assembly. If the rods are pulled out of thebundle, more neutrons are available to causefissioning of the fuel, so the rate of reaction increases.If the rods are inserted into the fuel bundle, theyact as a neutron sponge so that there are fewerneutrons available to the fuel. Thus the chain reactionslows or may be stopped completely. This makes itpossible to produce heat at a desired rate or to shutdown the reactor completely.
The moderator is a material in the core whichserves to slow down the neutrons as they emergefrom the fissioning atoms. This is necessary becauseneutrons travelling too fast are less readily capturedand do not cause more fissions. Graphite, water orheavy urPr are commonly used moderators.
The shielding consists of components made ofspecial materials which surround different portionsof the reactor system to prevent radiation fromescaping into th. environment. Some shieldingcomponents reflect stray neutrons hack into thereactor. Others soak up radiation to protectimportant structural members from radiation damage.Still other shielding components prevent radiationfrom escaping and causing biological damage.
17
In many designs, one of the reactor parts mayserve to complement the others. For example, themoderator may act as a neutron reflector. Thecoolant in some reactors also serves as a moderator.Many combinations like these have been developed,each of which has certain advantages anddisadvantages.
Major reactor components arc shown in Figures8, 9 and 10. The reactor core which is shown withinthe reactor vessel of Figure 8 is approximately a rightcylinder with a diameter of about 11 feet and aheight of 13 feet. The core is made up of 177 fuelassemblies which weigh about 1500 pounds each. Thefuel assembly is in turn a vertical stack of 180 fuelrods and 16 guide tubes for the neutron-absorbingcontrol rods (Figure 9). Each fuel rod is a zirconiumalloy tube about 0.4 inches in diameter with a wallthickness of about 0.025 inches (Figure 10). Withinthe zirconium tube, called cladding, is a vertical stackof uranium dioxide fuel pellets containing slightlyenriched uranium. Enriched uranium contains moreof the fissionable uranium-235 than thenaturally-occuring percenta.,e. These pellets are aboutthree-eights of an inch in diameter and three-fourthsof an inch long. Each fuel rod is held in a lowerspacer grid, several intermediate spacer grids and anupper grid and housing.
TYPES OF REACTORS
The more common types of reactors are thelight water reactors, including the boiling waterreactor and the pressurized water reactor: and thegas cooled reactor. Of all the power reactors orderedfor construction in this country as of September1971, 35 per cent were boiling water reactors, 62per cent were pressurized water reactors, one per centwas gas cooled and two per cent were other types.A 111.ii0F research program is underway to developanother type, the fast breeder reactor.
Boiling Water Reactors (BWR)
In the boiling water reactor (Figure 11), wateris used as the coolant and serves a secondary functionas the moderator and neutron reflector. The wateris brought into the reactor and allowed to boil. Itthen is taken out of the reactor as pressurized steam.The steam is used to drive a turbine, producingelectrical power. Typically. a BWR operates at a
pressure of about 1000 pounds per square inch andproduces steam at about 550 degrees Parenheit. TheBWR has the advantage of simplicity. but suffers
FIGURE 8SCHEMATIC ARRANGEMENT OF BOILING WATER REACTOR
Control Rod Aaaistblif
FUEL ASSEMBLY
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FIGURE 9
19
ANNULUS
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INSULATOR - WAFER
FUEL CLADDING
FIGURE 10
CUTAWAY OF FUEL ELEMENTFOR NUCLEAR REACTOR CONE
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from the disadvantage of .requiring a large core forcooling purposes. Some of the atoms and materialsdissolved in the water may become radioactive andhe carried through to the turbine section, increasingthe area where radiation exists. The early models ofboiling water reactors suffered from a high emissionof radioactive gases as compared with other reactors,but this has been significantly reduced in newermodels. Boiling water reactors still emit moreradioactive gases such as xenon, Krypton, and iodinethan contemporary pressurized water reactors.
Pressurized Water Reactors (PWR)
In a pressurized water reactor (Figure 12),pressure keeps the water from boiling. Instead, it ispumped through the core and is removed at the topas a heated liquid. The water is then circulatedthrough a heat exchanger in which steam is producedfrom water in a secondary loop and used to drivea turbine. The cooled water in the primary loop isthen returned to the reactor to again cool the core.The PWR normally operates at pressures of 2000pounds per square inch and about 660 degreesFarenheit. The PWR has several advantages over theboiling water reactors. The coolant used at thereactor core does not directly contact the turbine.Thus the turbine area remains uncontaminated withradioactive materials The higher pressure allows moreefficient heat transfer and requires a smaller surfacearea for the core. The PWR, however, requires higheroperating pressures and additional heat exchangers,which lowers its efficiency The high temperatureincreases the corrosion of the fuel rods, the cladding,and the vessel.
Iligh Temperature Gas Cooled Reactors(IITGR)
In the high temperature gas cooled reactor(Figure 13), as the name suggests. the core is cooledby passing certain gases over it. Usually purifiedcarbon dioxide or helium is the gas employed as thecoolant. This type of reactor has a low fuelconsumption rate. because very few neutrons arecaptured by the coolant, but it has several drawbacks.Since gases are not as efficient heat transfer agentsas liquids. a large volume of gas must he circulated.The circulation system requires very large blowersand the core must also he large in order to presentcnimgh surface area foi effective cooling. Gases alsoare Font moderating materials, so a separatemoderator system must he installed. This moderatorsyst..in usually consists of graphite blocks pierced tocontain the fuel Graphite is used because it is very
strong when hot, permitting the reactor to operateat a high temperature. Neither helium nor carbondioxide wilt react with the graphite. The gas coolantgives up its heat to water circulating through a steamgenerator. Since the gas coolant can be heated tomuch higher temperatures than can water coolant,it can produce steam at much higher temperaturesthan the water cooled reactors.
This high temperature operation allows the useof the best turbine tecnnology and reduces Inc releaseof waste heat. These factors may give this type ofsystem an efficiency equal to that of the best fossilplants. Current water cooled plants have somewhatlower efficiency than modern fossil fueled plants, andtherefore are potentially sources of greater thermalpollution.
Breeder Reactors
It has been noted that uranium is the basic fuelfor nuclear reactors because it contains fissionableuranium-235. It was also seen in Table 5, that thehigh grade ores of this material are estimated to hedepleted by the the year 2040. Breeder reactors are
looked upon as a method of extending this limitedfuel supply so that it will last hundreds of yearsbeyond the estimated date, because breeder reactorsproduce more fissionable material than they
consume.
Although uranium-238 is not readily fissionable,it converts, under neutron irradiation, intoplutonium-239, which is fissionable. For this reason,uranium-238, which constitutes more than 99 percent of all uranium, is called a fertile material. Theelement thorium, which is abundant in nature, iscomposed of thorium-232. This is also a fertilematerial, converting under neutron irradiation tofissionable uranium-233. The uranium-233 and
plutonium-239 can be recovered for use in otherreactors.
This conversion from fertile to fissionable
material also takes place in current types of powerreactors, but not at such a high late as in breeders.When an atom of uranium-235 fissions. it produceson the average about 2.5 neutrons. To maintain achain reaction, one of these neutrons on the averagemust be captured by another atom of uranium-2;5to produce the next generation of fission events. Thisleaves about 1.5 neutrons per fission which c:Iti hecaptured in the core, or he captured by the urnuuttt-238 in the fuel to produce plutonium. In curient
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water and gas cooled reactors, it takes the fission oftwo atoms of fuel to convert one atom ofuranium-238 to an atom of plutonium-239.
In a breeder reactor, for each atom of fissionablematerial consumed, more than one atom of fertilematerial becomes fissionable material. This isachieved by increasing the number of free neutronsreleased in fission and by decreasing the number ofneutrons wasted, thereby making a larger numberavailable for absorption in fertile material.
Fuel produced in breeder reactors may greatlyextend our energy resources, since breeder reactorscould utilize more than 50 per cent of the availableenergy in the world's fissionable and fertile fuelreserves as compared to only one or two per centfor light water reactors. One other favorable aspectof breeder reactors is that their fuel can be producedeconomically from lower grade ores. We will needto turn to these ores as supplies of high-grade oresare consumed.
In 1970, President Richard Nixon said in amessage to Congress, "Our best hope today formeeting the nation's demand for economical cleanenergy lies with the fast breeder reactor. Because ofits highly efficient use of nuclear fuel, the breederreactor could extend the life of our natural uraniumsupply from decades to centuries, with far less impacton the environment than the power plants which areoperating today."
President Nixon established as a national goalthe successful demonstration of a breeder technologyby 1980. By 1972 the federal government had spentsome $650 million to develop the liquid metal fastbreeder reactor. More will undoubtedly have to bespent before commercial breeders are available. Onthe other hand, several groups. including theScientist's Institute for Public Information andFriends of the Earth, have seriously questioned thegovernment's commitment to breeder technology onthe grounds of public safety. and recommend thatthe government spend more money on thedevelopment of alternative sources of electricalenergy.
Just as there were initially many thermal reactorconcepts, with the PWR. BWR and gas cooledreactors winning general acceptanc: in this country,there have been a number of breeder reactor conceptsproposed. The concepts which have undergone initial
25
development include the light water breeder reactor(LWBR) and the molten salt breeder reactor (MSBR),which are eased primarily on thethorium-232-uranium-233 feel system: and the gascooled fast breeder reactor (GCFBR) and the liquidmetal cooled fast breeder reactor (LMFBR), basedprimarily on the uranium-233-plutonium-239 fuelsystem. Of these, the LMFBR concept is receivingthe major focus of the research and developmentefforts in this country and abroad. Thus only thisconcept will be treated further
Liquid Metal Cooled Fast Breeder Reactors
The LMFBR would be able to produce morefuel (plutonium-239) from the fertile uranium-238than it would consume. A diagram oi the liquid metalfast breeder reactor appears in Figure 14.
It is called a fast reactor because it contains nomoderator material to cause a rapid slowdown of thefission neutrons. Thus the average neutron velocityin the core will be considerably greater than inconventional reactor cores. At these higher energies.there is a much greater probability that the neutronsnot needed to maintain the chain reaction will becaptured by the fertile uranium-238 than by reactorcore components.
The term liquid metal is used because liquidsodium is the reactor coolant. An inert cover gas(argon) is used to blanket the sodium.
The fuel in such a system would probably hea mixture of oxides of uranium and plutonium.
Liquid metal fast breeder reactors have thepotential of greater efficiency than light waterreactors. Sodium is considerably more efficient thanwater in transferring heat from the care. Also, thereactor core can he operated at a higher temperaturewithout pressurization, since sodium ha.; a muchhigher boiling point than water. As a consequence.the thermal efficiency of such a power plant will he39 per cent or more, compared to 31 to 33 per centefficiency for light water reactors. This means adecrease in waste heat.
The LMFBR has some disadvantages whencompared with light water reactors. Tliese
,,advantages are due mainly to the sodium coolant.Sodium is a highly chemically reactive metal whichwill burn if exposed to either water on Finther.
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it is a solid at room temperature and requires aelaborate heating system to assure that it will remainliquid at all times throughout the coolant system.Sodium is not transparent to light, which complicatesrefueling and maintenance.
The sodium coolant will captu re some of thereactor neutrons and become intensely radioactive.Since the main radioisotope produced (sodium-24)has a 15 hour half life and emits extremelypenetrating gamma rays, refueling of the reactor andmaintenance of the primary coolant system willrequire remote control equipment.
The LMFBR is more difficult to control thana light water reactor because an accidental loss ofthe sodium coolant from the core results in anincrease in reactor power. The opposite effect occursin light water reactors.
The cost of building a LMFBR will beconsiderably greater than that of light water reactors,primarily because of the more exacting specificationsand closer tolerances required.
These problems are now being solved in smalloperating prototype systems. It is the United State'sgoal to develop two or more prototypes in the 1970sand to have larger plants operational in the 1980s.Some other nations appear to be more advanced inthe development of breeder reactors than the UnitedStates.
SAFETY SYSTEMS IN NUCLEAR REACTORS
No accident affecting the public health andsafety has occurred in a commercial nuclear powerplant. Furthermore, no radiation injury to a plantworker has occurred in such a plant. This record isdue to stringent safety precautions taken by thebuilders of nuclear plants. A nuclear power plantcannot be built or operated without a license fromthe U.S. Atomic Energy Commission. which is
charged by law with the responsibility of satisfyingitself that the plant will not endanger public healthand safety.
Control During Normal Operation,
Nuclear power plants form small quantities (onthe order of serveral pounds per day) of radioactivesubstances. In normal operation, more than 99.99 percent of these substances remain %Off in the fuelassemblies. The small amount that gets out of the
27
fuel enters the reactor coolant system and is removedby purification equipment. An infinitesimally smallamount of radiation is released to the environmenton a strictly controlled basis, subject to conservativeand rigidly enforced Atomic Energy Commission(AEC) health and safety regulations. This is discussedin greater detail in Chapter 5.
Accident Prevention
Natural Safeguards
Today's water moderated power reactors useuranium dicxide fuel which is enriched with theuranium-235 isotope to only three or four times itsnatural level. If the rate of fissions were to increasesignificantly, more heat would be produced. The heatwould increase the energy of the neutrons in the fuel,and thus increase the proportion of neutrons escapingfrom the core and captured by nonfissioning atoms.The rate of fission would thus slow down. This effectis automatic and instantaneous, and is one reasonwhy a nuclear reactor cannot possibly become abomb. In a bomb, essentially pure fissionable materialis required, and it must be rapidly compressed andheld together for the chain reaction to increase toan intensity of a nuclear explosion.
The use of water as a coolant and moderatorprovides another safety feature of today's powerreactors. If the reactor were to exceed its designedpower level, it would raise the temperature of thewater, which would in turn decrease the water'sability to act as a moderator. This tends to reducethe reactor's power level.
Engineered Safeguards
In addition to the natural safeguards. manysafety features are built as an integral part of anyreactor facility. These include the following.
1. Monitoring of reactor neutron intensity.
Since neutrons initiate the fission reactions andrelate to the reactor power level, measurementsof the number of availchle neutrons arc madeby a number of independent monitoring systemsat various locations in the reactor core. Theseinstruments are connected to a rapid shutdownsystem in case the neutron intensity rises abovea preselected
2. Reactor control systems
Materials such as boron or cadmium have theability to absorb neutrons, and so may be usedto shut down a reactor by removing neutronsfrom the system. thus preventing new fissionsfrom occurring. Common methods ofintroduction include the mechanical insertion ofcontrol rods into the core, or the addition ofliquid solutions of these neutron -absorbingelements to the water moderator. Most waterreactors have both methods of control available.
3. Reactor safety circuit instrumentation
Instruments constantly monitor what is
happening in the core. Improper signalsconcerning temperature, pressure, or othermeasurements will cause immediate reactorshutdown. Each safety system has one or morebackup systems which operate when there is afailure in the primary system.
4. Electric power rcquirements
Reactor designers assume that at some time allelectric power available to a nuclear plant mayhe shut off. To allow for this possibility, reactorsystems are usually designed so that they requireno electric power to achieve safe reactorshutdown. Those which may require power aftershutdown, for example, to keep the coolantcirculating, are equipped with emergency dieselgenerators and batteries to supply electricity forthe reactor when no outside power is available.These are test tun at intervals to insurereliability if and when they are needed.
5. Emergency core cooling network
If for some reason there is a rapid loss of coolantwater in a nuclear reactor, it is conceivable thatthe core might melt due to heat from the fissionreactions. releasing a dangerous amount ofradioactive material Two independentemergency core cooling systems are madeavailable to provide emergency core cooling. Thenetwork fully automatic, and does not requireoperator intervention during the initiation of theemergency core cooling systems. Theeffectiveness of some of the current emergencycore cooling systems has been seriouslyquestioned, so they arc now under very closestudy
28
Containment in the Event of Accidents
As has been seen, there are multiple physicalbarriers in reactor systems to guard against the escapeof radioactive substances into the environment. Thismultiple barrier concept recognizes that theradioactive fission products must be contained withinthe reactor system in order to avoid exposing thepublic to radiation. There is first of all the abilityof the fuel material to retain most of the fissionproducts, even when overheated. Then there is thefuel element cladding through which fission productsmust pass in order to get into the reactor coolant.Next there :i.e. the walls of the reactor vessel itself.Finally there is the containment system, constructedto halt any release of radioactive material that getspast all the other barriers. The reactor building itselfforms a secondary containment system, and may besealed off as a further safety move. Figure 8 showssome features of a containment system.
NUCLEAR POWER PROBLEMS
The development of nuclear power stations hassuffered from sharply escalating construction costsand numerous construction delays.
Original schedules for many proposed nuclearplants have not been met because of difficulty inobtaining the necessary licensing. Hearings for variouslicenses by the AEC, state agencies and other groups,once nearly routine, have become battlegrounds forenvironmentalists concerned about radiologicalsafety, plant siting and thermal pollution.
Even though the electrical power industryregards nuclear power plants as the answer for thelong term, it is less than happy with nuclear plantperformance to date. Many plants arc operating atlow: than expected efficiencies. and have hadproblems which have caused them to he shut downfor long periods.
Chapter 4
}.()SSIL FUELED ELECTRICAL GENERATING STATIONS
THE COMBUSTION PROCESS
Many millions of years ago. the earth laid downthick deposits of organic materials. Under heat andpressure these materials became coal, oil and gas.When these fossil fuels are burned, they release heatenergy which can be used to produce electricity.Coal, oil and gas are composed mainly of hydrogenand carbon. In the combustion process, they producecarbon dioxide and water vapor, plus byproductssuch as sulfur dioxide, oxides of nitrogen, unburnedhydrocarbons. carbon monoxide and ash.
FOSSIL FUELED PLANTS
Most large fossil fuel-burning plants are similarin design. (Figure 1 5) Fuel in the form of crushedcoal. oil or gas is blown under high pressure into largeboilers. Flames and hot gases resulting from theburning of the fuel pass over and around thousandsof tubes filled with water. The water inside the tubesis converted to steam which collects in steam drumsat the top of the boiler. The steam is then used toburn turbine generators to produce electricity.
The most noteworthy developments in fossilfuel generation in recent years has been the increasein plant size from about 700 megawatts to 1300megawatts. These units have increased their efficiencyby going to higher steam pressures and temperatures.Such plants are going to higher stacks for pollutiondispersal, electrostatic precipitators for particulatecontrol, and increased use of low sulfur fuel.
Gas
Gas is considered as the cleanest of the fossilfuels. since it is essentially methane which can bereadily burned completely :o carbon dioxide andwater. it usually has a very low sulfur content. Theburning of natural gas creates little noise, water orair pollution, with the main pollution being theoxides of nitrogen formed in the combustionchamber from the nitrogen and oxygen in air.Transmission of gas is normally through pipelinesunder the ground. They are reasonably safe and have
29
little environmental impact, with the possibleexception of the Alaskan pipeline. which will haveto be carefully designed to prevent damage to thefragile Arctic environment.
Unfortunately, natural gas is being used upfaster than new reserves are being discovered. Electricutilities will probably be among the first to sufferfrom the gas production deficiency. It is anticipatedthat by 1990 there will he none available for useas fuel for electric utilities. More and more thenatural gas will have to be supplied from oil and coalgasification and from shipment from places as faraway as Siberia.
