Rad Training Filtrol
Radiation Worker Training
Site Remediation
Birmingham Steel
May 2000
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Course Outline
Talk About 1 - Radiation Fundamentals and Biological Effects
Talk About 2 - Personnel Exposure Limits
Talk About 3 - Personnel Survey
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Course Outline
Talk About 5 - Contamination and Decontamination
Talk About 6 - Posting and Labeling
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Caution
Contamination Area
Anti-C Anti-C
Radiation Fundamentals
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Sources of RadiationThere are two main sources of ionizing radiation:
Natural Background
Man Made Sources
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Natural Background RadiationSources : Average
Dose
Cosmic - from the sun and outer space 28 mrem/yr
Terrestrial - from the earth's crust 28 mrem/yr
Radon - from the soil, (decay of uranium) 200 mrem/yr
Internal - from sources in the body 39 mrem/yr
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Man-made Radiation SourcesSources : Average
Dose
Medical radiation 54 mrem/yr
Consumer products 10 mrem/yr
Industrial uses < 3 mrem/yr
Atmospheric testing of nuclear weapons < 1 mrem/yr
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Average Annual ExposureThe total from all sources, natural and man made is
approximately 360 mrem/yr.
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p+
proton neutron
electron
nucleus
e
n0
The Atom
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Charge of the AtomThe number of electrons and protons determines the
overall electrical charge of the atom.
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ne e
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Ion+1 Charge
NeutralIon
-1 Charge
Ion = Atom with a positive or negative charge
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- -
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IonizationIonization is the process of removing electrons from a
neutral atom.ejected electron (negative ion)
incomingionizing
radiation
remaining atom (positive ion)
The positively charged atom and the negatively charged electron are called an ion pair.
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Ionizing RadiationIonizing radiation is radiation which carries enough
energy to cause ionization in the atoms with which it interacts.
n
(Alpha Particle)
(Beta Particle)
(Gamma Ray)
(Neutron Particle)
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Non-Ionizing Radiation
Radiation that doesn't have the amount of energy needed to
ionize an atom with which it interacts, is called "non-ionizing radiation".
Examples of non-ionizing radiation are radar waves, microwaves and visible light.
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RadioactivityRadioactivity is unstable (or radioactive) atoms trying to
become stable by emitting radiation.
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Radioactive MaterialRadioactive material is any material containing unstable
radioactive atoms that emit radiation.
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Radioactive ContaminationRadioactive contamination is radioactive material in an
unwanted place.
Radiation is a type of energy and contamination is a material.
It is important to note that exposure to radiation does not result in contamination of the worker.
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Radioactive DecayRadioactive decay is the process of radioactive atoms
releasing radiation over a period of time becoming stable (non-radioactive). (Also known as dis-integration.)
Large Unstable Nucleus
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Half LifeRadioactive half-life is the time it takes for one half of the radioactive
atoms present in a radioactive sample to decay.
After seven half-lives the activity of a radioactive sample will be less than 1% of the original activity.
Radioactive half - life of U-239 is 23.5 minutes.
Radioactive half - life of U-238 is 4,510,000,000 years.
0102030405060708090
100
1 2 3 4 5 6 7 8
% of atoms
that are
radioactive
# of half lives
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Four Types of Ionizing Radiation
p
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Alpha Particles
Beta Particles
Gamma Rays
Neutron Particlese-
n
The four basic types of ionizing radiation of concern in the nuclear industry are:
+2+
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Alpha Particlesp
p
n
n
+2
Characteristics:
Very massive, composed of two protons, two neutrons and no electrons. (Positive charge of plus two)
Penetrating Power - Very low. Average range in air is about one to two inches.
Shielding - Alpha particles are stopped by a sheet of paper, or the dead layer (outer layer) of skin.
Biological hazard - Alpha particles are considered an internal radiation hazard.
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Beta Particlese-
Characteristics:
Very small, negatively charged particle.