Petroleum companies are starting to make!ong-term commitments to foreign countries for thepurchase of liquified natrual gas. To be economical.this will have to be shipped in large super-sizedtankers whose use will require the construction oflarge ports along our coasts. The proposedconstruction of such ports is now being attacked byenvironmentalists because of the environmentalimplications of their building and operation.
Oil
Because of the lack of economical technologyfor removing sulfur from coal, utilities and industriesare turning to oil to meet the 1970 Clean Air Actrequirements. especially in the northeastern lqiitedStates. The slowdown in building nuclear powerplants has added to this burden on the oil resources.
Wells in the United States (except Alaska) arecurrently pumping oil at capacity, and still thedemand for oil cannot he met. We already importone-fourth of our oil, and the National PetroleumCouncil estimates that by the early 1980s we mayneed to bring in half of our oil supply from abroad.
Those responsible for our national securityworry about becoming dependent on foreign oilsources, especially those in the oil-rich but politicallyvolatile Middle Fast. What would happen if Ilk Arabstates should cut off our oil shipments?
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Economists are worried about the huge increasein the balance of trade deficit if we turn to foreignsupplies of oil. For example, Saudi Arabia has morecrude oil reserves than the United States and LatinAmerica combined. It is estimated that by 1980Saudi Arabia will have the money to purchase onearajor United States corporation per year from dollarsobtained from fuel sales.
In addition to the oil supply problem there isa problem of refinery capacity. Most United Statesrefineries are running at maximum capacity, and nonew refineries are slated for completion before 1974.There are no longer sufficient overseas refiningcapabilities, dock and terminal facilities or tankersto meet increased needs. Super-sized tankers andports are needed for receiving increased oil shipments.
Competition exists for the amounts of availableoil. For example, an increase in the number of cars,plus engine modifications to reduce emissions andincreasing use of air conditioning and poweraccessories, has increased gasoline consumption andtherefore reduced capacity for fuel oil production.Oil and gas are rapidly becoming too valuable to burndirectly. We must begin to think in terms ofconserving them as raw materials for makingchemicals and foodstuffs which will be needed hi themore distant future.
Onshore oil production rarely presents anysignificant pollution problems. although accidentalpollution may sometimes occur from blowouts ofwells or losses of oil in storage or transportation.Offshore operations present more problems, with oilspills and fires at the wells. Oil spills and dischargesfrom tankers are also important problems to besolved. There is also the problem of contaminationof inland waterways and harbors resulting fromtransfer of oil between or from vessels.
Coal
The fossil fuel use situation is the reverse of thefuel supply. Oil and gas supply three-quarters of U.S.energy needs including transportation, whereas coal,which supplies 20 per cent of the U.S. energy,represents three-quarters of the fossil fuel reserves.Coal is found in 38 states, and there are some 1.5trillion tons of known reserves (Figure 16). TheUnited States has more knowi, coal reserves than therest of the free world combined.
On the face of it, this substantial reserve should
31
last for hundreds of years. But coal offers specialproblems. It is the worst offender of producing sulfurcompounds which are harmful pollutants. Thisproblem is discussed in Chapter 5. Its geographicaldistribution is not the best. Figure 16 shows thatmost of the eastern coal is anthracite, which has ahigh sulfut content, while most of the low sulfurlignite coal is located in the west, far from placeswhere the energy is most needed. Coal is alsoresponsible for large amounts of waste products.These are discussed in Chapter 6.
Furthermore, getting coal out of the groundwithout major damage to the environment hasbecome a serious problem. Underground coal minespollute the water table, harbor fires, and have causedmillions of acres of surface land to subside, breakingroads and sewers and collapsing buildings.Underground mining is a hazardous industry in termsof mine accidents and disabling black lung disease.
Strip mining is safer, and much cheaperit costsonly about half as much to mine by snipping, thanby deep mine operations. Currently 44 per cent ofall coal mined comes from strip mining. But stripmining destroys surface landscapes and can polluteriver and water supplies with silt and acid minedrainage. It is possible, however, to prevent much ofthis damage through proper land reclamation.adequate drainage and planting to achieve soilstabilization. Supporters of tough anti-strippinglegislation estimate that meaningful reclamation ofstrip mines would add about 15 cents per month tothe average consumer's electric bill. Sonic states nowhave partial bans on strip mining, and others havesome type of reclamation requirements. but of themore than 1.5 million acres of American landstripped for coal. two-thirds are unreclaimed, andthese areas keep on producing acid drainage, erosionand esthetic blight.
Delivery of coal is often hampered by a slit)) Cageof railroad hopper cars and the problems of minesbeing closed by strikes.
Since transportation of coal is so expensive,some companies are building power plants atop thecoal mine and sending the electricity to market bywire. For e xa mple. moyiPhila delphia-Bakimilie-Washington consumeis getelectricity from a trio of huge mine-mouth 'limosatop Chestnut Ridge. an immense en:it-bear inr.mountain in western Pennsylvania.
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Coal Gasification
Coal gasification offers the best long-termsolution to the problems of gas supplies and shouldproduce a clean method of utilizing our coal reserves.Domestic gasification would not be subject to foreigncontrols of fuel, and would not adversely affect theU.S. balance of payments. It would also provide newjobs for the depressed job market in rural coal miningareas of the country.
Coal gasification has top priority among all theDepartment of interior programs related to coalconversion. President Nixon has singled out coalgasification along with nuclear breeder reactors forspecial attention and stepped-up federal funding.Representative Mike McCormack, Chairman of theHouse Task Force on Energy, has stated, "Coalgasification is just as important as the breederreactor."
In coal gasification, water is heated to steamalong with oxygen and reacts with coal to makehydrogen-rich gas containing carbon monoxide,methane, hydrogen sulfide, and ammonia. The gas iscleaned of its unwanted constituents, leaving onlycarbon monoxide, hydrogen and methane. What isleft is combustible, but has a low heat contentcompared to natural gas. The final step, and the oneyet to be proven on a commercial scale, is to upgradethe heat content and cleanliness of this product. Ina process called methanization, there is a furtherreaction of the carbon monoxide and hydrogen toproduce more methane. The final product is thenabout equivalent in heat content to natural gas.
It is expected that about two per cent of thenatural gas will be made in this manner by 1985,and about 10 per cent by the year 2000. The gasproduced will probably be expensiveabout doublecurrent gas pricesbut competitive with othersupplemental sources such as liquified natural gasfrom the Middle East or Russia.
The process needs large amounts of water tomake the steam. Water consumption in the west.where most of the potential coal gasification sites arelocated, has long been a problem. Future gasificationsites will probably be limited by water requirementsrather than by coal reserves.
Initially the price of such gas would be too highfor use by electric utilities, but it could be used forcommercial applications. Coal gasification is expected
33
to doub!e present coal consumption by 1985. Stripmining is expected to be used to a large extent,requiring a large amount of restoration of minedareas.
Thermal pollution by coal gasification plants isexpected to be significant, since the conversion topipeline gas is expected to be only about 65 per centefficient. Disposal of large amounts of coal ash is alsorequired. Fortunately, coal gasification is carried outin a closed vessel, which should prevent anysignificant air pollution.
Although the preceeding coal gasificationprocess will not be immediately useful for powergeneration, a composite process looks very promising.In this process, the gas produced from the reactionof coal, air and st^am has the sulfur and ash removedand is burned directly in a gas turbine. Gas turbineshave the potential of better efficiency than steamturbines because they can operate at much highertemperatures. The hot exhaust gases from the turbineare run through a recovery boiler to produce steamwhich is led to a steam turbine to make moreelectricity. The result is a plant which should bemuch cleaner and more efficient than conventionalcoal burning plants.
In summary, despite the various technicalproblems which must be solved in its use. theextensive wealth that this country has in its coalreserves must be utilized in supplying much of ourenergy needs for the foreseeable future.
Chapter 5
BIOLOGICAL EFFECTS:
In this section we will consider the biologicaleffects of radiation, as well as the effects of exposureto the more traditional fossil fuel-generatedpollutants: sulfur dioxide, particulates, nitrogenoxides gnd hydrocarbons. We will also discuss thebenefit-risk concept. The greater part of this chapterwill describe the effects of exposure to radiation. Thereason for this is two-fold: much more research hasbeen done on the effects of radiation than on theeffects of the other pollutants; and radiation effectsare not well understood and are feared by the averageperson.
In the case of both radiation and traditional airpollutants, most of the reliable data on effects onhumans was gained from statistical analysis of casesin which people received large doses. Much less isknown about the effect of exposure to very smallamounts of these pollutants.
It is only within the last 20 years that one hasbegun to suspect problems because of air pollutantsfrom use of fossil fuels, and has begun to try tocontrol these problems. This is after thousands ofyears of burning fuels for the release of energy.
The case of exposure to radiation is similar onlyin part. Humans have been living with low levels ofbackground radiation since the beginning of time onearth. fhey were unaware of its existence until about1895, when radioactivity was discovered. The earlyexperiments with x-rays soon produced a number ofinjuries to the experimenters. Almost immediatelythe use of this phenomenon began to be controlled.
Table 6
A COMPARISON
By the time power reactors began to be built in themid-1950s. the radiation emitted from these plantsand the radioactive byproducts produced were understrict regulation. This is in contrast to the case forfossil fuels, where regulation followed long after theirdevelopment as energy sources.
BIOLOGICAL EFFECTS OF NUCLEAR POWERPLANTS
Fundamental Information
All matter is made up of simple units calledatoms. These atoms each have a nucleus which hasan electrically positive (+) charge. A cloud ofelectrically negative (-) electrons orbit around thepositive nucleus. Ordinarily the number of negativeelectrons equals the number of positive charges onthe nucleus. The atom is then electrically neutral. Ifenergy is supplied to an orbital electron, it can bemoved to a position further from the nucleus, andthe atom is said to be in an excited state. If largeamounts of energy are supplied, the electron canescape from the atom completely.
When one or more electrons is separated fromthe atom, the atom is said to be ionized. The atomhas a net positive charge since it is missing anelectron. This positive atom taken with its separatednegative electron is called an Ion pair. (See Figure17).
It was seen in Chapter 3 that some atoms areradioactive, and these atoms emit radiation as theydecay to a stable state. Table 6 shows thecomposition of the various kinds of decay radiation.
When these radiations pass through matter, theyinteract with the electron clouds of the atoms in thematter. In this process the radiations lose their energy'by exciting the atoms and/or producing ion pairs inthe matter. This basic process is essentially the samefor all kinds of materials-air, water, people, cementblocks and steel.
The most penetrating of these radiations aregamma rays. High energy gamma rays can completelypenetrate a person or a concrete block or a sheetof lead.
Beta radiations, which are high energy electronsor positrons, are capable of penetrating a piece ofaluminum foil or several layers of a person's skin.In air their range may be as much as a yard.
Alpha radiations, which are high energy heliumnuclei, can sometimes penetrate a very thin piece ofpaper, but cannot penetrate conventional aluminumfoil. Alpha radiations are not important in terms ofexternal radiation. They are, however, the mosthazardous of all types if they are located within thebody as a result of swallowing or inhaling an alphaemitter.
The injury-producing potential of any kind ofradiation depends on the rate of energy loss as theradiation travels through matter. This rate of energyloss in turn depends on the electrical charga andenergy of the radiation. This energy loss pr9duceschemically reactive species such as ion pairs in theabsorbing material, and these species do the damageby disrupting the functions of the cells.
Radiation Detection
The presence of atomic radiation is notdetectable by the human senses except in massivedoses, but it is easily detected by several types ofinstruments. One of the simplest radiation detectorsis ordinary photographic film, which darkens onexposure to radiation and is routinely used in thetbrm of film badges for measuring the cumulativeamount of exposure received by people who workwith sources of radiation. Other types of detectors.such as Geiger counters, ionization chambers andproportional counters. are used to detect the presenceand measure the intensity of atomic radiation. Theseinstruments can detect the presence of extremelysmall amounts of radioactive materials. Radiationdetection is also very sensitive in its ability to identify
36
specific radioactive substances. This is possiblebecause every species of radioactive atom has acharacteristic pattern of radioactive decay.
Units for Measuring Radiation Exposure
The roentgen is the unit of exposure related tothe number of ion pairs produced in air by x-raysand gamma rays. It is the amount of such radiationrequired to produce ions carrying a standard chargein a standard amount of air. The roentgen can bemeasured directly since the electric current producedcan be measured with an ammeter.
The radiation absorbed dose (rad) indicates theamount of energy deposited in material by any typeof radiation. It is a measurement of not only ionpairs, but of all energy deposited. A rad is a verysmall unit. For example, one rad is equal to theenergy required to raise the body temperature by.000002 degrees Farenheit.
The roentgen equivalent man (rem) is the unitof dose equivalent. It is a measure of not only energydeposited, but also the resulting biological effects.
For instance, suppose 500 rads of gamma raysproduce a certain change in a tissue, and 50 rads ofalpha particle radiation produce the same change. Wethen would say that the alpha radiation was 10 timesas powerful in causing this change. In other words,the alpha radiation would have a quality factor of10 as compared to the gamma ray.
We can use the formula rems = rads x qualityfactor to convert to rems. Using our example, thequality factor for gamma radiation is 1. Therefore500 rads multiplied by a quality factor of 1 gives500 rems. For the alpha radiation, 50 rads multipliedby a quality factor of 10 gives 500 rems. The numberof rems is thus the same for the two types ofradiation which produced the same biological effect.
Since radiation protection deals with theprotection of people from unnecessary radiationexposure, regulations and recommendations areusually written in terms of rems. However, it is oftendesirable to work with smaller units, so millirem(mrem), which is one-thousandth (.001) of a rem, isoften used. For example, the maximum permissibleexposure allowed for a radiation worker is 5 rems,or 5000 mrcm, per year.
To summarize the units of radiation exposure,a roentgen refers to the ions produced in air by x-and gamma radiation. A rad refers to the energydeposited in any material by any ionizing radiation.A rem refers to the results of that energy depositedin tissue.
Sources of Radiation
As we have mentioned, humans have alwaysbeen exposed to radiation. This natural orbackground radiation comes from many sources.
One source of natural radiation is the highenergy cosmic radiation from the sun and stars. Thisradiation interacts with our atmosphere to producea shower of charged particles.
Another source of natural radiation isnaturally-occurring radioactive isotopes. For example,natural radioactive materials like uranium andthorium are widely distributed in soil and rocks. Themore energetic radiations from these radioisotopesserve to irradiate us continuously. Also, a small partof all potassium is radioactive potassium-40, and asmall part of all carbon is radioactive carbon-14. (SeeFigure 18) This radioisotope is constantly beingformed in the upper atmosphere by the interactionof cosmic radiation on atmospheric nitrogen. Thesenaturally-occurring radioisotopes add about 50mrem/year to our exposure.
The amount of radiation dose received fromnatural radiation varies according to location. Forexample, the cosmic radiation dose doubles fromabout 40 mrem/year to about 80 mrem/year whenmoving from sea level to 10,000 feet, as whensomeone moves from Philadelphia to a town high inthe Rocky Mountains. This exposure increases by 15per cent moving from the equator to a geomagneticlatitude of 50 degrees.
Similarly, the dose from radiation in rocks varieswith location. Moving from one part of New YorkCity to another may add an additional 1:5 mrem/yeardose because of this difference in rock.
Even the type of house a person lives in affectsthe amount of background radiation received. Thebackground received by a person living in a woodenhouse is about 100 mrem/year. If they move to abrick and concrete house, they may get as much as300 mrem/year because of higher radiation levels in
37
the earthen-type building materials.
Several sources of man-made radiation add tothe average dose that everyone receives. Mostsignificant is the dose from medical and dental x-rays.A small amount of radioactivity is also received fromfallout from weapons testing and from nuclearreactors. These are summarized in Table 7. Theradiation doses in this table are genetically significantdoses, which means that they estimate the potentialgenetic effects of radiation on future generations.
To put this into perspective: if you had to makethe choice of the best way or group of ways to reduceradiation exposure, what would you decide?
1. Prohibit people from living in brick and concretehouses. Require everyone to live in wooden houses.This would save 50 to 200 mrem/year for each personnow occupying brick and concrete houses.
2. Work to reduce our medical x-ray exposure fromthe current 36 mrem/year.
3. Prohibit people from living in Manhatten.Require them to move to Queens, at a saving of 15mrem/year for each person.
4. Require reactors to reduce their radioactiveeffluents by a factor of ten, saving each of us 0.009to 0.09 mrem/year.
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Student Activity: Compute Your Own Radiation Dosage
We have seen that radiation is all about us and is pars of our natural environment. In this exercise youwill get an idea of the amount you are exposed to every year. The unit of radiation used here is the millirem.
Common Source of Radiation Your Annual Inventory(mrem/year)
WHERE YOU Location: Cosmic radiation at sea levelLIVE Add 1 for every 100 feet of
elevation where you live
WHAT YOU EATDRINK ANDBREATHE
HOW YOULIVE
HOW CLOSE YOULIVE TO ANUCLEAR PLANT
House construction: Wood 35Concrete 50Brick 75Stone 70
Ground (U.S. Average)
Water and food (U.S. Avaage)
Air (U.S. Average)
J et Airplanes: Number of 6000-mile flights x 4
Radium Dial Wrist Watch: Add 2
Television Viewing:Black and white: Number of hours per day x IColor: Number of hours per day x 2
Compare your dose to the U.S. Average of 200 mrem/year
39
40
25
5
Factors Which Influence Radiation Effects
Radiation effects are not dependent solely onthe amount of radiation received. Other factorsinfluence the biological effects of radiation.
Dose Rate Effects
The rate at which a radiation dose is receivedis an important factor in determining its effect. Thisis because living tissue is not inert. As soon as damageis produced, healing will begin. Thus if a particulardose is delivered over a long period of time, it ispossible that repair may keep up with the damageso that no detectable change would be produced. Onthe other hand, if the same dose is delivered all atonce, a noticeable reaction may result.
Knowledge of the effects of radiation hasgenerally resulted from data on large doses receivedin a shorn time. These sources include Hiroshimasurvivors. ,..tims of radiation accidents and patientsreceiving radiation therapy. However, most humanexposure is in the form of low doses and low doserates To see the biological effects of this type ofradiation. one would have to observe large groups ofpeople over many generations. Because of thisdifficulty. it has been the general practice to predictthe results of the low doses and low dose rates onthe basis of high dose and high dose rate data.
Furthermore, in order to be conservative inestimating radiation effects, it is assumed that someinjury results from any exposure to radiation.According to the International Committee onRadiation Protection (IRCP): "The objectives ofradiation protection are to prevent acute radiationeffects. and to limit the risks of late effects to anacceptable level. For purposes of radiationprotection, any exposure is assumed to entail a riskof biological darnage." It should he stressed that thisis not known to be the case. There are certainly levelsof radiation that produce no detectableeffects-background radiation and routine diagnositcx-rays. for example. But the most conservativeassumptions are used to insure maximum protectionlot the population.
Age of the Individual
The age of the exposed individual can greatlyaffect his sensitivity to radiation. When organs aredeveloping before birth, the sensitivity is high.
40
because differentiating cells and cells undergoingrapid division arc more easily damaged. Similarly, inthe period between birth and maturity, high rates ofcell division and possible further differentiation makea child more sensitive to radiation exposure. An adultis more resistant to radiation effects. This exposure,however, may give rise to genetic effects in children.In a person beyond the reproductive age, these-enetic effects are not important. Similarly, for olderpersons whose life expectancy has decreased,radiation effects which might appear only after a longtime (for example tumor induction) would not beas significant as with younger people.
Part of Body Irradiated
If the upper abdomen is irradiated, the radiationeffects are more severe than if a body area of similarsize elsewhere were exposed to the same dose. Thisis because of the presence of vital organs in the upperabdominal area. The ICRP has maderecommendations for the general public for doselimits to different parts of the body. These rangefrom a low of 500 mrem/year to the reproductiveorgans and red bone marrow to a high of 7500mrem/year for the hands, fosearms, feet and ankles.
Extent of Body Irradiated
Irradiation of a small part of the body surfacewill have much less general effect than an equal doseper unit area delivered to the whole body, since theunirradiated port;on of the body can aid in therecovery of the affected portion.
Biological Variation
Although it is possible to determine an averagedose which produces certain effects, individualresponses will vary from those of the average. Forinstance, it required a dose of about 600 rads in asingle exposure to kill half a group of rats within30 days. On the other hand, some of these rats diedafter 400 rads and some were still living after 800rads. This is biological variation.
Internal Radiation
Most of what has been said so far aboutradiation effects has been in terms of external dose.that is radiation received from outside the body.When radioactive materials are taken into the body.whole body effects may occur. Radioactive material
may enter the body through food, water or air, butthe most common source of significant levels ofradioactive materials inside the body is nuclearmedical techniques. These radioactive materials movethrough the body in the same manner as thenonradioactive materials. They are also eliminated inthe same manner, and constantly become weakerthrough radioactive decay.
With external radiation, the dose to anindividual can be reduced with shielding, distance orshortening of the exposure time. When theradioactive source is inside the body, reduction ofthe dose is not so simple. Also, the amount ofinternal radiation necessary to bring about a giveneffect is much smaller than that required from anexternal source. This is because the internalradioactive material actually becomes a part of theliving tissue.
The effect of internal radiation depends onseveral factors. One of these is the sensitivity toradiation of the organs or tissue to which the materialgoes. Another factor is the type of energy of theradiation being emitted. This determines the qualityfactor. The physical and chemical form of theradioactive material also helps to determine itseffects. A major factor in the effect of internalradiation is the effective half life (T. ) of theradioactive material. This is the time it takgs a personto reduce the amount of radioactive material toone-half the original amount. The effective half lifeis in turn determined by the biological half life (TB),which is the time it takes the body to removeone-half of the radioactive material; and the physicalhalf life (Tp), which is the half life of the radioactivematerial as defined in Chapter 3. These three termsare related by the exp. ,sion
I/TE = 1/Tp + 1/TB
Thus a long-lived radionuclide emitting alpha particlesand desr osited in bone would be more harmful thanan equivalent amount of a she rt-lived rauionuclideemitting gamma rays which are no readily absorbedinto tissue and do not concentrate in any organ.
Radiation Effects
Biological effects of radiation are divided intotwo general classes. Somatic effects are thoseobserved only in the person who has been irradiated.Genetic effects are those seen in the offspring of the
41
person who has been irradiated.
Somatic Effects
1. Cellular response
The first event in the absorption of ionizingradiation is the production of excited atoms and ionpairs. When these are produced in the chemicalsystems of a cell, new and possibly harmful chemicalsare produced as the original chemical structure of thecell is disturbed by the radiation. Thus toxic materialsmay be produced. Furthermore, if the radiationaffects chromosomal material within the cell nucleus,cell division may be affected. Thus a cell may respondto irradiation by chromosomal changes, cell deathbefore division, failure to specialize, failure to dividecompletely or slowing of the division rate. Inaddition, some cells will be unaffected by theradiation.
The cellular response to radiation is determinedby a number of factors. Among these are the stageof specialization of the cell, its activity and itsdivision rate. These factors would partially accountfor the sensitivity to radiation of the embryo ascompared to an adult. In the embryo, a -small groupof cells eventually will specialize or form an organ,so these cells are especially radiosensitive.
These factors also help to make radiationtherapy possible. A patient with cancer, for example,receives a number of exposures giving him a largetotal radiation dose. Through the phenomenon ifrepair following radiation exposure, the cells beginto repair the radiation damage between exposures.However, the rapidly dividing cancer cells have agreater chance of being destroyed because they aremore frequently in the radiosensitive stages of celldivision.
2. Organ sensitivity
The radiosensitivity of organs and tissuesdepends on cell multiplication. In the lining of tillgastrointe3tinal tract, for example, some of the cellsare mature. These are continuously being discardedand replaced by new cells produced nearby. If a highdose of radioactivity is received, these rapidlydividing cells will be severely decreased in number.If the dose is not too high, the cells still living willbe able to replace those destroyed.
If a large dose is given to a small area of thebody, the general and local effects will depend onwhich organ was irradiated. For instance, a largeradiation dose to an arm will very likely causedetectable changes in the arm. But it will not resultin death or severe damage to the blood-makingsystem because the majority of this system was notexposed to the radiation. On the other hand, amoderate dose of only 30,000 mrads to the smallreproductive organs can result in temporary sterility.
3. Total body doses
The effects of large sudden whole body dosesof radiation are called the acute radiation sicknesssyndrome. This syndrome consists of nausea,vomiting, general aches and pains and possibly adecrease in the number of white cells. Localizedphonomena such as reddened skin or loss of hair maybe produced. Larger doses cause weakness, drasticdepression of all blood elements and possiblysterility. Exposure of the eyes may cause cataracts.At still higher dose levels, death will probably occur.
Table 8 shows the probabie results of variousmassive whole body doses of radiation received overa short time period.
Table 8
Effects of Large Whole-Body Doses of Radiation
Dose
10,000,000 mrem
1,200,000 mrem
600,000 mrem
450,000 mrem
100,000 mrem
Effect
Death within hours due todamage to central nervoussystem
Death within vveral daysdue to damage togastrointestinal system
Death within several weeksdue to damage toblood-forming organs
50-50 chance of deathwithin 30 days
Possible temporaryimpairment, but probablerecovery
It has been shown in animals that high radiationdoses cause bodily changes that lead to effects similar
k
to the aging process. It is obviously difficult to obtainsuch data for humans, but it is probable that somedegree of life shortening may occur following highdose exposure.
The effects of long-term, low dose rate exposuremust be predicted, since data on such exposure andits effects are nearly impossible to obtain. Theproblem is complicated because such low dose effectsgenerally develop years after the exposure. Also, thesame effects may be caused by something other thanthe radiation. For example, cancer ani leukemia maybe long-delayed consequences of a single largeexposure! and they may also follow chronic exposure.But they are by no means an inevitable result of anyform of human exposure to radiation.
Much recent attention has been directed at theincreased incidence of lung cancer in uranium miners.This may be due to the inhalation and deposit ofthe decay products of radon in the lining of the lung.Radon is a naturally-occurring radioactive gasresulting from the decay of uranium and thoriumradioisotopes.
Genetic Effects
The term genetic effects refers to the productionof mutations, which are permanent transmissiblechanges in the characteristics of an offspring fromthose of its parents.
Mutations occur in all living organisms. Theymay occur of their own accord, apart from anyknown alternation in the environment. Whatever theirorigins, most mutations are undesirable. Everyindividual has some of these undesirable mutations.
Radiation-induced mutations are divided intotwo classes: gene mutations and chromosomalabnormailities. Most radiation-induced alterations aregene mutations. These tend to be recessive. In otherwords, the effect of the mutation is not seen in theoffspring unless the altered gene is carried by bothparents. Even though the mutation may not be seenin the first generation offspring, it makes themslightly less fit.
Chromosomal abnormalities includechromosome loss and chromosome breaks. Theseeffects are more severe, art.! the result is usually deathof the embryo before birth. This type of geneticeffect happens much less frequently than does genemutation.
42
The increase in genetic damage to be expectedfrom radiation is sometimes discussed in terms ofdoubling dose. This is the dose that would eventuallycause a doubling in the rate of gene mutations thatoccur spontaneously.
In the United States at the present time, about100 million children are born in a generation. Ofthese, about two per cent will have genetic defectsas a consequ,,ia of spontaneous unavoidable geneticchanges which were passed on to Vie individuals fromall their ancestors. If a doubling dose of radiationwere applied to the population for the present andall future generations, this would eventually lead toa gene mutation rate of four per cent. It wc...ld takeon the order of 10 generations to reach the four percent rate. The doubling dose taken by the NationalAcademy of Sciences report, "The Effects onPopulations of Exposure to Low Levels of IonizingRadiations," is estimated to be 40 rads (40,000mrads) per generation. In other words, if the averagedose to the reproductive cells of the individuals ofthe population were a total of 40 rads fromconception to age 30, or 1.3 rads per year abovebackground for every generation, after about 10generations the rate of impairing mutations wouldgradually increase so as to eventually double fromtwo per cent to four per cent. This amount ofradiation is far above that obtained from anyman-made source currently in operation. (See Table7)
Non-Human Biological Effects
In the earthly environment, hundreds ofthousands of species of plants and animals have beenidentified. It is reasonable to expect that a wide rangeof sensitivities to radiation would he seen in this greatvariety. While radiation protection guides are writtento protect us, much of the data upon which testguides are based was derived from animalexperiments.
The basic conditions that tend to predictradiosensitivity in humans, such as cell division rateand ag are applicable to all other life forms as well.However, there is a wide range of variation amongspecies. The more complex the organism. the moreset.;tive it is to radiation effects.
A number of types of organisms have beenknown to reconcentrate radioactive materials in theirbodies. An example is the case of shellfish such asoysters and clams. These organisms can reconcentrate
43
certain radionuclides up to 100.000 times the levelsfound in the water in which they live. Thisreconccntration does not appear to affect thewell-being of the animal, but people who u4; theseshellfish as their sole source of food could receivea significant fraction of their maximum permissibledose in the process. For this reason, edible shellfishliving near the outfall of a iucierit plant are includedin the environmental surveillance program. Thisreconcentration ability makes the shellfish a goodmonitor for cross-checking radioactive discharges.
Radiation Effects from Nuclear Power Plants
What is the risk of harmful radiation effectsfrom nuclear power plants? To quote Lauriston S.Taylor of the National Council on RadiationProtection and Measurements, "There is a
considerable region of radiation exposure aboutwhich we have very little positive knowledge. Thisis in the region of doss s of one or two or even afew rads, delivered all a! once and not repeated toofrequently; larger doses, sat' up to ,10 or 20 radsreceived essentially all at once but 12rely. if everrepated; and finally exposures at very low levels andat low dose rates, say at naillirads or less per day,but persisting over long periods and totalling (milsome five or ten rads distributed over a lifetime.
It is particularly this latter condition which isof concern to the public with the use of nuclearreactors, and it is this range and kind of exposureupon which we have little positive and directknowledge. But It is in the same range of exposurethat we have made a tremendous effort of attemptingto discover effects, with all results so Jar beingconvincingly negative. This inability to find effectsis itvlf extremely important, but it must herecognized that the test samples may not hare beenlarge enough The levels of dose about which thepublic is concerned in the nuclear power industry areat the most a few thousandths of a rad per .year.and more likely less than a thousandth The upperdose limit to the population jiff all man-maderadiation is 700 times less than the lowest thise ofgamma rays which has been statistically shown tocause leukemia.
At the same time the population dose limit isat least some hundred times higher than the averagedose to the population from all the reactors expectedto be installed between now and the rear :Wm,assuming no improvement in gner pr,,ietbnitechniques."
Perhaps the only problem is that we do notknow how to measure the effects of such very lowdoses of radiation, because they are too small orhappen too infrequently to be measured by anypresent techniques. This means that if the effectscannot be measured by any of the fairly sophisticatedmethods that we do have available today, thepotential hazardif it exists at allis sufficiently smallso that there is time to further study and analyzethe problem without a serious risk.
However, this very fact of being unable to detectany effect. accompained by an unwillingness to saythat there is no effect at all, has led us into adilemma. In order to avoid setting standards whichwould expose the public to unnecessary radiation.and what future knowledge may show to be
dangerous amounts of radiation. the National Councilon Radiation Protection and Measurements has setexposure limits based upon the following very
cautious assumptions:
1. There is a single, linear dose-effect relationshipfor the effects of radiation from zero dose withno effect to the known effects of high leveldoses.
2. There is no threshold of radiation below whichthere is no effect.
3. All doses received by an individual are
additivethat is, their effects add up.
4. There is no hi.'logical recovery from the effectsof radiation.
All available evidience indicates that several ofthe above assumptions are simply not true. but inthe interest of safety we assume that they are, underthe conservative philosophy that it is far better tobe oversafe than to be sorry at some future date.
The radiation protection guide or maximumpermissible dose to the general population arrived atas a result of these assumptions is presently set at170 mrem/year above natural background. This figuredoes not include an individual's radiation dose frommedical procedures. The NCRP does not attempt anyregulation or limiting of radiation exposure fornecessary diagnostic and therapeutic purposes. Theydo make recommendations to reduce that part of theexposure which does not contribute to the efficiencyof treatment or diagnosis.
44
To keep the dosage which we may expect toreceive from nuclear power plants in perspective, themaximum exposure to the public from the combinedeffects of all nuclear power plants expected to beconstructed by the year 2000 will not be a total dosegreater than 10 millirems.
The Atomic Energy Commission insures thatrelease of radioactivity from nuclear power plants isas low as practicable. Proposed guidelines for definingthese as-low-as-practicable levels would keep
radiation exposure of persons living near nuclearpower stations to less than five per Cent of theaverage natural background radiation. Such exposurewould be about one per cent or less of the federalradiation protection guides for individual members ofthe public.
BIOLOGICAL EFFECTS OF FOSSIL FUELEDPOWER PLANTS
Biological effects of fossil fuels come mainlyfrom the air pollution which is a result of the burningof such fuels. Fossil fueled plants produce airpollution in the form of oxides of sulfur andnitrogen, carbon monoxide. unburned hydro-carbonsand partii'ulates in the form of fly ash. Table 9 showstypical amounts of pollutants released to the
environment by a 1000 megawatt power station.
Table 9
Emissions from Fossil Fueled Generating Stations
Pollutant Annual Emissions (Millions of pounds)Coal Oil Natural Gas
The figures in Table 9 assume use of 2.3 milliontons of coal containing 2.5 per cent sulfur, 460million gallons of oil containing 1.6 per cent sulfurby weight, and 68 billion cubic feet of gas. Theyalso assume a nine per cent ash content for the coalwith 97.5 per cent fly ash removal efficiency. Noother pollution control equipment is assumed indetermining these figures.
When talking about the effects of air pollutants,the term parts per million is frequently encountered.This term is an expression of the concentration ofone material within another material. For example,it is used to express the concentration of a gaseousair pollutant such as sulfur dioxide in another gas,air. One part per million (ppm) means one part ofthe pollutant in one million parts of air.
Sulfur Dioxide
Sulfur dioxide (S02) is an air pollutant of majorconcern, since power plants emit more of it than anyother pollutant. It is a colorless gas produced whenfeels containing sulfur are burned. Most people cantaste it at concentrations greater than 1 ppm, and ithas an irritating smell at concentrations above .7ppm. In the environment sulfur dioxide is transormedto sulfur trioxide or to sulfuric acid and particulatesulfate salts. These conversions depend on thepresence of moisture in the air, on the presence ofdusts and smokes and on the intensity and durationof sunlight.
The health effects of the oxides of sulfur arerelated to injury to the respiratory system, whichincludes the lining of the nose, the throat and lungs.Laboratory studies have shown that sulfur dioxideconstricts the bronchial tubes of the lungs ofexperimental animals.
In general, the laboratory work performed thus
45
far is not entirely relewant to the real environment.In the real environment, the concentrations of awhole spectrum of pollutants are constantlychanging. The level of moisture in the air is changing.The intensity of sunlight varies. The temperature risesand falls. Although it is very difficult to reproduceall these changes in the laboratory, valuableinformation on sulfur dioxide has been gathered. ithas been shown, for instance, that it is not wise tomeasure only one pollutant in the air, and then usethat data alone to describe the quality of the air.The interaction of the various pollutants can haveeffects different from those produced by theindividual pollutants. For example, sulfur dioxidealone acts as a bronchial restrictor that can causebreathing problems, especially for those who alreadyhave a breathing impairment. Certain aerosols suchas iron, manganese or vanadium, which may hepresent in particulate matter, react with the sulfurdioxide to form sulfuric acid. St.lfuric acid is a moresevere irritant to the bronchial system, and canpenetrate deeper into the lungs. Therefore,combinations of particulate matter and sulfur dioxideare potentially more damaging than either alone.
Another way to study the problem of the oxidesof sulfur is the science of epidemiology. This sciencedeals with the study of the movement of an injuryor disease through a population after the injury ordisease begins to be noticed. The epidemiologist mustthink of all the possible causes for the disease in thegroup of people and then carefully eliminate all thecauses except one. These epidemiological studies lackthe controlled conditions of the laboratory, Mt theyare carried out in the real life environment. Frontthese studies, it has been clearly concluded that theoxides of sulfur in the air have an effect on the healthof a group of people. and that the severity of theeffect is directly related to the degree of pollution.
The results of some epidemiological studies ofthe effects of sulfur dioxide are listed Table 10.
Location
England
England
London
London
London
London
Rotterdam
New York
New Y ')rk
Chicago
Particulates
Table 10
Effects of Sulfur Dioxide
SO2 Concentration (ppm) Effects
0.040 This annual mean produced an increase indeath from bronchitis and lung cancer, withcigarette smoking, age, occupation andclass taken into consideration.
0.046 This long-term level increased frequencyand severity of respiratory diseases inchildren.
0.20 This one-day average accentuated symptomsin persons with chronic respiratory disease.
0.25 Rise in daily death rates after abruptrise to this level.
0.35 Distrinct rise in deaths with concentrationover this level for one day.
0.52 Death rate appeared to rise 20 per centover baseline levels.
0.19 Apparent increase in total mortality aftera few days at a mean concentration of thislevel.
0.007 Rise in upper respirator infections andto heart disease complaints during the 10-day
0.86 period.
0.5 Excess deaths were detected after 24 hoursat concentrations over 0.5 ppm.
0.25 This one day average increased illness inolder patients with severe bronchitis.
pollutants in the air.
Particulates are primarily mineral ash plus 0.5to 5 per cent unburned fuel.
The effects of particulate air pollution on healthare related to injury to the respiratory system. Thedamage may be due to the particulate itself, or tothe gases like sulfur dioxide which are carried on theparticles.
Here again it is difficult to separate the effectsof the particulate from the effects of other known
46
In Table 10 on effects of sulfur dioxide, in mostof the studies cited, the particulate load in the airwas proportional to the sulfur dioxide concentration.