Penetrating Power - Low. Range in air of several feet and a range of a few millimeters in tissue.
Shielding - Most beta particles are stopped by plastic, glass, metal foil, or safety glasses.
Biological hazard - Internal, skin and eye.
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Gamma Rays
Characteristics :
Gamma () radiation has no charge and no mass. Consists of electromagnetic waves or photons.
Penetrating Power - High . Very long range.
Shielding - Shielded by very dense materials, such as lead, concrete or steel.
Biological hazard - External or whole body.
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rem (Roentgen Equivalent Man)
Unit for measuring dose equivalence.
Most commonly used unit.
Pertains to man - refers to the amount of biological damage produced by radiation.
Takes into account the energy absorbed (dose) and the biological effect on the body due to the different types of radiation.
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Conversion of rem and millirem
1 rem = 1000 millirem (mrem)
0.1 rem = millirem?
5000 millirem = _______ rem?
rem x 1000 = mremmillirem 1000 = rem .
.
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Dose Rate
Dose is the amount of radiation you receive.
Dose Rate is the rate at which you receive the dose
Dose rate = dose/time
mrem/hr, rad/hr, R/hr
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Contamination/Radioactivity
Disintegrations per minute (dpm) - describes the number of atoms disintegrating each minute in a radioactive source.
Radioactivity is measured in the number of disintegrations radioactive material undergoes in a certain period of time.
– One Curie = 2,200,000 000,000 (2.2 x 1012) dpm
– One microCurie = 2.22 x 106 dpm
– One picoCurie = 2.22 dpm
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Effects of Radiation on CellsRadiation causes damage to cells is by ionizing the
atoms in the cells.
Ionizing radiation may cause damage directly to the nucleus or any other part of the cell.
The interaction may cause physical damage, chemical damage, or both to occur to the cell.
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Cell SensitivityRadiation damage to cells depends on how sensitive the
cells are to radiation.
Cells that are actively dividing are more sensitive to environmental factors such as ionizing radiation.
– Examples: blood forming cells, intestinal lining, hair follicles, embryo/fetus.
Cells which divide at a less rapid pace or are more specialized are not as sensitive to damage by ionizing
radiation.
– Examples: brain cells or muscle cells
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Possible Effects of Radiation on Cells
Cells are not damaged
Cells repair the damage and operate normally
Cells are damaged and operate abnormally
Cells die as a result of the damage
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Acute and Chronic Radiation DosePotential biological effects of radiation depend on several
factors.
How much and how fast a radiation dose is received are
two of them.
Radiation doses can be grouped into two categories:
Acute dose
Chronic dose.
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Acute DosesAcute doses are large doses of radiation received in a short
period of time.
The body can't repair or replace cells fast enough from an acute dose and physical effects such as reduced blood count and hair loss may occur.
Death can occur if the exposure is high enough.
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Chronic Radiation Dose
Chronic radiation dose is typically a small amount of radiation received over a long period of time.
Typical examples of a chronic dose are:
The dose we receive from natural background.
The dose we receive from occupational exposure.
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Chronic vs. Acute DosesThe body is better equipped to tolerate a chronic dose than
an acute dose.
With chronic doses the body has time to repair damage.
With chronic doses the body also has time to replace dead cells.
Even sophisticated analysis of the blood does not reveal any biological effects from chronic doses.
Acute doses may overwhelm the cells repair mechanisms.
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Somatic Effects
Somatic effects are effects that occur in the exposed individual.
An example of a somatic effect is cancer.
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Factors Affecting Biological DamageTotal dose
Dose rate (how fast)
Type of radiation
Area of the body exposed
Cell sensitivity
Individual sensitivity
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Prenatal Radiation Exposure
Embryo/fetal cells are rapidly dividing which makes them sensitive to any environmental factors such as ionizing radiation.
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Potential Prenatal Hazards Some children who were exposed while in the
womb to the radiation from the atomic bomb were born with low birth weights and mental retardation.