The 1970 Clean Air Act mandates that standardshe enforced on all pollutants by mid-1975, and thatthe best available means be installed, rather thanwaiting until ideal processes are available. Today,several different types of systems are being used tocontrol the emission of sulfur dioxide and particulate;natter to the atmosphere. One system invob,es the
conversion of sulfur dioxide to sulfur trioxide; thesulfur trioxide reacts with water vapor, and can thenbe condensed as sulfuric acid. Sale of sulfuric acidcan help offset the cost of operating the system.
In this system, hot flue gas is passed througha dust removal system as it leaves the boiler. Thisdust removal system, a combination electrostaticprecipitator and mechanical dust remover, traps morethan 99 per cent of the particulates in the flue gas,preventing their release into the atmosphere. The ash,often referred to as fly ash, can then be collectedand transported to a disposal site.
From the precipitator, the hot flue gas flowsto the second stage of the cleansing process, theconverter. In the converter, a catalyst fosters thechemical change of sulfur dioxide to sulfur tri( xide.The flue gas, now rich in sulfur trioxide, next flowsthrough a heat exchange system, where the gas iscooled.
The final stage of the system is that of actualsulfuric acid production. Acid is condensed in theabsorbing tower, while the flue gas continues to themist eliminator, where remaining small amounts ofsulfuric acid mist are collected. The flue gas, withvirtually all of the fly ash and sulfur dioxide removed,can now be released to the atmosphere.
Oxides of Nitrogen
This class of pollutants includes four differentoxides, but most of the studies have been conductedon nitrogen dioxide (NO2). During combustion, thenitrogen gas in air (79 per cent by volume) combineswith oxygen to form nitric oxide. Although theamount of sulfur oxides released by a plant can bereadily calculated, the concentration of oxides ofnitrogen is a function of the temperature of thefurnace, the gas cooling rate, the amount of excessair in the furnace, and the method of firing. Theconcentration is thus difficult to calculate.
Nitrogen dioxide has been significantlycorrelated with increases in respiratory diseases, atmean daily concentrations between 0.062 and 0.109ppm in Chattanooga, Tennessee. Nitrogen oxides alsoplay a significant part in the formation of smog.
Combustion modifications and stack gasscrubbing offer possible control of pollution fromoxides of nitrogen, but no process has yet been
47
proven really effective. Some exploratory work hasbeen reported on simultaneous removal of the oxidesof both nitrogen and sulfur.
Hydrocarbons and Carbon Monoxide
The production of hydrocarbons and carbonmonoxide in power plants is currently overshadowedby their large scale release from motor vehicles. Bothof these pollutants can be reduced by more efficientfuel combustion, reducing them to relatively harmlesscarbon dioxide and water vapor.
Hydrocarbons can react with nitrogen dioxideto become a major cause of smog. They have alsobeen directly linked with an increase in the incidenceof lung cancer.
Carbon monoxide primarily affects personssuffering from poor blood circulation, heart disease.anemia, asthma and various lung diseases.
Radiation from the Burning of Coal
All coal contains a small amount ofnaturally-occurring radioactive materials such aspotassium, uranium, thorium and their decayproducts. Assuming five parts per million ofradioactive material in coal (0.01 pound per ton),then a 1000 megawatt electrical generating plant,burning about 10,000 tons of coal per day, liberatesabout 100 pounds of radioactive materials. Most ofthis radioactive material is contained in the unburnedparticulate matter and ash, but some is released intothe atmosphere as radon gas. Thus the averagecoal-burning plant will release more radioactivity intothe environment than many modern nuclear powerplants. These amounts of radioactivity are well belowestablished radiation levels. No environmental damagehas been detected near such plants due to this releaseof radioactivity, and thus no effort has been madeto date to control it.
HOW SAFE IS SAFE ENOUGH? RISK VERSUSBENEFIT
Technological growth has been tremendous inrecent years. Following closely behind this growthin the advanced countries of the world has been socialand economic benefits. But each advancement hasalso brought about a cost or risk to the people. Boththe benefits and the risks brought about by
technological growth affect the quality of life of the
population. Benefits include higher standards ofliving, better health care and more leisure time. Risksinclude urban problems, pollution. technologicalunemployment and the social stress and strain ofmodern life.
There is no precise definition of "quality oflife," but the identification of several majorcomponents is possible. The passage by Congress ofthe National Environmental Policy Act of 1969 isstrong evidence that most citizens accept theconservation of the natural environment as animportant element of the quality of life. There is alsolittle doubt that relatively full employment and atleast modest affluence for most individuals isimportant to the public. Thirdly, goods and servicesdepending on electric power play a large part inshaping the man-made environment, especiallyindoors where most people spend the majority oftheir time. The typical citizen seriously wantslighting, forced - circulation heating. radio andtelevision, air conditioning and scores of other thingsrequiring electricity.
We cannot demand more benefits from electricpower without accepting the risks, involved in itsgeneration. We have seen some of these risks in thischapterrisg.s from radiation and risks from the fossilfuel pollutants. What must be done is for the publicto assure that through proper regulation andengineering these risks are minimized so that we cancontinue to enjoy the benefits of electricity.
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Chapter 6
WASTES IN THE PRODUCTION OF ELECTRIC POWER
This chapter deals with waste products from thegeneration of electrical energy, other than thosewastes having a direct biological effect, such as theair pollutants discussed in the preceding chapter. Thefirst section deals with the problem of disposing ofwaste heat, since this is a problem shared by nuclearand fossil fueled plants. The next section discussesthe radioactive wastes produced in a nuclear powerplant, and the last section deals with wastes fromfossil fueled plants.
HEAT AS A WASTE PRODUCT
Most of the energy used by humans is providedthrough the process of converting heat energy intoelectrical and/or mechanical energy. The efficiencyof this conversion is limited by natural laws. Modernsteam turbine equipment provi tes probably thehighest efficiency of all the heat engines in practicaluse today, but still between 60 to 70 per cent ofthe total available energy is not used and must bedissipated to the environment as heat.
Several factors make the problem of heatdisposal more difficult for nuclear plants than forfossil fueled plants. First, using high temperatures(1000 to 1100 degrees Fahrenheit) and high steampressures (1800 to 3500 pounds per square inch),today's modern fossil fueled steam-electric plantsattain an overall thermal efficiency of 37 to 38 percent. However, less than half of the presentlyoperating plants attain this thermal efficiency. Theaverage efficiency of all fossil-fueled plants is about33 per cent. Because of certain design criteria, mostcurrent nuclear power plants produce steam at lowertemperatures (500 to 600 degrees Fahrenheit)ind atlower pressures (800 to 1000 pounds per squareinch). Thus their thermal efficiency is somewhatlower, approximately 32 per cent . so they must rejectmore heat. Advanced gas cooled reactors presentlyin the design and testing stage are expected to equalor exceed the thatnal efficiency of the best fossilfueled plants.
Secondly, nuclear power plants are generallybuilt with a larger generating capacity than fossilfueled plants. This means a greater amount of heatto he dissipated at the location of a nuclear power
49
plant.
Finally, nuclear power plants make a greaterdemand on their supply of cooling water than dofossil fueled plants. This is because fossil plantsdischarge about 15 per cent of their waste heat intothe air with the flue gas, with the remaining 85 percent being discharged into a cooling stream of water.Since nuclear reactors do not reject heat by way ofcombustion gases, nearly all of their waste heat isdischarged into the cooling stream.
Methods of Heat Disposal
As previously stated, heat from the combustionof fossil fuel in a boiler or from the fission of nuclearfuel in a reactor is used to produce steam whichdrives a turbine connected to a generator. When theheat energy in the steam has been convected tomechanical energy in the turbine, the "sport" steamis converted back into water in a condenser.
Condensation is accomplished. by passing largeamounts of cooling water through the condenser. Inthe least costly and most widely used method, thecooling water is taken directly from a nearby river.lake, estuary or ocean. The cooling water is heated10 to 30 degrees Fahrenheit-depending on plantdesign and operation and then returned by coolingcanals to its source. Usually only a small fraction ofthe volume of a body of water is used fin coolingwater. Thus the temperature increase is usually lessthan one degree Fahrenheit at points 1000 feet fromthe point of discharge. The body of cooling watereventually loses the heat to the atmosphere. This typeof cooling system is called a once-through system.If the volume of the body of water is not sufficient.the heated water may he critically low in oxygen.and may favor the rapid growth of some aquaticplants. If this temperature change in the coolingwater is excessive, it may cause critical ecologicalproblems. However, if the volume of cooling wateris large enough, the temperature change may heneglihible. In more northern areas, it is possible thatincreasing the temperature of the water may actuallybe desirable.
The discharge of heated water into naturalsystems has not produced major problems as yet, butcontinued growth in electrical power production may
well cause damaging environmental stresses to occurin some areas unless heat loss is controlled. Thereare alternatives to the once-through system whichcause less of a strain on the natural waterways. Eachof them involves environmental effects and economicpenalties. The best system for a particular plant musttherefore be decided on a case-by-case basis.
Artificial ponds or lakes can be constructed toprovide a source of water for circulation through thecondensers. These ponds require large land areas forstorage and drainage: a 1000 megawatt plant mightrequire as much as 3000 acres for such a pond. Theseponds will create some local fogging on cold daysdue to the evaporation of warm water from theirsurface.
Waste heat may be transferred to the air throughwet or dry cooling tower systems. In wet coolingtower systems, the cooling water is brought in directcontact with a flow of air, and the heat is dissipatedprimarily by evaporation. The flow of air throughthe cooling tower can he provided by eithermechanical means or natural draft, and make-upwater must he added to replace evaporative losses.Wet cooling towers for a 1000 megawatt nuclearplant may evaporate no to 20 million gallons of waterper day. A comparable fossil-fueled plant wouldevaporate about 14 million gallons. This excess waterburden in the atmosphere may affect local climaticconditions. In cold or humid weather. the liklihoodof fogging and precipitation is increased, and in somecases with cold climates, these towers have createdicing problems on nearby plant structures and roads.
In dry cooling tower systems. the cooling wateris carried through pipes over which air is passed andthe heat is dissiapted by conduction and convectionrather than by evaporation. Dry cooling towers avoidthe problems of fogging and icing common to wetcooling towers, but they require a large' surface areafor heat transfer and the circulation of a largervolume of air. This cuts down the overall power plantefficiency. Dry cooling tower technology has not yetbeen demonstrated in the United States.
Although these alternatives offer relief from apotential thermal effects problem, they do notconstitute a satisfactory answer to the heat problem.The probable answer will be to find a use for theexcess heat and to increase the efficiency of electricalgeneration to decrease the amount of such excessheat.
Research is underway on finding uses for the
50
excess heat from power plants. One study is
investigating the beneficial uses of low grade heat incompatable urban systems. An example is the use ofdischarge heat to increase the rate and effectivenessof secondary sewage treatment processes. Anotherpossibility is that treated sewage effluent may be usedin cooling towers, where the nutrients can be
substantially concentrated by the process ofevaporation. If the evaporated water could becondensed and collected, it could become a sourceof pure water, while the concentrated nutrients couldbe recovered and recycled into the environment.Desalination of sea water mip,lit be accomplished inthe cooling towers, providing pure water andminerals.
Controlled heated water has been found to beadvantageous to a few forms of fish culture,particularly shellfish. Tests demonstrate that it is
possible to extend the growing season for crops byutilizing reject heat in agriculture.
These concepts and many others such as homeheating and cooling are incorporated into the ideaof the Nuplex or Energy Center Complex. It is
envisioned that an entire city would grow upassociated with and complimentary to a nuclearelectric power source. In this city of the future,practically all the reject heat would no longer hewaste heat to he disposed of. but would be a resourceto be used for beneficial purposes.
RADIOACTIVE WASTES
The first point where waste products whichcontain measurable amounts of radioactivity appearin the nuclear power production cycle is with themining and milling of the uranium or thorium ores.These materials are brought to the surface of theearth and concentrated. Radioactive materials whichare not present in commercially valuable amounts gointo tailing piles and milling by-products. In additionto these solid wastes, the mills produce large
quantities of liquid wastes containing low levels ofradioactivity.
These materials require further processing andoften enrichment steps. This results nt more wastescontaining natural radioisotopes.
Fabrication of the fuel elements produces someliquid waste and scrap with low levels ofradioactivity.
Operation of of nuclear power plant produces
solid, liquid and gaseous wastes. The fissionby-products produced by nuclear fuels in reactors areby far the largest source of these wastes in termsof radioactivity. As we have mentioned, more than99.99 per cent of these fission products remainconfined within the fuel elements. Valuable unusedfuel remains in the fuel elements along with theseaccumulated fission products. When it comes time torefuel the power plant, which is done at intervals ofa year or longer, the reactor is shut down and thetop of the reactor vessel is removed. The spent fuelelements are moved to a storage vault or pool wherethey remain for several months until the radioactivematerials with short half lives have had a chance todecay. By the end of this time, nearly all of thegaseous fission products have lost their radioactivity.The fuel elements are then loaded into ruggL dly-builtlead-shielded steel containers for shipment by truck,rail, or barge to a plant where they will be chemicallyprocessed to recover the unfissioned uranium and theplutonium formed during reactor operation.
In the repocessing plant, the tubes which makeup the fuel assemblies are chopped into smallsegments, and the fuel pellets are dissolved in strongacid. Then the fuel and fission products arechemically separated. It is at this point that highlyradioactive waste is produced. These liquid wastespose the most severe hazard and the most complextechnical problems in radioactive waste management.
Principles of Radioactive Waste Management
There are three basic principles which arebroadly applied in waste management.
Delay and Decay
The first of these principles is "delay anddecay." Radioactive materials with reasonably shorthalf lives are retained at the site where they aregenerated until their natural decay rate has causedthe radioactivity to dissipate. This is generally aperiod equal to about ten half lives of the particularradioisotope. It would be convenient if there weresome method to change long-lived radioisotopes intoshort-lived radioisotopes or nonradioactive material.But the half lives of radioisotopes are not responsiveto outside influences. Each isotope decays at its ownparticular rate regardless of temperature, pressure orother chemical and physical processes Actually. sinceallowing radioisotopes to decay naturally is the onlycurrently practical means of eliminating theirradioactivity, any other method of waste handling
51
must be considered to be an intermediate step leadingfinally to disposal by decay.
Dilute and Disperse
The second principle of radioactive wastemanagement is "dilute and disperse." Wastes ofappropriately low radioactivity may be reduced topermissible levels for release by dilution in air orwaterways. Wherever materials are to be released tothe environment, the amount of radioactivity thatcan be safely dispersed is determined separately foreach specific radioisotope. Such release is carefullymonitored and controlled.
Concentrate and Contain
The third radioactive waste managementprinciple is "concentrate and contain." Radioactivewastes can be concentrated and stored in controlledsites. The volume of the stored material would heprohibitively great if it were not first concentrated.
The choice of a disposal technique depends onthe nature of the waste: its degee of radioactivity,half life and form.
Gaseous Waste Management
The mining, milling and fabrication of uraniuminto fuel elements produces airborne radioactivityfrom natural radioisotopes. This typically occurs inlow concentration, and specialized ventilation of thework area gives adequate protection. Air dischargedfrom mine ventilation e:vstems usually containsappreciable amounts of radon-222 and its decayproducts.
The generation of gaseous radioactive wastes atnuclear power plants varies in composition for eachtype of reactor, but these wastes can be effectivelymanaged. In general, gaseous wastes are held for anappropriate period of decay, then filtered andreleased under controlled conditions through a highstack. Since these gases are a great deal more densethan air, high stack discharge is desirable to preventlayering and accumulation at ground level. The filterswhich are used collect radioactive solid particles.Specially-treated charcoal filters may he used toremove radioactive iodine. The release of radioactivegases from operating nuclear facilities has beensubstantially below limits prescribed by applicableradiation standards.
Gaseous wastes are produced at fuel reprocessing
plants. Various scrubbers. filters and absorptionsystems are used before these gases are released tothe environment through high stacks fitted withmonitoring equipment to register level ofradioactivity and rate of flow.
The radionuclide krypton-85, with a 10 yearhalf life, has been studied especially in connectionwith its release in gaseous wastes. The contributionof krypton-85 to radiation doses in the vicinity ofa nuclear power plant is negligible, since it is a fissionproduct and is almost totally retained in the fuelelements until their reprocessing. It is a part of thegaseous waste from the reprocessing plant. Theradiological effects, both local to the reprocessing ziteand on ,, worldwid, basis, of the release ofkrypton-85 have been considered. The conclusion isthat it will not pose a significant problem until wellinto the 21st century. Cryogenic (extremely lowtemperature) absorption methods to removekrypton-85 are being developed, and should solve theproblem before it becomes significant.
Liquid Waste Management
Uranium mines and ore mills produce relativelylarge quantities of low-level liquid wastes. Theserequire minimal treatment before being released intothe environment. Fuet fabrication plants producesmall amounts of low-level acid wastes which arediluted,neutralized. stored to permit decay and thendischarged to waterways.
In a typical water cooled reactor power plant.there arc two sources of liquid waste: the reactorcoolant itself and drainage from supportinglaboratories and facilities. Often these wastes, whichare usually or a low level of radioactivity, arepermitted to decay. and then are diluted anddischarged to waterways. When necessary. theradioactive liquids undergo treatment by systemssuch as evaporators or ion exchangers. No liquidwastes are released into the ground at reactorinstallations, and the amount of radioactivity releasedto the waterways is carefully monitored and
Fuel reprocessing plants are the source of highlyradioactive liquid wastes. Processing the used fuelleaves a concentrated liquid waste which containsmore than 99 per cent of the radioactive substancesfrom the spent fuel elements. Currently this residueis being stored in underground steel tanks at the
52
reprocessing sites. Nearly 25 years of experience,primarily with wastes from the nuclear weaponsprogram, has demonstrated that this tank storage issafe and practical. But technology for solidifyingthese liquids has been developed, and the AEC nowrequires that they be converted to a more stable solidform. Under this procedure, the highly radioactiveliquid wastes are stored in carefully builtdouble-walled tanks at the reprocessing plant formaximum of five years to allow many of theheat-generating isotopes to decay and make furtherprocessing easier. The liquid waste must be solidified,and then the solid material encapsulated in sealed,manageably-sized stainless steel containers forshipment to a federal repository This shipment mustbe accomplished within ten years from the processingof the fuel, The most promising tong-term controlmethod for these solidified wastes seems to be storagedeep underground in stable geological formationssuch as salt mines or granitic bedrock. Pending a fullsafety evaluation and acceptance of such a geologicalrepository, extended storage will be provided in asurface repository. All necessat) technology is
available for constructing, maintaining andmonitoring these shielded storage facilities, and thisis the approach that the AEC will follow to acceptand manage the high level rauioactive wastes to bedelivered in the early eighties,
It has been estimated that by the year 2000.77 million gallons of high-level liquid wastes wouldhave been generated by the civilian nuclear powerprogram if it had not been for the regulatoryrequirement on solidification. Solidification will
reduce this volume, and the total amount of solidifiedhigh level waste accumulated by the end of thecentury is expected to be about 500,000 cubic feet.This volume would cover one football field to aheight of just over 10 feet.
There is growing interest in internationalcooperation in high-level radioactive wastemanagement. In 1972 the United States participatedin meetings of the Nuclear Energy Agency (formerlyEuropean Nuclear Energy Agency) and theInternational Atomic Energy Agency on high-levelwaste management. It appears that the first order ofbusiness is to agree on the degree of protectionneeded for these wastes, and then to evaluate thevarious storage concepts. The operation ofinternational high-levet waste repositories would hethe next logical subject of discussion.
Solid Waste Management
Solid refuse from mining operations has such alow level of radioactivity that it is usually piled nearmine portals. Solid refuse from ore refining mills,called tailings, arc usually held in controlled areas toprevent dispersal to the environment.
Solid wastes from nuclear power plants are onlymoderately radioactive. They consist mostly ofresidues from filtering systems and evaporators andof contaminated equipment and materials. Thesematerials are packaged as required by transportationsafety regulations, and shipped to special burialgrounds. These burial grounds are on state- orfederally-owned land, and are subject to either federalor state regulations. The solid wastes are generallyburied in unlined pits and trenches. Several feet ofearth are placed over these pits or trenches so thatradiation exposure to workers at the burial site, orto th ; public at the nearest possible point ofapproach, are well within the applicable regulatorylimits.
No high-level solid wastes can be sent to suchburial grounds. High-level solid waste, after a limitedperiod of storage at a fuel reprocessing site, must besent to a federal repository.
Waste Management for Breeder Reactors
Since breeder reactors are important in thelong-term energy picture, a few comments on theirradioactive waste management aspects are pertinent.Breeder reactor fuels will be irradiated to a higherdegree than light water reactor fuels, and reprocessingplant wastes may have a higher radioactivity contentper unit volume. This might require longer interimstorage for decay of short-lived activity or moreshielding: however, these are differences in degree andnot in kind of waste, so that new basic technologywill not he required. The use of metallic sodium asa reactor coolant will require the expansion ofpresently existing sodium safety technology to thehandling of contaminated solid wastes generatedduring breeder reactor repairs and maintenance. Thepotential exploitation of low-grade uranium (andpossibly thorium) deposits for breeder reactorprograms may generate large volumes of mill tailingscontaining very low concentrations of radium. Thesecan he stabilized to preclude air and water pollutionby methods in use today.
53
WASTES FROM FOSSIL FUELED PLANTS
Other than a small amount of air pollution andthe thermal effects which have already been
discussed, gas fueled electrical generating stationsproduce little in the way of waste products.
In onshore oil production, nearly three barrelsof brine, which is pumped out of the ground withthe oil, must be disposed of for every barrel of oilproduced.
Coal is responsible for large amounts of wasteproducts. Mention has already been made of the largeland areas disturbed by mining. If these areas are notreclaimed, they must be considered waste. Largequantities of wastes are generated during the washingof coal to improve its quality. Over 62 per cent ofall coal mined is washed, producing 90 million tonsof waste annually. These unsightly piles of wastesometimes ignite and burn for long periods, creatingair pollution. Rainwater leaches salts and acid fromthe piles and can contaminate nearby streams.
Utilization of coal also products solid waste inthe form of ash and slag. About 30 million tons
of these materials are collected each year in additionto that discharged into the atmosphere. Over the 35year life of a 1000 megawatt coal-burning powerstation, it would produce enough ash to cover afootball field to a height of about three-quarters ofa mile. Some of this ash is being used, for exampleto make cinder blocks, but other uses need to hefound for these vast amounts of waste which arebeing generated.
Chapter 7
PLANT SITE CONSIDERATIONS
Power plants have traditionally been located onthe surface of the ground, either near the source ofthe fuel or near the urban market and majortransmission lines. Such sites were selected foreconomic reasons, without reference toenvironmental protection. We are now becomingaware of the need for more care in the choice ofpower plant sites, and the environmental impact ofany proposed power plant must be carefully assessedbefore it can be built. There are several criteria forpower plant site selection. Most of these apply toboth fossil fueled and nuclear plants, although someapply only to nuclear plants.
SITE ACCESS
It must be possible and economically feasibleto bring construction equipment and power plantmachinery to the proposed site. Some of theequipment that must be brought in is very large, suchas the massive generators and, in the case of a nuclearplant site. the reactor and containment vessel. Aready access to the site is highly important. and oneof the first factors considered after the decision ismade on plant type and general location.
GENERAL ECOLOGY
Ecologyis that branch of science that deals withthe inter-relationships between all living things andthe environment. A complete understanding of all ofthe environmental problem is virtually impossible.Nevertheless, some reasonable level of understandingmust be reached so that future power facilities canbe sited and operated without excessive damage tothe environment. The following ecological researchis critical to the solution or power plant sitingproblems.
I . Improved techniques must be developed todetermine the health and age of ecosystems so thatwe can predict accurately the changes which mayresult in any given ecosystem through even a slightalteration of the environment.
2. Certain animals and plants may serve aspollution indexes: that is. they indicate the presenceof certain pollutants in the environment. Theseshould be monitored.
54
3. Cumulative effects on ecosystems in distantareas must be watched closely. A distant ecosystemmay actually be the critical system upon which tobase pollutant release rates. For example, theChesapeake Bay as an ecosystem serves as a sink forpollutants released in many inland watersheds. Asseveral nuclear power plants are sited in Pennsylvaniaalong the Susquehanna River. the Bay area may bethe critical system upon which to base pollutant ratesfor each of these nuclear plants.
4. Detailed models should be developed whichcan be used in simulation experiments to predict theenvironmental effects of particular power planteffluents and effluent levels.
GEOLOGY
Power plants are extremely heavy structureswith very low settling tolerances. The underlyingbedrock must be extremely solid, and must not allowwater to pass through it easily.
The probability of the occurrence of anearthquake and its potential strength must be takeninto account in the selection of a power plant site.Current practice in the selection of sites for nuclearpower plants is based upon the knowledge ofearthquake potential plus a large safety factor.Nuclear plants are not located on or in the immediatevicinity of faults which are considered at all likelyto display any earthquake activity. An earthquakerisk map has been developed for the entire UnitedStates and should prove a valuable aid for thoseinvolved in plant siting decisions.
Large quantities of water are needed in today'spower plants for cooling. It is thus necessary for aplant site to he near a source of water suitable forits cooling needs. A detailed study of the surface andground water must accompany any site evaluation.Information on the cooling capacity of this water canthen be used to determine the number and locationof power plant sites along any major river lake, bayor over any major underground source
Cooling sowers, which transfer heat directly intothe atmosphere on the plant site. are considered inall new power plant installations. These towersproduce environmental eflect such as logging whichmust be assessed.
METEOROLOGY
It is necessary to establish that a site has weathereoEitlitions suitable for a power plant. Such adetermination require an evaluation of the airpollution potential of the site and many weather andclimate factors. concentrations must hepit.dicted fin- a range of weather conditions. Modelsbased on correlation of pollution concentrations
weathe, conditions must be used.
LAND REQUIREMENTS
I Lompari,:on land area requirements fordill.,ivut types of plants is given in Table 1 1. Theseesainpie are for power Ni,111011S of a 1000 megawatteahac it
Plant Fuel
Oit
Niiclear
Table 11
Land Area for Power Plants
Number of Acres Required
900-1200150-350100-200300-900
ono wagon Oita a coal-fired station requirts somuch space is that at least a 90 day suppl) of coalmust he Awed on tle site. along with the eventual%.astt. ashes. A modern plant will burn 8.000 toIit,fx)ft ?Adis o:....0:11 per day, so that a 1000 megawattstation normally requires a reserve yard of 20 to 30acres with the coal piled 40 feet high. There musthe a large area for waste storage, and the train yardfin the delivery of the coal also consumes much landarea.
Oil and gas fueled power plants are usuallysupplied by pipeline. and therefore require onlymucks, on-site fuel storage.
In a nuclear power plant. the area required forfuel storage is very small The only storage facilityneeded is a storage vault for new and used fuel. Therdativele large site area required for a nuclear plantN Ili:CON:fry for providing distance between thereactor and people. This distance is called an
esdusion distance and is required by law. It provides
55
a protective factor between the public and the reactorin the event of a reactor accident. At nuclear stations.this exclusive distance runs between 1200 and 4400feet. There must also he a low population zoneimmediately surrounding the exclusion area, and apopulation center distance representing the distancefrom the plant to the nearest boundary of a desnsclypopulated area.
ENVIRONMENTAL IMPACT EVALUATION orPLANT SITE SELECTION
All power plants will have some adverse effectsupon the environment. With the proper selection ofsites. appropriate design of facilities and carefulpre-construction and pist-construction studies. muchcan be done to reduce such effects. The followingfactors need to he considered in assessing
environmental imrct.
Air Quality Studies
1 Determine present population d' ributionand ..xpected growth !tat terns; determine existing andexpected industries in the area and likely emissionsto the air.
2 Consider factors of land surface affectingdispersion of air emissions; make measurement ofprevailing wind directions and velocities, temperatureranges. precipitation values and factors related totemperature inversions; provide for air monitoringbefore plant startup and after plantoperationmeasuring wind direction and velocity.temperature, sulfur dioxide content, nitrogen oxidecontent, particulate content, dust fall and haze.
Water Quality and Quantity Studies
1. Determine quantity availability foronce-through cooling water system; or for coolingtowers where water supplies are limited: determineavailable average and firm flows in streams to he usedto supply cooling water; determine available groundwater supplies.
2. Measure physical and chemical properties ofthe water.
3. Algal studies. large invertebrate animalstudies. fish population studies and an; unique or
significant ecosystems studies should determinespecies and quantities present at proposed points ofintake and discharge of cooling water supplies beforeand after plant startup to determine their seasonalvariations and the environmental effects of plantoperations.
4. Make temperature prediction studies todemonstrate the ability of cooling water systems tomeet surface or ground watci temperature standards.
Radioactive Waste Studies
1. Determine proposed releases based on siteconditions, including background radiation, weathercharacteristics and related factors; measurements andstudies necessary to predict the effects of projectconstruction and operation on the environment mustbe made.
2. Monitoring program.; must be set up; stationsshould be selected to measure radiation wheremaximum effects of the plant operation are expectedand also where background radiation can bedetermined. the following materials should besampled in the region of the site to determine thelevel of radioactivity airborne dust, precipitation.milk. external radiation, waters and sediments 'andwater organisms.
Land Use Studies1. Sufficient acreage must he made available,
and in the case of nuclea' plants must be accordingto AEC regulations. the relationship of nuclear plantsto population centers must be in accord with AECregulations
2. Study physical characteristics of the site.determine the incidence of flooding or wind storms.
3. Determine relationship to all historical.archeological ni cultural areas in the site region andeffects on these areas
4. The plant site should conform with adoptedslate and regional land use plans; full considerationshould he given to recreational and other computableuses of the plant site. visitor centers and otherfacilities to at.ommodate the visiting public shouldhe provided.
The architectural design should blend withthe surrounding area and he accompanied byappropriate latidScapig
56
GOVERNMENT STANDARDS ON PLANT SITING
All proposed power plants must meetgovernmental standards. Many of these standards arcset by the federal government, but state and regionalcontrol of site selection, air and water quality.transmission line routing and transportation methodsis increasing
Many more governmental standards must he metby nuclear plants than by fossil fueled plants. Theaverage nuclear power plant must get in excess of100 state and federal permits to become operational.(See Appendix IV)
Finding sites that meet all these requirementsis not an easy 'ask. As the Tennessee ValleyAuthority's manager of power, G. O. Wessenatier, hassaid. "An ideal site for a nuclear plant is one forwhich there is no evidence of any seismic activitymet the past millennia, is not subject to hurricanes,tornadoes or floods; is an endless expanse ofunpopulated desert with an abundant supply of verycold water flowing nowhere and containing noaquatic life. Most important, it should he locatedadjacent to a major population center. "
FUTURE SITING POSSISILITES FOR NUCLEARPLANTS
Offshore Siting
The use of offshore sites adjacent to coastalcities is under development. Figure 19 shows one ofthese proposed sites. These sites would alleviate theproblems of land availability, esthetic compatabilityand cooling water supply. In add.ti-m. these offshoresites could be located close to the major market areasof the east and west coasts.
Nuclear power plants such as the one in Figureit) ma) be Hilt on a massive steel and concretebarge. about 400 by 400 feet. A nuclear plant onthe barge would rise t 75 feet above sea level,protected on four sides by a breakwater enclosure.
The breakwater enclosures resting on the seabottom would have walls too feet thick and wouldrise 60 feet above the sea's surface. They would hedesigned to protect the plan, from all natural perilssuch as hurricane-whipped seas or from %tray ships.
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The possibility of siting plants under the sea isalso being investigated.
Underground Sites
Underground sites for nuclear power plants arebeing studied for location near urban centers. Theprimary reason for these studies is to determinesafety advantages and the possible utilization of wasteheat. Underground sites will not require valuablesurface areas near cities.
58
Chapter 8
ENERGY CONSERVATION: THE NEED FOR MORE EFFICIENT USE OF ENERGY
in the past history of the United States, energyhas always been a relatively cheap commodity.Because of its low price, little effort has been madeto use energy efficiently.
But as we have seen, low-cost energy is no longerabundant. The growing shortages of traditional fuelswill most likely result in a significant rise in the priceof these fuels, and in an increase in the price of theenergy derived from these fuels. The price ofelectricity rose in 1971. the first increase since 1946.Our national consumption of both natural gas andpetroleum are now in excess of our production,resulting in a greater dependance upon foreignsources for imports. Thus the more efficient use ofenergy is necessary. Fortunately, it is possible to saveon our energy expenditures.
The consumption of energy in the United Statesis estimated to be 63 x 1015 BTU per year. Of thisamount, the greatest single use is for transportation(25 per cent). Space heating requires 19 per cent ofour energy supply, while all industrial applicationsrequire about 36 per cent for such items as processsteam, electrical drive of various processes and directheating. The efficiencies of all these processes are lessthan 50 per cent, so that at least half of all the energyproduced is discarded as waste heat. If this loss couldbe reduced by only one per cent, this would representa savings in energy equivalent to 100 million barrelsof petroleum per year.
HOW TO ACHIEVE INCREASED CONSERVATIONOF ENERGY
The largest energy saving (and the easiest toaccomplish) would be in the heating and lighting ofhomes and commercial buildings. These structuresseldom have been designed to conserve energy. Theyusually have inadequate insulation, and allow excessleakage of outside air. Most commercial buildingshave large window areas, excess ventilation andinefficient heating and cooling equipment.
Guidelines in the form of building regulationswhich would set minimum standards for constructionbased upon the economically optimum amount ofinsulation for new buildings could save up to 42 per
59
cent of the heat energy required. These standardswould also reduce air conditioning energyrequirements.
Another step would he to design furnaces whichwould lose less heat in the exhaust. Modern furnacesare typically about 75 per cent efficient, but poormaintenance may reduce this from 35 to 50 per cent.Thus it pays to have a furnace serviced regularly.
Household appliances use a surprisingly largeamount of energy. If electric igniters now availableon the market were to replace pilot lights on gasappliances, the savings would he substantial. Fromsix to 10 per cent of all the natural gas consumedin this country each year is burned by appliance pilotlights. Frostfree refrigerators or freeters use almosttwice as much electricity as units which arc manuallydefrosted. .Fluorescent lamps use only one-fourth asmuch current as incandescent bulbs.
Industry consumes about 40 per cent of thetotal U.S. production of energy, but economicincentives will cause industry to increase itsefficiency. The most substantial of these incentivesin the near future will probably be rising fuel prices.
The utility industry has improved the efficiencyof electrical generation from five per cent in 1900to 40 per cent in the newest coal-fired plants. Theproposed development of combined cycle powerplants, which will use high temperature gas turbinesor magnetohydrodynamic generators with steamturbines, could increase plant effieciency to 50 or60 per cent.
Savings in transportation will he more difficultto achieve because more efficient modes of travelwould involve changes in our life-styles, especially ourcommitment to the automobile. Automobilesaccounted for 21 per cent of the total U.S. energyconsumption in 1972. The average American car getsabout 12 miles per gallon, which is about half themileage of most smaller European cars. Theinstallation of antipollution devices which have hecnrequired by law will further reduce the pasolinemileage. The growing U.S. dependance on foreign oilimports plus the price increases which theoil-exporting countries have already started to impose
will cause a sharp rise in the price of gasoline.Newsweek magazine, in its January 8, 1973 issue(p.9), predicts that by 1977 the price of gasoline willbe about $1.00 per gallon. This fuel price will giveeconomic impetus to less automobile travel and agreater demand for more efficient mass transitsystems.
SUGGESTIONS FOR GOVERNMENT INCENTIVESTO CONSERVE ENERGY
Several suggestions have been put forward which
would provide government incentives for theconservation of energy and the control of pollutants.These include:
1. A tax on pollutants. Under this proposal,industries would he surcharged by the governmentfor the amount of pollution they release. This taxwould increase the cost of the products theymanufacture. or would decrease their profits. Thiswould provide an economic incentive for industry toreduce its pollution as much as possible to escapepaying the surcharge.
2. Labelling legislation. Laws requiring thatlabels he put on consumer appliances stating theenergy consumption of these appliances have beensuggested. This would encourage the public topurchase brands with lower consumption, acting asan incentive to manufacturers to produce applianceswith energy consumption as low as possible.
3. Altering rate structures. Present rate
structures are such that those who use the
least amount of electricity pay the highest rate, whilethose who use larger amounts pay a lower rate.Reversal of this structure would cause those who uselarge amounts of electricity to conserve it wheneverpossible because of its high price.
60
SUMMARY
We must keep before us the fact that all energysources have some Impact upon the environment.Table 12 summarizes the effects discussed in thepreceding chapters. It also summarizes the suppliesof the fuels .
To quote S. David Freeman, former Director ofthe Energy Policy Staff of the President's Office ofScience and Technology, "After man's long strugglefor bare survival and simple comforts, the stage hasbeen reached where most people in this country aretrained and paid for thinking. An abundant supplyof low-cost energy is essential to continue this trend,freeing man from burdensome chores and enablinghim to spend more and more of his time enjoyingthe pleasures of affluence, leisure and education. Itis for these reasons that national policy has long beento assure an abundant supply of low cost energy."
To supply these needs, we must be prepared tomake several vital decisions in the near future:
I. How can we best produce electrical energyto meet increasing needs to maintain our quality oflife and still maintain a quality environment? Wewant both.
2. What energy source or combination of energysources will produce the least detrimental effectsupon the environment?
EnergySource
Table 12
These are decisions which the American publicmust make. They are extremely important decisionsand they will affect the lives of unborn generations.We must balance the availability and importance offuels, the impact on the environment and humanneeds. We must keep in mind that pollution is morea by-product of affluence than of poverty.
Whether the production of energy will comefrom fossil fuels, nuclear reactors or from a varietyof sources is a decision which must be made aftera careful weighing of the facts. In the words ofCongressmai Craig Hosmer of the Joint Committeeon Atomic Energy, "Society must balance risk againstpotent;a1 benefits to the people; the ultimate decisionshould be that which is the greatest good for thegreatest number!'
The decision is yours.