It has been suggested, but not proven, that exposures to the unborn may also increase the chance of childhood cancer.
Only when doses exceed 15,000 mrem has there been significant increase in risk.
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Hazards from Uranium, Thorium
and Decay Products• Radiation Exposure
– Lung
– Long-term retention in lung
– Bone
– Uptake through lung or ingestion
– Deposit on surfaces of bone
– Whole body gamma exposure
• Chemical Toxicity– Heavy metal, similar to lead
– Kidney
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THORIUM-232
1.4E+10 y5.75 y 6.13 hr
RADIUM-228 ACTINIUM-228 * THORIUM-228
1.91 y
RADIUM-224 *
3.62 d
RADON-220
55.6 s
POLONIUM-216
0.15 s10.6 hr 60.5 m
LEAD-212 * BISMUTH-212 POLONIUM-212
60.5 m3.1 m
3E-7 s
THALLIUM-208 *
Thorium decay chain.
LEAD-208 (STABLE)
SHORT HALF-LIFE THORON DECAY
PRODUCTS
NOTE: Vertical Direction Represents Alpha Decay, Horizontal Direction Indicates Beta Decay. Times Shown are Half-Lives. Only the Primary Decay Mode is Shown. * Also Gamma Emitters, the Gamma Emissions from the Other Isotopes are Insignificant
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Estimated Days Lost Due to Daily ActivitiesAvg. Days
HEALTH RISK Lost
Unmarried male 3500Cigarette smoking 2250Unmarried female 1600Coal miner 110025% overweight 777Alcohol (U.S. average) 365Construction worker 227Driving a motor vehicle 207100 mrem/yr for 70 yrs 10Coffee 6
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Estimated Loss of Life Expectancy From
Industrial Hazards Avg. DaysIndustry Lost
Mining/Quarrying 328Construction 302Agriculture 277Radiation dose of 5 rem/yr. for 50 yrs. 250Transportation/Utilities 164All industry 74Government 55Service 47Manufacturing 43Trade 30Radiation accidents (deaths from exposure) <1
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Caution
Contamination Area
Anti-C Anti-C
Regulatory Basis
Personnel Exposure Limits
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Basis of NRC and State LimitsEnvironmental Protection Agency
National Council on Radiation Protection and Measurements (NCRP)
International Commission on Radiological Protection (ICRP)
ALARA - As Low As Reasonably Achievable
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Dose Limits
Whole Body 5 rem/yr.
Extremities 50 rem/yr.
Skin & organs 50 rem/yr.
Lens of the eye 15 rem/yr
Pregnant Woman 0.5 rem/term
Visitors and 0.1 rem/yr. Public
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Caution
Contamination Area
Anti-C Anti-C
Site Remediation
Personnel Survey
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PERSONNEL SURVEY
Detection/measurement of radiations emitted by radioactive materials to ensure:
Personnel are not inadvertently contaminatedContamination is not spreadRemember hands, face, & feet
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OPERATIONAL USE
Routine operationBattery check Background check
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MODEL 3 SURVEY METER AND MODEL 44-9 G-M DETECTOR
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POCKET DOSIMETER
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Caution
Contamination Area
Anti-C Anti-C
Site Remediation
Contamination and Decontamination
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Types of ContaminationRemovable contamination - contamination that can
readily be removed from surfaces and could be inhaled or ingested.
Fixed contamination - contamination that cannot be readily removed from surfaces.
Airborne contamination - contamination suspended in air. (breathable air zone)
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Sources of ContaminationPoor housekeeping in contaminated areas.
Sloppy work practices, such as cross-contamination of tools, equipment or workers
Leaks or tears in radiological containers; such as barrels, plastic bags or boxes.
Excessive motion or movement in areas of higher contamination.