Environmental Effects of Electrical Power Generation
Effect onLand
Effects onWater
Effects onAir
Biological SupplyEffects
Coal Disturbed landLarge amountsof solid waste
Acid minedrainageIncreased watertemperature
Sulfur oxidesNitrogen ox-idesParticulates
Respiratoryproblems fromair pollutants
Largereserves
Oil Wastes in theform of brine
Oil spillsIncreased watertemperature
Nitrogen ox-idesCarbon mlnox-ideHydroca, dons
Respiratoryproblems fromair pollutants
Limiteddomesticreserves
Gas Increasedwater temp-erature
Some oxidesof nitrogen
Extremelylimited doorreserves
Uranium Disposal ofradioactivewaste
Increasedwater temperature
None detectablein normaloperation
Largereserves if. tare develop(
61
estic
reef
APPENDIX 1
GLOSSARY OF TERMS
The following terms are included to aid you in your understanding of the material included in the textand of the terms you will encounter as you investigate the effects of power generat.on. Many of the nuclearterms are exerpted from the U.S. Atomic Energy Commission booklet Nuclear Terms: A Brief Glossary. Manyother terms have been added by the committee in order to increase your understanding of the specific wordsrelating to power production.
absorbed dose
absorber
absorption
When ionizing radiation passes through matter, some of its energy is impartedto the matter. The amount absorbed per unit mass of irradiated material is calledthe absorbed dose, and is measured in rems and rads.
Any material that absorbs or diminishes the intensity of ionizing radiation.Neutron absorbers. like boron. hafnium and cadmium are used in control rodsfor reactors. Concrete and steel absorb gamma rays and neutrons in reactorshields. A thin sheet of paper or metal will absorb or attenuate alpha particlesand all except the most energetic beta particles.
The process by which the number of particles or photons entering a body ofmatter is reduced by interaction of the particles or radiation with the matter:similarly, the reduction of the energy of particles or photons while traversilla body of matter.
activation The process of making a material radioactive by bombardment with neutrons,protons, or other nuclear particles or photons.
acute radiationsickness syndrome
AEC
air sampling
alpha particle
atom
atomic bomb
An acute organic disorder that follows exposure to realtively severe doses ofionizing radiation. it is characterized by nausea. vomiting, diarrhea blood cellchanges, and in later stages by hemorrhage and loss of hair
The U.S. Atomic Energy Commission.
The collection and analysis of samples of air to measure its radioactivity orto detect the presence of radioactive substances, particulate matter or chemicalpollutants.
(Symbol° ) A positively , ;lamed particle emitted by certain radioactive materials.It is made up of two neutrons and two protons bound together. /fence it is
identical with the nucleus of a helium atom. It is the least penetrating of thethree common types of decay radiation.
A particle of matter whose nucleus is indivisible by chemical means. It is thefundamental building block of the chemical elements.
A bomb whose energy conies from the fission of !wavy elements such asuranium-235 and plutonium-239.
Atomic Energy (Abbreviation AFC) The independent civilian agency of the federal governmentCommission with statutory responsibility for atomic energy matters. Also the body of live
persons, appointed by the President, to direct the agency
atomic mass (See atomic weight. mass)
(11
atomic mass unit (Abbreviation amu) One-twelfth the mass of a neutral atom of the most abundantisotope of carbon. carbon-I 2.
atomic number (Symbol Z) The number of protons in the nucleus of an atom, and also itspositive charge. Each chemical has its characteristic atomic number, and thenumbers of the known elements form a complete series from I (hydrogen) to105.
atomic reactor A nuclear reactor.
atomic weight
autoradiograph
background
radiation
backscatter
The mass of an atom relative to other atoms. The present-day basis of the scaleof atomic weights is carbon; the most common isotope of this element hasarbitrarily been assigned an atomic weight of 12. The unit of the scale isone-twelfth the weight of the carbon-12 atom, or roughly the mass of one protonor one neutron. The atomic weight of any element is approximately equal tothe total number of protons and neutrons in its nucleus.
A photographic record of radiation from radioactive material in an object. madeby placing the object very close to a photographic film or emulsion. The processis called autoradiography. It is used, for instance, to locate radioactive atomsor tracers in metallic or biological samples.
The radiation in man's natural rmvironment, including cosmic rays and radiationfrom the naturally radioactive elements. both outside, and inside the bodies ofhumans and animals. It is also called natural radiation. The term may also meanradiation that is unrelated to a specific experiment.
When radiation of any kind strikes matter (gas, solid or liquid), some of it maybe reflected or scattered back in the general direction of the source. Anunderstanding or exact measurement of the amount of backscatter is importantwhen beta particles are being counted in an ionization chamber, in medicaltreatment with radiation, or in the use of industrial radioisotopic thicknessgauges.
barrier shield A wall or enclosure shielding the operator from an area where radioactive materialis being used or processed by remote control equipment.
beta particle (Symbolr ) An elementary particle emitted from a nucleus during radioactivedecay. with a single electrical charge and a mass equal to 1 /1 837 that of aproton. A negatively charge beta particle is identical to an electron. A positivelycharged beta particle is called a positron. Beta radiation may cause skin burns,and beta-emitters are harmful if they enter the body. Beta particles are easilystopped by a thin sheet of metal,
BeV Symbol for a billion (109 ) electron volts. ;See electron volt.)
binding energy The binding energy of a nucleus is the minimum energy required to dissociateit into its component neutrons and protons.
biological dose The radiation dose absorbed in biological material. Measured in reins.
63
biological half life The time required for a biological system, such as a human or animal, to eliminateby natural processes half the amount of a substance (such as a radioactivematerial) that has entered it.
biological shield A mass of absorbing material placed around a reactor or radioactive source toreduce the radiation to a level safe for humans.
body burden The amount of radioactive material present in the body of a human or an animal.
boiling water reactor A reactor in which water, used as both coolant and moderator, is allowed toboil in the core. The resulting, steam can be used directly to drive a turbine.
bone seeker
breeder reactor
BTU
A radioisotope that tends to accumulate in the bones when it is introducedinto the body. An example is strontium -90, which behaves chemically likecalcium.
A reactor that produces more fissionable fuel than it consumes. The newfissionable material is created by capture in fertile materials of neutrons fromfission. The process by which this occurs is known as breeding.
British Thermal Unit. The amount of heat required to change the temperatureof one pound of water one degree Fahrenheit.
by-product Any radioactive material (except source material for fissionable material)material obtained during tt. production or use ef source material or fissionable material.
It includes fission products and mail other radioisotopes produced in nuclearreactors.
calorie (largecalorie)
carbon oxides
The amount of heat required to change the temperature of one kilogram ofwater one degree Centigrade.
Compounds of carbon and oxygen produced when the carbon of fossil fuelscombines with oxygen during burning. The two most comnam such oxides arecarbon monoxide, a very poisonous gas, and carbon dioxide.
cask A heavily shielded container used to store and/or ship radioactive materials.
cathode rays
chain reaction
charged particle
A stream of electrons emitted by the cathode, or negative electrode, of agas-discharge tube or by a hot filament in a vacuum tube, such as a televisiontube.
A reaction that stimulates its own repetition. In a fission chain reaction, afissionable nucleus absorbs a neutron and fissions. releasing additional neutrons.These in turn can he absorbed by other fissionable nuclei, releasing still moreneutrons. A fission chain reaction is self-sustaining when the number of neutronsreleased in a given time equals or exceeds the number of neutions lost byabsorption i,1 nonfissioning material or by escape from the system.
An ion: an elementary particle that carries a positive or negative electrik. charge.
chromosome The determiner of heredity within a cell.
64
cladding The outer jacket of nuclear fuel elements. It prevents corrosion of the fuel bythe coolant and the release of fission products into the coolant. Aluminum orits alloys, stainless steel and zirconium alloys are common cladding materials.
closed-cycle A reactor design in which the primary heat of fission is transferred outside thereactor system reactor core to do useful work by means of a coolant circulating in a completely
closed system that includes a hear exchanger.
coal gasification A process of obtaining methane and other combustible gases from coal, usingthe heat of the gas to generate alectrictiy, then burning the gases to operatea steam cycle.
containment
containmentvessel
control rod
coolant
The provision of a gas-tight shell or other enclosure around a reactor to confinefission products that otherwise inight be released to the atmosphere in the eventof an accident.
A gas-tight shell or other enclosure around a reactor.
A rod, plate or tube containing a material such as hafnium, boron, etc. usedto control the power of a nuclear reactor. By absorbing neutrons, a controlrod prevents the neutrons from causing further fission.
A substance circulated through a nuclear reactor to remove or transfer heat.Common coolants are water, heavy water, air, carbon dioxide, liquid sodiumand sodium-potassium alloy.
cooling tower A tower designed to aid in the cooling of water that was used to condensethe steam after it left the turbines of a power plant.
core The central portion of a nuclear reactor containing the fuel elements and usuallythe moderator, but not the reflector.
counter A general designation applied to radiation detection instruments or survey metersthat detect and measure radiation.
critical mass The smallest mass of fissionable material that will support a self-sustaining chainreaction under stated conditions.
criticality The state of a nuclear reactor when it is just sustaining a chain reaction.
curie (Abbreviation Ci) The basic unit to describe the intensity of radioactivity ina sample of material. The curie is equal to 37 billion disintegrations per second,which is approximately the rate of decay of I gram of radium. A curie is alsoa quantity of any nuclide having 1 curie of radioactivity. Named by Marie 4ndPierre Curie, who discovered radium in 1898.
daughter
decay chain
A nuclide formed by the radioactive decay of another nuclide, which in thiscontext is called the parent. (See radioactive series.)
A radioactive series.
65
decay heat The heat produced by the decay of radioactive nuclides.
decay, radioactive
decontamination
detector
deuterium
deuteron
dose
dose equivalent
dose rate
dosimeter
doubling dose
ecology
The spontaneous transformation of one nuclide into a different nuclide or intoa different energy state of the same nuclide. The process results in a decrease,with time, of the number of the original radioactive atoms in a sample. It involvesthe emission from the nucleus of alpha particles, beta particles (or electrons),or gamma rays; or the nuclear capture or ejection of orbital electrons; or fission.Also called radioactive disintegration.
The removal of radioactive contaminents from surfaces or equipment, as bycleaning or washing with chemicals.
Material or device that is sensitive to radiation and can produce a response signalsuitable for measurement or analysis. A radiation detection instrument.
(Symbol 2H or D) An isotope of hydrogen whose nucleus contains one neutronand one proton and is therefore about twice as heavy as the nucleus of normalhydrogen, which is only a single proton. Deuterium is often referred to as heavyhydrogen; it occurs in nature as I atom to 6500 atoms of normal hydrogen.It is nonradioactive. (See heavy water.)
The nucleus of deuterium. It contains one proton and one neutron.
(See absorbed dose, biological dose, maximum permissible dose, threshold dose.)
A term used to express the amount of effective radiation when modifying factorshave been considered. The product of absorbed dose multiplied by a qualityfactor multiplied by a distribution factor. It is expressed numerically in rems.
The radiation dose delivered per unit time. Measured, for instance, in rems perhour.
A device that measures radiation dose, such as a film badge or ionization chamber.
Radiation dose which would eventually cause a doubling of gene mutations.
The science dealing with the relationship of all living things with each otherand with their environment.
ecosystem A complex of the community of living things and the environment forming afunctioning whole in nature.
efficiency That percentage of the total energy content of a power plant's fuel which isconverted into electricity. The remaining energy is lost to the environment asheat.
electron (Symbol el An elementary particle with a unit negative charge and a massI /183 7 that of the proton. Electrons surround the positively charged nucleusand determine the chemical properties of the atom. Positive ele,:trons. orpositrons. also exist for brief periods of time as the result of positron decay.
66
electron volt
element
enrichment
environment
exclusion area
excursion
fast breeder reactor
fast neutron
fast reactor
fertile material
film badge
fissile material
fission
(Abbreviation ev or eV) The amount of kinetic energy gained by an electronwhen it is accelerated through an electric potential of 1 volt. it is equivalentto 1.603 x 104 2 erg. it is a unit of energy, or work, not of voltage.
One of the 105 known chemical substances that cannot be divided into simplersubstances by chemical means. A substance whose atoms all have the same atomicnumber. Examples are hydrogen, lead, and uranium. Not to be confused withfuel element.
(See isotopic enrichment)
The total surroundings of an organism which act upon it.
An area immediately surrounding a nuclear reactor where human habitation isprohibited to assure safety in the event of an accident.
A sudden, very rapid rise in the power level of a reactor caused by supercriticality.Excursions are usually quickly suppressed by the negative temperature coefficientof the reactor and/or by automatic control rods.
A reactor that operates with fast neutrons and produces more fissionable materialthan it consumes.
A neutron with kinetic energy greater than approximately 1,000,000 electronvolts.
A reactor in which the fission chain reaction is sustained primarily by fastneutrons rather than by slow-moving neutrons. Fast reactors contain little orno moderator to slow down the neutrons from the speeds at which they areejected from fissioning nuclei.
A material, not itself fissionable by thermal neutrons, which can he convertedinto a fissionable material by irradiation in a reactor. There are two basic fertilematerials, uranium-238 and thorium-232. When these fertile materials captureneutrons, they are partially converted into fissionable plutonium-239 anduranium-233, respectively.
A light-tight package of photographic film worn like a badge by workers innuclear industry or research, used to measure exposure to ionizing radiation.The absorbed dose can be calculated by the degree of film darkening causedby the irradiation.
While sometimes used as a synonym for fissionable material, this term has alsoacquired a more restricted meaning; namely, any material fissionable by neutronsof all energies, including thermal (slow) neutrons as well as fast neutrons. Thethree primarily fissile materials arc uranium-233. uranium-235 andplutonium-239.
The splitting of a heavy nucleus into two approximately equal parts (which arenuclei of lighter elements). accompained by the release of a relativel!, largeamount of energy and generally one or more neutrons. Fission can occurspontaneously. but usually is caused by nuclear absorption of gamma rays.neutrons or other particles.
fission fragments The two or more nuclei which are formed by the fission of a nucleus. Alsoreferred to as primary fission products. They are of medium atomic weight.and are radioactive.
fission products The nuclei (fission fragments) formed by the fission of heavy elements, plusthe nuclides formed by the fission fragments' radioactive decay.
fissionable material
flux (neutron)
fly ash
Commonly used as a synonym for fissile material. The meaning of this termhas also been extended to include material that can be fissioned by fast neutronsonly, such as uranium-238. Used in reactor operations to mean fuel.
A measure of the intensity of neutron radiation. It is the number of neutronspassing through one square centimeter of a given target in one second. Expressedas n x v, where n = the number of neutrons per cubic centimeter and vtheir velocity in centimeters per second.
Small particles of ash produced by the burning of fuels. They are dispersedup the smoke stack and may be carried some distance before they settle tothe earth.
food chain The pathways by which any material (such as radioactive material from fallout)passes from the first absorbing organism through plants and animals to humans.
fossil fuel
fuel (nuclear)
fuel cycle
Naturally occurring substances derived from plants and animals which lived inages past. The bodies of these long-dead organisms have become our recoverablefuels which can be burned, such as lignite, coal, oil and gas.
Fissionable material used or usable to produce energy in a reactor. Also appliedto a mixture, such as natural uranium, in which only part of the atoms arereadily fissionable, if the mixture can be made to sustain a chain reaction.
The series of steps involved in supplying fuel for nuclear power reactors. It
includes mining, refining, the original fabrication of fuel elements, their use ina reactor, chemical processing to recover the fissionable material remaining inthe spent fuel, reenrichment of the fuel material, and refabrication into newfuel elements.
fuel element A rod, tube, plate or other mechanical shape or form into which nuclear Fuelis fabricated for use in a reactor. (Not to be confused with element.)
fuel reprocessing The processing of reactor fuel to recover the unused fissionable material.
fusion The formation of a heavier nucleus from two lighter ones (such as hydrogenisotopes), with the attendant release of energy.
gamma rays (Symbol Y) High energy. short wave length electromagnetic radiation orwinatingin the nucleus. Gamma radiation frequently accompanies alpha and beta emissionsand always accompanies fission. Gamma rays are very penetrating and are beststopped or shielded against by dense materials, such as lead or depleted uranium.Gamma rays are essentially similar to x-rays, but are usually mote vnim.ctic.
68
gas cook ' reactor A nuclear reactor in which a gas is the coolant.
gaseous diffusion(p! t)
Geiger-Mullercounter
genets effects ofradiation
genetically significantdose
graphite (reactorgrade)
half life
half life,biological
half life, effective
half-thickness
health physics
A method of isotopic separation based on the fact that gas atoms or moleculeswith different masses will diffuse through a porous harrier (or membrane) atdifferent rates. The method is used by the AEC to separate uranium-235 fromuranium-238: it requires large gaseous diffusion plants and enormous amountsof electric power.
A radiation detection and measuring instrument. It consists of a go-filledGeiger-Muller tube containing electrodes, between which there is an electricalvoltage but no current flowing. When ionizing radiation passes through the tube,a short, intense pulse of current passes from the negative electrode to the positiveelectrode and is measured or counted. The number of pulses per second measuresthe intensity of radiation. It was named for Hans Geiger and W. Muller whoinvented in in the 1920s. It is sometimes caned simply a Geiger counter, ora G-M counter.
Radiation effects that can he transferred from parent to offspring. Anyradiation-caused changes in the genetic material of sex cells.
A population-averaged dose 'which estimates the potential genetic effects ofradiation on future generations. It takes into consideration the number of peoplein various age groups. the average dose to the reproductive organs to whichpeople in these groups : exposed, and their expected number of future children.
A very pure form of carbon used as a moderator in nuclear reactors.
The time in which half the atoms of a particular radioactive substance disintegrateto another iluclear form. Measured half lives vary from millionths of a secondto billions of years. Also called physical half life. (See decay. radioactive)
(See biological '..(r life.)
The time required for a radionuclide contained in a biological system. such asa human or an animal, to reduce its activity by half as a combined result ofradioactive decay and biological elimination. (Compare biological half life andhalt' life.)
The thickness of any given absorber that will reduce the intensity of a beamof radiation to one-half its initial value.
The science concerned with recognition, evaluation and control of health liaZatliSfrom ionizing radiation.
(0)
heat exchanger Any device that transfers heat from one fluid (liquid or gas) to another or tothe environment.
heat sink Anything that absorbes heat; usually part of the environment, such as the air.a river or outer space.
heavy water (Symbol D 20) Water containing significantly more than the natural proportions
(one in 6500) of heavy hydrogen (deuterium) atoms to ordinary hydrogen atoms.Heavy water is used as a moderator in some reactors because it slows downneutrons effectively and also has a low cross section for absorption of neutrons.
heavy water moderatedreactor
hydrocarbons
hydroelectricity
induced radioactivity
intensity
ion
ionization
ionization chamber
ionization event
ionizing radiation
A reactor that uses heavy water as its moderator. Heavy water is an excellentmoderator and thus permits the use of inexpensive (unenriched) uranium as afuel.
Compounds composed of hydrogen and carbon. These occur in petroleum,natural gas and coal.
Electricity produced from the energy of falling water. Dammed water is usedto turn turbines located below the dam.
Radioactivity that is created when substances are bombarded with neutrons asfrom a nuclear explosion or in a reactor, or with charged particles and photonsproduced by accelerators.
The energy or the number of photons or particles of any radiation incidentupon a unit area or flowing through a unit of solid material per unit of time.In connection with radioactivity, the number of atoms disintegrating per unitof time.
An atom or molecule that has lost or gained one or more electrons. fly this
ionization it becomes electrically charged. Examples: an alpha particle. whichis a helium atom minus two electrons: a proton, which is hydrogen atom minusits electron.
The process of adding one or more electrons to, or removing one or moreelectrons from, atoms or molecules, thereby creating ions. High temperatures,electrical discharges, or nuclear radiations can cause ionization.
An instrument that detects and measures ionizing radiation by measuring the
electrical current that flows when radiation ionizes gas in a chamber. makingthe gas a conductor of the electricity.
An occurrence in which an ion or group of ions is produced: for example. by
passage of a charged particle through matter.
Any radiation capable of displacing electrons from atoms or moleeu....s. therebyproducing ions. Examples: alpha, beta, gamma radiation. short-wave ultravioletlight. Ionizing radiation may produce severe skin or tissue damage.
irradiation Exposure to radiation, as in a nuclear reactor.
isotope
isotope separlon
isotopic enrichment
kilowatt hour
kilo-
lethal dose
low population zone
magnetic bottle
magnetic mirror
mass
mass-energy equation
One of two or more atoms with the same atomic number (the same chemicalelement) but with different atomic weights. An equivalent statement is that thenuclei of isotopes have the same number of protons, but different numbers ofneutrons. Thus carbon-12, carbon-13 and carbon-14 are isotopes of the elementcarbon, the numbers denoting the approximate atomic weights. Isotopes usuallyhave very nearly the same chemical properties, but somewhat different physicalproperties.
The process of separating isotopes from one another, or changing their relativeabundances, as by gaseous diffusion or electromagnetic separation. Isotopeseparation is a step in the isotopic enrichment process.
A process by which the relative abundances of the isotopes of a given elementare altered, thus producing a form of the element which has been enriched inone particular isotope and depleted in its other isotopic forms.
One kilowatt of electricity expended for one hour.
A prefix that multiplies a basic unit by 1000.
A dose of ionising radiation sufficient to cause death. Median lethal dose (MLDor LD-50) is the dose required to kill within a specific period of time (usually30 days) half of the individn:Is in a large group of organisms similarly exposed.The LD-50/30 for man is about 400,000 to 450,000 mrem.
An area of low population density sometimes required around a nuclearinstallation. The number and density of residents is of concern in providing,with reasonable probability, that effective protection measures can he taken ifa serious accident should occur.
A magnetic field used to confine or contain a plasma in controlled fusion(thermonuclear) experiments.
A magnetic field used in controlled fusion experiments to reflect charged particlesback into the central region of a magnetic bottle.
The quantity of matter in a body. Often used as a synonym for weight, which,strictly speaking, is the force exerted on a body by the earth.
The statement developed by Albert Einstein, German-born American physicist,that the mass of a body is a measure of its energy content. as an extPusionof his 1(0)5 special theory of relativity. The statement was subsequently verifiedexperimentally by measurements of mass and energy in nuclear reactions. Theequation, usually given as E = mc2, shows that when the energy of a bodychanges by an amount h (no matter what form the energy takes), the mass.m, of the body will change by an amount equal to EN-. The facto! c-, thesquare of the speed of light in a vacuum, may he reit:tided as the conversionfactor (elating units of mass and energy. The equation pi edicted the possibilityof releasing enormous amounts of energy by the conversion of mass to eneigy.It is also called the Einstein equation.
7
matter
maximum credibleaccident
maximum permissibledose
mean life
median lethal dose
mega-
Mev
milli-
moderator
molecule
mutation
natural radiation ornatural radioactivity
natural uranium
neutron
The substance of which a physical object is composed. All materials in theuniverse have the same inner nature, that is, they arc composed of atoms,arranged in different (and often complex) ways; the specific atoms and thespecific arrangements identify the various materials.
The most serious reactor accident that can reasonably be imagined from anyadverse combination of equipment malfunction, operating errors and otherforeseeable causes. The term is used to analyze the safety characteristics of areactor. Reactors are designed to be safe even if a maximum credible accidentshould occur.
That dose of ionizing radiation established by competent authorities as an amountbelow which there is no reasonable expectation of risk to human health, andwhich at the same time is somewhat below the lowest level at which a definitehazard is believed to exist. (See radiation protection guide)
The average time during which an atom, an excited nucleus, a radionuclide ora particle exists in a particular form.
(See lethal dose.)
A prefix that multiplies a basic unit by 1,000,000.
One million (106) electron volts. Also written as MeV.
A prefix that multiplies a basic unit by 1/1000.
A material, such as ordinary water, heavy water, or graphite, used in a reactorto slow down high velocity neutrons, thus increasing the likelihood of furtherfission.
A group of atoms held together by chemical forces. The atoms in the moleculemay be identical, as in H2, S2, and SR, or different, as in H2O and CO2. Amolecule is the smallest unit of a compound which can exist by itself and retainall its chemical properties. (Compare atom, ion.)
A permanent transmissible change in the characteristics of an offspring fromthose of its parents.
Background radiation.
Uranium as found in nature. it contains 0.7 per cent of uranium-235, Q0.3 percent of uranium-238 and a tract: of uranium-234. It is also called normal uranium.
(Symbol n) An uncharged elementary particle with a mass slightly greater thanthat of the proton, and found in the nucleus of every atom heavier thanhydrogen -1. A free neutron is unstable and decays with a half life of about13 minutes into an electron, proton and neutrino. Neutrons sustain the fissionchain reaction in a nuclear reactor.
72
neutron capture The process in which an atomic nucleus absorbs of captures a neutron.
nitrogen oxides Compounds of nitrogen and oxygen which may he produced by the burningof fossil fuels. Very harmful to health, and may he important in the fotniationof smogs.
nuclear energy The energy liberated by a nuclear reaction (fission of fusion) or by radioactivedecay.
nuclear power plant
nuclear reaction
nuclear reactor
Any device, machine or assembly that converts nuclear energy into some formof useful power, such as mechanical or electrical power. In a nuclear electricpower plant, heat produced by a reactor is generally used to make steam todrive a turbine that in turn drives an electric generator.
A reaction involving a change in an atomic nucleus, such as fission, fusion,neutron capture, or radioactive decay, as distinct from a chemical reaction, whichis limited to changes in the electron structure surrounding the nucleus.
A 'device in which a fission chain reaction can he initiated, maintained andcontrolled. Its essential component is a core with fissionable fuel. It usuallyhas a moderator, a reflector, shielding, coolant and control mechanisms.Sometimes called an atomic furnace, it is the basic machine of nuclear energy.
nuclear super- Superheating the steam produced in a reactor by using additional heat fromheating a reactor. Two methods are commonly employed: recirculatingu.at,I ng tae steam through
the same core in which it is first produced (integral superheating) or passingthe steam through a second and separate reactor,
nucleon A constituent of an atomic nucleus, that is, a proton or a neutron.
nucleonics The science and technology of nuclear energy and its applications.
nucleus The small, positively charged core of an atom. It is only about I/10,000 thediameter of the atom, but contains nearly all the atom's mass. All nuclei containboth' protons and neutrons, except the nucleus ot ordinary hydrogen, wind'consists of a single proton.
nuclide A general t..rtn applicable to all atomic forms of the elemonts. The tamerroneously used as a synonym for isotope, which properly !las a moredefinition. Whereas isotopes are the various forms of a single element (hencearc a f:mily of nuclides) and all have the same altIfIliC number and numberof protons, nuclides comprise all the isotipic forms of all the elements. Nuclidesare distinguished by their atomic number, atomic in,p.s. Anti nergy <tate
parent A radionuclide that upon radioactive decay or disintegration fields a specificnuclide (the daughtetl, chile' directly or as a later meinhcr of a radioactivoseries.
particulates Small particles of solid material pioduced by Mullinr of hale:..
permissible dose (See maximum permissible dose.)
7 3
personnel monitoring Determination by either physical or biological measurement of the amount ofionizing radiation to which an individual has been exposed, such as by measuringthe darkening of a film badge or performing a radon breath analysis.
physical half life (See half life.)
Pig A heavy shielding container (usually lead) used to ship or store radioactivematerials.
pile Old term for nuclear reactor. This name was used because the first reactor wasbuilt by piling up graphite blocks and natural uranium.
Plowshare
plutonium
The Atomic Energy Commission program of research and development onpeaceful uses of nuclear explosives. The possible uses include large- scaleexcavation, such as for canals and harbors, crushing ore bodies and producingheavy transuranic isotopes. The term is based on a Biblical reference, Isaiah 2:4.
(Symbol Pu) A heavy, radioactive, man-made metallic element with atomicnumber 94. Its most important isotope is fissionable plutonium-239, producedby neutron irradiation of uranium-238. It is used for reactor fuel and in weapons.
pollution The addition of any undesirable agent to an ecosystem.
pool reactor
population density
positron
power reactor
A reactor in which the fuel elements are suspended in a pool of water thatserves as the reflector, moderator and coolant. Popularly called a swimming poolreactor, it is usually used for research and training.
The number of persons per unit area (usually per square mile) who inhabit anarea.
A subatomic particle with the mass of an electron but having a positive chargeof the same magnitude as the electron's negative charge.
A reactor designed to produce useful nuclear power, as distinguished fromreactors used primarily for research, for producing radiation or fissionablematerials or for reactor component testing.
pressure vessel A strong-walled container housing the core of most types of power reactors;it usually also contains moderator, reflector, thermal shield and control rods.
pressurized water A power reactor in which heat is transferred from the core to a heat exchangerreactor by water kept under high pressure to achieve high temperature without boiling
in the primary system. Steam is generated in a secondary circuit. Many reactorsproducing electric power are pressurized water reactors.
primary fission products Fission fragments.
protection Provisions to reduce exposure of persons to radiation. For example. pioteetivebarriers to reduce external radiation or measures to prevent inhalation ofradioactive materials.
74
quality factor
rad
The factor by which absorbed dose is to be multiplied to obtain a quantitythat expresses, on a common scale for all ionizing radiations, the irradiationincurred by exposed persons. It is used because some types of radiation suchas alpha particles are more biologically damaging than other types.
(Acronym for radiation absorbed dose) The basic unit of absorbed dose ofradiation. A dose of one rad means the absorption of 100 ergs of radiationenergy per gram of absorbing material.
radiation The emission and propagation of energy through matter or space by means ofelectromagnetic disturbances which display both wave-like and particle-likebehavior: in this context the particles arc known as photons. Also, the energyso propagated. The term has been exti ded to include streams of fast-movingparticles (alpha and beta particles, free n lawns.. cosmic radiation, etc.). Nuclearradiation is that emitted from atomic nuclei in various nuclear reactions, includingalpha, beta and gamma radiation and neutrons.
radiation area Any accessible area in which the level of rr.timion is such that a major portionof an individual's body could receive in any one hour a dose in excess of 5millirem. or in any five consecutive days a dose in excess of 150 :taker%
radiation burn Radiation damage to the skin.
radiation damage A general term for the harmful effects of radiation on matter.
radiation detection Devices that detect and record the characteristics of ionizing radiation.instruments
radiation monitoring Continuous or periodic determination of the amount of radiation present in agiven area.
radiation protection Legislation and regulations to protect the public and laboratory or industrialworkers against radiation. Also measures to reduce exposure to radiation.
radiation protection The officially determined radiation doses which should not he exceeded withoutguide careful consideration of the reasons for doing so. These arc equivalent to the
older term maximum permissible dose.
radiation shielding Reduction of radiation by interposing a shield of absorbing material betweenany radioactive source and a person, laboratory area or radiation-sensitive device.
radiation source
radiation standards
radiation sterilization
Usually a man-made scaled source of radioactivity used in teletherapy,radi,)graphy, as a power source for batteries, or in various types of industrialgauges. Machines such as accelerators and radioisotopic generators and naturalradionuclides may also be considered sources.
Exposure standards, permissible concentrations, rules for ::ale handling.regulations for transportation, regulations for industrial control of radiation andcontrol of radiation by legislative means. (See radiation protection, radiationprotection guide.)
Use of radiation to cause a plant or animal to become sterile. that is. iik'apabieof reproduction. Also the use of radiation to kill all toms of 11:..bacteria) in food, surgical sutures, etc.
75
radiation warning symbol An officially prescribed symbol (a magenta trefoil on yellow background) whichshould be displayed when a radiation hazard exists.
radioactive
radioactive contamination
radioactive dating
radioactive isotope
radioactive series
radioactive waste
radioactivity
radioccology
radioisotope
radioisotopic generator
radiology
radiomutation
radioresistance
radiosensitivity
Exhibiting radioactivity or pertaining to radioactivity.
Deposition of radioactive material in any place where it may harm persons, spoilexperiments or make products or equipment unsuitable or unsafe for somespecific use. The presence of unwanted radioactive material found on the wallsof vessels in used-fuel processing plants, or radicactive material that has leakedinto a reactor coolant. Often referred to only as contamination.
A technique for measuring the age of an object or sample of material bydetermining the ratios of various radioisotopes or products of radioactive decayit contains. For example, the ratio of carbon-14 to carbon-12 reveals theapproximate age of bones, pieces of wood, or other archaeological specimenthat contain carbon extracted from the air at the time of their origin.
A radioisotope.
A succession of nuclides, each of which transforms by radioactive disintegrationinto the next until a stable nuclide results. The first member is called the parent,the intermediate members are called daughters, and the final stable member iscalled the end product.
(See waste, radioactive.)
The spontaneous decay or disintegration of an unstable atomic nucleus, usuallyaccompanied by the emission of ionizing radiation. (Often shortened to activity.)
The body of knowledge and the study of the effects of radiation on species. of plants and animals in natural communities.
A radioactive isotope. An unstable isotope of an element that decays ordisintegrate. spontaneously, emitting radiation. More than 1300 natural andartificial radioisotopes have been identified.
A small power generator that converts the heat released during radioactive decaydirectly into electricity. These generators generally produce only a few wattsof electricity and use thermoelectric or thermionic converters. Some also functionas electrostatic converters to produce a small voltage. Sometimes called an atomicbattery.
The science which deals with the use of all forms of ionizing radiation in thediagnosis and treatment of disease.
A permanent. transmissible change in form. quality or other characteristic ofa cell or offspring from the characteristics of its parent, due to radiation exposure.(See genetic effects of radiation, mutation.)
A relative resistance of cells, tissues, organs, or organisms to the injuriou. anionof radiation. (Compare radiosensitivity.)
A relative susceptibility of cells. tissues. organs or organisms to the !minionsaction of radiation. (Compare radioresistance.)
radium
radon
reactor
recycling
reflector
regulating rod
relative biologicaleffectiveness (RBE)
rem
rep
reprocessing
roentgen
roentgen equivalent, man
roentgen rays
safety rod
(Symbol Ra) A radioactive metallic element with atomic number 88. As foundin nature, the most common isotope has an atomic weight of 226. It occursin minute quantities associated with uranium in pitchblende, carnotite and otherminerals.
(Symbol Rn) A radioactive element, one of the heaviest gases known. Its atomicnumber is 86, and its atomic weight is 222. It is a daughter of radium in theuranium radioactive series.
(See nuclear reactor.)
The reuse of fissionable material, after it has been recovered by chemicalprocessing from spent or depleted reactor fuel, reenriched and then refabricatedinto new fuel elements.
A layer of material immediately surrounding a reactor core which scatters backor reflects into the core many neutrons that would otherwise escape. Thereturned neutrons can then cause more fissions and improve the neutron economyof the reactor. Common reflector materials are graphite, beryllium and naturaluranium.
A reactor control rod used for making frequent fine adjustment in reactivity.
A. factor used to compare the biological effectiveness of different types ofionizing radiation. It is the inverse ratio of the amount of absorbed radiation,required to produce a given effect, to a standard or reference radiation requiredto produce the same effect.
(Acronym for roentgen equivalent man.) The unit of dose of any ionizingradiation which produces the same biological effect as a unit of absorbed doseor ordinary x-rays. The RBE dose (in rems) = RBE x absorbed dose (in rads).
(Acronym for roentgen equivalent physical) An obsolete unit of absorbed doseof any ionizing radiation, with a magnitude of 93 ergs per gram. It has beensuperseded by the rad.
Fuel reprocessing.
(Abbreviation r) A unit of exposure to ionizing radiation. It is that amountof gamma or x-rays required to produce ions carrying 1 electrostatic unit ofelectrical charge (either positive or negative) in I cubic centimeter of dry airunder standard conditions. Named after Wilhelm Roentgen, German scientist whodiscovered x-rays in 1985.
(See rem.)
X-rays.
A standby control rod used to shut down a nuclear reactor rapidly in emergencies.
7 7
scaler
scram
An electronic instrument for rapid counting of radiation-induced pulses fromGeiger counters or other radiation detectors. It permits rapid counting byreducing by a definite scaling factor the number of pulses entering the counter.
The sudden shutdown of a nuclear reactor, usually by rapid insertion of thesafety rods. Emergencies or deviations from normal reactor operation cause thereactor operator or automatic control equipment to scram the reactor.
shield (shielding) A body of material used to reduce the passage of radiation.
smog A mixture of smoke and fog. A fog snade heavier and usually darker by smokeand chemical fumes.
smoke Suspension of small particles in a gas.
solar energy
somatic effects ofradiation
The energy produced by the fusion reaction occurring on the sun, which reachesthe earth as radian~ energy. This energy may be converted into heat or electricityby physical devices.
Effects of radiation limited to the exposed individual, as distinguished fromgenetic effects, which also affect subsequent unexposed generations. Largeradiation doses can be fatal. Smaller does may make .cite individual noticeablyill, may merely produce temporary changes in blood-cell levels detectable onlyin the laboratory, or may produce no detectable effects whatever. Also calledphysiological effects of radiation. (Compare genetic effects of radiation.)
spent (depleted) fuel Nuclear reactor fuel that has been irradiated (used) to the extent that it canno longer effectively sustain a chain reaction.
spill The accidental release of radioactive material.
stable Incapable of spontaneous change. Not radioactive.
stable isotope An isotope that does not undergo radioactive decay.
subcritical assembly A reactor consisting of a mass of fissionable material and moderator which cannotsustain a chain reaction. Used primarily for educational purposes.
subcritical mass
supercritical reactor
superheating
survey meter
sulfur oxides
An amount of fissionable material insufficient in quantity or of impropergeometry to sustain a fission chain reaction.
A reactor in which the power level is increasing. If uncontrolled, a supercriticalreactor would undergo an excursion.
The heating if a vap, particularly steam, to a temperature much higher thanthe boiling point at the existing pressure. This is done in power plants to improveefficiency and to redu.:e condensation in the turbines.
Any portable radiation detection instrument especially adapted for surveying orinspecting an area to establish the existence and amount of radioactive materialpresent.