Airborne contamination depositing on surfaces
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Indicators of PossibleArea Contamination
Leaks, spills, standing water
Dusty, hazy air
Damaged containers
Unexplained personnel contaminations at restricted area exits
Higher than normal background on personnel survey instruments
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Methods to Prevent Contamination
Preventative Maintenance
Establish adequate work controls before starting jobs.
Good housekeeping and cleaning up after jobs
Prompt corrective action for leaks and defective equipment
Administrative Controls (RWP’s, procedure reviews, access controls, etc.)
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Contamination Monitoring EquipmentContamination monitoring equipment is used to detect
radioactive contamination on personnel.
Hand Held Friskers
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Personnel Protective MeasuresWhen engineering methods are not adequate then
personnel protective measure will be used such as:
Protective clothing
Respiratory equipment
Anti-C
Anti-C
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Protective Clothing
The degree of clothing required is dependent on :
Contamination levels in the area
Type and form of contamination
The work being performed
Potential for increased levels of contamination
Area of the body at risk
Competing hazards, ie., heat stress, asbestos, etc.
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Proper Use of Protective Clothing Inspect all protective clothing prior to use.
Minimize the wearing of watches, rings, jewelry, etc.
Supplemental dosimeters should be worn outside the coveralls for ease of reading.
Don protective clothing prior to entering the contaminated area, then proceed directly to the work area.
Avoid getting coveralls wet.
Contact Radiation Protection personnel if clothing becomes ripped, torn or damaged.
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DecontaminationDecontamination is the removal of radioactive materials from locations
where they are not wanted. If the presence of transferable contamination is found, decontamination is a valuable means of control.
This is not always possible due to:
Economical conditions
Radiological conditions
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Decontamination
Decontamination is the removal of radioactive materials from locations where they are not wanted. This does not result in the disappearance of radioactive material but involves the transfer of the radioactive materials to another location.
» Material Decontamination
» Personnel Decontamination
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Personnel Decontamination
Radiation Protection personnel must be notified immediately in the event of personnel contamination.
Personnel decontamination will be done under the direction of Radiation Protection personnel.
The normal decontamination technique for skin is washing with mild soap and luke warm water.
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Caution
Contamination Area
Anti-C Anti-C
Site Remediation
Posting and Labeling
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Areas are designated with a magenta (or black) standard three-bladed radiological warning symbol on a yellow background.
Yellow and magenta ropes, tapes, chains, or other barriers are used to denote the boundaries.
Barriers are clearly visible from every side.
Entrance points have signs stating the entry requirements
Radiological Posting Requirements
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Radiation AreaAn area where radiation dose rates are > 5 mrem/hr but
< 100 mrem/hr.
The postings/signs will indicate:
"CAUTION, RADIATION AREA"
"TLD Required for Entry" Caution
Radiation AreaTLD
Required for Entry
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Contamination AreaAn area where contamination levels are higher the
removable contamination limits.The posting/signs will indicate:
"CONTAMINATION AREA"Caution
Contamination Area
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Radioactive Materials AreaAn area that is established to indicate areas where
radioactive materials are used, handled or stored.
The postings/signs will indicate the following:
"CAUTION, RADIOACTIVE MATERIALS AREA"
Caution
Radioactive Materials Area
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§20.1904 Labeling containers.(a) The licensee shall ensure that each container of licensed material bears a durable, clearly visible label bearing the radiation symbol and the words "CAUTION, RADIOACTIVE MATERIAL" or "DANGER, RADIOACTIVE MATERIAL." The label must also provide sufficient information (such as the radionuclide(s) present, an estimate of the quantity of radioactivity, the date for which the activity is estimated, radiation levels, kinds of materials, and mass enrichment) to permit individuals handling or using the containers, or working in the vicinity of the containers, to take precautions to avoid or minimize exposures.
(b) Each licensee shall, prior to removal or disposal of empty uncontaminated containers to unrestricted areas, remove or deface the radioactive material label or otherwise clearly indicate that the container no longer contains radioactive materials.
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Questions?? Questions??