Compounds composed of sulfur an oxygen produce(' by the burning of sulfurand its compounds in coal, oil and gas. Ilarmful to the health of man. plantsand animals, and may cause damage to materials.
thermal breeder reactor A breeder reactor in which the fission chain reactor is sustained by thermalneutrons.
thermal pollution Raising the temperature of a body of water such as a lake or stream to anundesirable level by the addition of heat. This heat may change the ecologicalbalance of that body of water, making it impossible for some types of life tosurvive, or it may favor the survival of other organisms, such as algae.
thermal reactor A reactor in which the fission chain reaction is sustained primarily by thermalneutrons. Most current reactors are thermal reactors.
thermal shield
thermonuclear reaction
A layer or layers of high density material located within a reactor pressure vesselor between the vessel and the biological shield to reduce radiation heating inthe vessel and the biological shield.
A reaction in which very high temperatures allow the fusion of two light nucleito form the nucleus of a heavier atom, releasing a large amount of energy. Ina hydrogen bomb, the high temperature to initiate the thermonuclear reactionis produced by a preliminary fission reaction.
threshold dose The minimum dose of radiation that will produce a detectable biological effect.
tracer, isotopic
turbine
unstable isotope
uranium
An isotope of an element, a small amount of which may be incorporated intoa sample of material (the carrier) in order to follow (trace) the course of thatelement through a chemical, biological or physical process, and thus also followthe larger sample. The tracer may be radioactive, in which case observationsare made by measuring the radioactivity. If the tracer is stable, massspectrometers or neutrons activation analysis may be employed to determineisotopic composition. Tracers also are called labels or tags, and materials aresaid to be labeled or tagged when radioactive tracers are incorporated in them.
A rotary engine made with a series of curved vanes on a rotating spindle. Maybe actuated by a current of fluid such as water or steam.
A radioisotope.
(Symbol U) A radioactive clement with the atomic number 92, and as foundin natural ores, an average atomic weight of approximately 238. The two principalnatural isotopes are uranium-235 (0.7 per cent of natural uranium), which isfissionable, and uranium-238 (99.3 per cent of natural uranium), which is fertile.Natural uranium also includes a minute amount of uranium-234. Uranium isthe basic raw material of nuclear energy.
uranium enrichment (See isotopic enrichment.)
waste, radioactive Equipment and materials from nuclear operations which are radioactive and forwhich there is no further use. Wastes are generally classified as high-level (having
79
radioactivity concentrations of hundreds of thousands of curies per gallon orcubic foot), low-level (in the range of I microcurie per gallon or cubic foot),or intermediate-level (between these extremes.)
watt A unit of pow, equal to one joule per second.
whole body counter
x-ray
A device used to identify and measure the radiation in the body (body burden)of human beings and animals: it uses heavy shielding to keep out background
radiation and ultrasensitive scintillation detectors and electronic equipment.
A penetrating form of electromagnetic radiation emitted either when the innerorbital electrons of an excited atom return to their normal state (these arecharacteristic x-rays), or when a metal target is bombarded with high speedelectrons (these are bremsstrahlung). X-rays ore always nonnuclear in origin.
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Appendix II
BIBLIOGRAPHY
GOVERNMENTAL PUBLICATIONS
Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, Nuclear Safety Information Center, J.R. Buchanan, Assistant Director, will supply information on breeder reactors, or other aspects ofthe nuclear energy program.
International Atomic Energy Agency, Kartner Ring 11, P. 0. Box 590, A1011 Vienna, Austria, NuclearPower and the Environment, 85 pp.
Joint Committee on Atomic Energy Hearings on Environmental Effects of Producing Electric Power,Phase I. October 28-31 and November 4-7, 1969, p. 357.
The National Power Survey, A Report on the Federal Power Commission, October 1964.
U.S. Atomic Energy Commission, Doc. WASH-1082. Current Status and Future Technical and EconomicPotential of Light Water Reactors, U.S. Government Printing Office. Washington, D.C., March 1968.
U.S. Atomic Energy Commission, Licensing of Power Reactors, U.S. Government Printing Office, 1967.
U S. Atomic Energy Commission, WASH-740, Theoretical Possibilities and Consequences of MajorAccidents in Large Nuclear Power Plants, March 1957.
U.S. Department of Interior, Pacific Northwest Water Laboratory. Corvallis, Oregon, Industrial WasteGuide on Thermal Pollution, Federal Water Pollution Control Administration, September 1968.
U.S. Printing Office. Code of Federal Regulations, Title 10.
U.S. Printing Office. Considerations Affecting Steam Power Plant Site Selection Energy Policy Staff.Office of Science and Technology. 1968.
U.S. Government Printing Office, Environmental Effects of Prodtking Electric Power, hearings beforethe Joint Committee on Atomic Energy, Congress of the United States, 1969-1970. Probably themost complete and current collection of data on wastes from fossil fuel and nuclear power plants.Hearing reports published in three parts: Phre I, January 1970. Phase H and III. Spring 1970.
U.S. Government Printing Office. Nuclear Safety. i. -ued quarterly.
PERIODICALS
Commoner. Barry and Richard Daly. "What is the Harm of Nuclear Testing to Human Inheritance?.Scientist and Citizen, 6:Nos. 9-10, September, October 196 t
'Conference on Inc Pediatric Significance of Peacetime Radioactive Fallout." Pediatrics 41:No. 1, 1968.
Green. L. h . "1.nergy Nee* Versus Environmental Pollution A Reconciliation? " Science,156:1448-1450.
81
Hartley, H. et. al.. "Energy for the World's Technology, "New Scientist, November 13, 1969, pp. 1-24.
Hogerton, J. F., 'The Arrival of Nuclear Power, "Scientific Amerisaga. February 1968, pp. 21-31.
Lapp, Ralph E., " Gaining Safety in Nuclear Power," Current March 1971.
Mills, G. Alex et. al., "Fuels Management in an Environmental Age, " Environmental Science andTechnology, 5:No. 1, pp. 30-38, January 1971.
Minnesota Committee for Environmental Information, "Cooling It in Minnesota," Environment, March1969, pp. 21-25.
Moshe, J. L. and A. P. Frass, 'Fusion by Laser," Scientific American, 224:No. 6, June 1971, pp. 21-33.
Novick, Sheldon, "Toward a Nuclear Power Precipice ',' Environment, pp. 3240. March, 1973.
Post, Richard F., "Prospects for Fusior Power ", Physics Today, pp. 31-39, April, 1973.
Sagan, Leonard A., "Infant Mortaility Controversy: Sternglass and His Critics," Bulletin of the AtomicScientists, October 1969, pp. 26-32.
Starr, Chauncey, "Social Benefit vs. Technological Risk," Science, Vol. 165, September 1969, pp.1232-1238.
Stein, Jane, "Coal is Cheap, Hated, Abundant, Filthy, Needed, "Smithsonian, February, 1973, pp. 19-27.
Stcrnglass, E. J., " Infant Mortality and Nuclear Tests, " Bulletin of Atomic Scientists, April 1969, pp.18-20.
Tamplin, A., Y. Ricker and M. F. Longmate," A Criticism of the Sternglass Article on Fetal and InfantMortality," Bulletin of the Atomic Scientists, December 1969. See also M. Friedlander and J.Klarmann, " How Many Children?' , Environment, 11:No. *10, December 1969.
Tsiviglou, Ernest C., "Nuclear Power: The Social Conflict," Environmental Science and Technolo,Vo. 5, pp. 404-410, May 1971.
Weaver, Kenneth F., "The Search for Tomorrow's Power, " National Geographic, November 1972, pp.650-681.
Woodson. Riley T., "Cooling Towers," Scientific American, May 1971 Vol. 224:No. 5, pp. 70-78.
BOOKS AND BOOK LETS
Calder. R. Living With the Atom, University of Chicago Press, 1962.
Committee for Nuclear information, Setting the Balance, Risks and Benefits of Nuclear Energy, September1965.
Curt:s, R. and E. Hogan, Perils of the Peaceful Atom, Ballantine Books, 1970.
82
Foreman, Harry, Nuclear Power and the Public, University of Minnesota Press, 1970.
Glasstone, Samuel, Sourcebook on Atomic Energy, D. Van Nostrand Co., Inc., 3rd Edition, 1967
Gofman and Tamp lin, Poisoned Power, Radale Press.
Hogerton, John F., Notes on Nuclear Power, Atomic Industrial Forum, Inc., 2nd Edition, 1970.
International Commission on Radiological Protection Reports, Pergamon Press, 14 publications on variousaspects of the evaluation of risks from ionizing radiation and the setting of star dards.
National Academy of Sciences. The Biological Effects of Atomic Radiation Summary Reports,Washington. D.C.. National Research Council, 1960.
National Academy of Sciences. Resources and Man, National Research Council, Committee on Resourcesand Man, Division of Earth Sciences, W. H. Freeman and Co., San Francisco, 1969.
Novick. Sheldon, The Careless Atom, Houghto i Mifflin Co., Boston, 1969.
Pennsylvania Power and Light Company, Nuclear Power in Perspectivej. 1972.
Public Health Service, Radioactive Waste Discharges to the Environment fro_m Nuclear Power Facilities,.Rockville. Md., March 1970.
Remick, Forrest J., Nuclear Power: Threat or Promise, printed by the Pennsylvania Electric Association.
Resources for the Future. 1755 Massachusetts Ave. NM., Washington, D.C., Patterns of U.S. EnergyUse and How They Have Evolved, Anneal Report, 1968.
Schubert. Jack and Ralph Lapp, Radiation: What It Is and How It Affects You Viking Press, 1958.
Seaborg, Glen T., Fission and FusionDevelopments and Prospects. Speech given at Berkely. California,November 20. 1969. U.S. Atomic Energy Commission.
U.N. Publications Office, New York. United Nations Scientific Committee on the Effects of Atomic_Radiation, Official records of the General Assembly, 13th Session. SuppleAnt 17 (A/3838) 1958;17th Session. Supplement 16 (A/5216); 19th Session, Supplent 14 (A/581,4) 1964; 21st Session,Supplement 14 (A/6314) 1966.
Wright, James H.. Power and the Environment. Westinghouse Electric Corp., Pittsburgh, Pa.. 1970.
From Understanding the Atom Series, U.S. Atomic Energy Commission, Division of TechnicalInformation. Washington. D.C.. the following titles are pertinent:
a. Atomic Feelh. Atomic Power Safetyc. Atoms, Nature and Mand. Controlled Nuclear Fusionc. The Creative Scientist. His Training and His Rolef. Direct Conversion of Energyg. The First Reactorh. The Genetic Effects of Radiation
83
i. Microstructure of Matterj. Neutron Activation Analysisk. The Natural Radiation Environment1. Nuclear Clocksm. Nuclear Energy for Desaltingn. Nuclear Power and the Environmento. Nuclear Power and Merchant Shippingp. Nuclear Power Plantsq. Nuclear Projectsr. Nuclear Propulsion for Spaces. Nuclear Reactorst. Nuclear Terms, A Glossaryu. Our Atomic Worldv. Plowsharew. Plutoniumx. Power from Radioisotopesy. Radioactive Wastes
. z. Radioisotopes and Life Processesi. Reading Resources in Atomic energy
ii. SNAP: Nuclear Space Reactorsiii. Sources of Nuclear Fueliv. Synthetic Transuranium Elementsv. Whole Body Counters
vi. Your Body and Radiation
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APPENDIX Ill
A DECISION MAKING MODEL
The reader has been confronted with numerousissues regarding the conflict between enjoying thesupposed benefits of a technological society andreducing the quality . of our environment tointolerable levels. Decisions to resolve the conflictmust be made; they will be made. If knowledgeablepeople refuse to make these decisions, lessknowledgeable persons will. The attitude of "lettingGeorge do i!" is a gross shirking of responsibility.
But how does a person with a taste ofknowledge about the problem (such as that acquiredthrough this rninicourse) make such decisions? Howdoes he evaluate the availabe data? How does heknow when he has surveyed all the data? How doeshe test for logical inconsistencies within the reports?The problem of analyzing large sets of informationand formulating workable solutions to problemsperceived is one of the most mind-boggling anddifficult endeavors of the human mind; it is also oneof the most rewarding !
A model or guide to this decision-makingprocess is presented in Figure 20. This model ispresented in the form of an instructional flowchartand suggests things to do (rectangles) and includescrucial questions (diamonds) which help pinpointerrors in interpretation of the data and conclusions.The rectangles and diamonds are logicallyinterconnected by arrows which suggest which waylo proceed.
cn of the main points in the flowchartrequires a brief explanation. First, one enters theintellectual process with an awareness ofenvironmental problems of electrical generation andan interest in the identification of solutions to theseproblems.
Stage 1. Survey your knowivige of power sourcesand the environment to acquire factual informationand the understanding of the basic issues involved.Completion of the minicourse is useful here.
Stage 2. Identify questions you may have about theissues for further refinement and analysis.
Stage 3. Have others raised similar questions?Answering this question can provide access to
85
discussions of the issue which have already beencompleted and tends to reduce the phenomenon ofre-inventing the wheel. In addition, the knowledgethat you may be raising a relatively new questioncan be an enlightening and rewarding experience.
Note: Diamonds represent decision in the form ofquestions which lend themselves to Yes, No, or ?answers. The path one takes through the flowchartis determined by the answer to the question.
Stage 4. Have solutions been posed? If Stage 3 hasbeen answered in the affirmative, we now begin toinvestigate the merits of the solutions.
Stage 5. Are solutions based on solid evidence? IfStage 4 has been answered in the affirmative, we cannow ask if there is substantial and logical evidenceto support the solution under question.
Stages 6-9. A negative response in either Stage 3, 4or 5 directs the decision-maker into the key branchof the flowchart. Stage 6 directs the learner to surveyinformation related to the problem (or solution), orto examine specific issues which relate to the problemunder consideration. Caution must be used here toavoid the temptation of switching to a relatedproblem. Stick to the issue at hand! In Stage 7, listalternative solutions to the problem. That is,determine, without excessive evaluation at this point,if there are other possible solutions to the problem.In Stage 8, start the process of evaluating the mainand alternative solutions from Stage 7 by listingadvantages and disadvantages of each solution.
Now that you have examined the evidence andtabulated the pros and cons of the problem orsolution, evaluate each as to its practicability andfeasibility. Then rank solutions from best to poorest.(Stage 9) In ranking, one arranges the solutions fromthe best to the poorest.
After Stage 9, the flow is cycled back to Stage10.
Stage 10. Are there unsolved problems? Presumingaffirmative answers to Stao.es 3, 4 and 5, WO .,re nowat the point where we see if all important question::have been asked. While it is recognized that the
words, "important questions "obviously involve value(subjective) judgments. such value judgements intechnoligical applications are unavoidable.
A negative answer to Stage 10 recycles the flowhack to Stage 2, and a positive response sends oneto the exit of the decision-making program.
Two additional comments regarding thisdecision-making flowchart are in order. First, itrepresents a series of intellectual processes and youmust try to understand it.
Second. the flowchart is only a firstapproximation (only representative) of the complexmental process involved in human problem-solving.It is hoped that it will be mnst valuable whenconsidered in its present form which is neitherexceedingly simple nor excessively complicated.
86
r
( ENTER )SURVEY YOURKNOWLEDGE OF
POWER SOURCESAND ENVIRONMENT
IDENTIFYQUESTIONS(PROB-
LEMS) ABOUTPOLLUTION
Yes(or ?)HAVE
OTHERS RAISEDSIMILAR QUES-
TIONS
Yes HAVE
SOLUTIONSSEEN
POSED'
Yes Yes 10
N(or7) N (so) N(ot?)
8
SURVEY INFORM-ATION RELATED
TO THE PROBLEM( OR SOLUTION)
Vr ALTERNA-
TIVE SOLUTIONSTO PROBLEM
LIST ADVANTAGESAND DISADVANTAGES
OF EACH SOLU-TION
VRANK SOLUTIONS
FROM BEST TOPOOREST
Flowchart of Basic Decision-MakingModel for Resolution of Environmental Problems
FiGUR 20
87
111
VEXIT
APPENDIX IV
LICENSING OF NUCLEAR POWER PLANTS
The following is a brief outline of theprocedures which must be followed by a utility inorder to construct and operate a nuclear power plant.
Before formally filing an application forconstruction and operation of a nuclear reactor, thecompany must select a site for the planned facilityaccording to the criteria specified by the U.S. AtomicEnergy Commission. Then two specific permits musthe obtained by the utility company: a constructionpermit and an operating license.
A. Steps in Obtaining a Construction Permit.
I. The utility company must submit a formalapplication to the Direr. orate of Licensingof the U.S. Atomic Energy Commission.The application must contain detailedinformation concerning:
a. Design and location of the proposedplant.
b. Safeguards to be provided.
c. Comprehensive data on the proposedsite and its environment.
2. A review of the application is made by theAEC Directorate of Licensing. An Analysisof the application is prepared.
3. Copies of the application are madeavailable to the public and to the AECAdvisory Committee on ReactorSafeguards. This committee reviews theapplication and holds conferences with theapplicrnt and the Directorate of Licensingstaff.
4. A public hearing is held, usually near theproposed site, by an AEC-appointedAtomic Safety and Licensing Board.Testimony may he given by privatecitizens, state and local officials andcommunity groups.
88
S. The Atomic Safety and Licensing Boardreviews the testimony presented at thepublic hearing and the findings of theDirectorate of Licensing and AdvisoryCommittee on Reactor Safeguards and thedecision is made for or against granting aconstruction permit.
6. The decision of the Atomic Safety andLicensing Board is subject to review by thefivemember Atomic Energy Commission.
7. A construction permit is granted or denied,and public notice is given of the action.
8. If a construction permit is granted,construction of the plar.' may begin. underconstant inspection of the AEC Division ofCompliance.
9. As construction progresses, the companyapplies to the AEC for an operating license.
B. Steps in Obtaining an Operating License
I. As construction of the reactor proceeds,AEC inspections assure that therequirements of the construction permitare met.
2. When final design is completed, theapplicant submits a final safety analysisreport in support of an application for anoperating license. The safety analysis reportmust include:
a. Plans for operation.
b. Procedures for coping with emergencysituations.
c. Final details on reactor design such ascontainment, core design and wastehandling systems.
3. The Directorate of Licensing prepares adetailed evaluation of the informationsubmitted and presents this evaluation tothe Advisory Committee on ReactorSafeguards.
4, The Advisory Committee on ReactorSafeguards prepares an independentevaluation and reports its opinion to theCommission. This is made public.
5. The AEC may then.
a. Publish a 30-day public notice of theproposed issuance of a provisionaloperating license,
b. Schedule a public hearing on theapplication.
c. Normally a hearing will not be heldat this stage unless:
i. There is a difficult safetyproblem of public importance.
ii. Substantial public interestwarrants a hearing.
d. If a public hearing is held, the decisionof the licensing hoard is subject toCommission review.
6. Any operating license may be provisionalfor an initial period of operation, at theend of which time a review is made todetermine conditions for a full term licenseof not more than 40 years.
a. The license sets forth the particularconditions which are to be met inorder to assure protection of thehealth and safety of the public.
b. Reactor operators must be
individually licensed by theCommission.
7. MI licensed reactors are inspectedperiodically by members of the AEC
89
Division of Compliance to assure that theyare operated in accordance with the termsof their licenses.
8. An Environmental Report must be
submitted as part of the applications forboth the Construction Permit and theOperating License.
