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Nuclear Engineering & Radiation Health Physics Oregon State University
NE 319Societal Aspects of Nuclear
Technology
How Safe is Safe Enough?Dr. Jose N. Reyes, Jr.
Department of Nuclear EngineeringOregon State University
Spring Term 2001
Nuclear Engineering & Radiation Health Physics Oregon State University
Outline
• Risks - Everywhere You Look!• A Survey of Risks• A Definition of Safety• A Definition of Risk• Estimating Risk• Attitudes Towards Risk• The Move Towards “Risk-Based” Regulation• PRA for Nuclear Power Plants• An Exercise in Funding Safety Research
Nuclear Engineering & Radiation Health Physics Oregon State University
Washington man survives attack by deadly bacteria A 41-year-old recovers from flesh-eating and toxic-shock streptococcal infections.
Sunday, January 30, 2000
From The Associated Press
_____________________________________________________________
Risk of being infected with flesh-eating bacteria: 1 in170,000Risk of dying once infected: 1 in 4
Nuclear Engineering & Radiation Health Physics Oregon State University
Lightning Risks
• Risk of being struck by Lightning in any given year: 1 in 750,000
• The chances of surviving: 3 in 4
Nuclear Engineering & Radiation Health Physics Oregon State University
An Electrifying Personality
• According to the Guinness Book of World Records, Former Park Ranger Roy "Dooms" Sullivan Sullivan has the dubious distinction of being the most lightning-struck person ever recorded.
• Between 1942 and his death in 1983, Roy Sullivan was struck by lightning seven times.
Nuclear Engineering & Radiation Health Physics Oregon State University
An Electrifying Personality1. The first lightning strike shot through
Sullivan's leg and knocked his big toenail off.
2. In 1969, a second strike burned off his eyebrows and knocked him unconscious.
3. Another strike just a year later, left his shoulder seared.
4. In 1972 his hair was set on fire and Roy had to dump a bucket of water over his head to cool off.
Nuclear Engineering & Radiation Health Physics Oregon State University
An Electrifying Personality
5. In 1973, another bolt ripped through his hat and hit him on the head, set his hair on fire again, threw him out of his truck and knocked his left shoe off.
6. A sixth strike in 1976 left him with an injured ankle.
7. The last lightning bolt to hit Roy Sullivan sent him to the hospital with chest and stomach burns in 1977.
Nuclear Engineering & Radiation Health Physics Oregon State University
Survey
• Rank the activities according to your perception of the risk involved in participating!
• For Example:SPORTS ACTIVITIES Very Risky Somewhat Risky Little or No
Risk
Archery
Nuclear Engineering & Radiation Health Physics Oregon State University
Occupational Fatalities per 100,000 Employed
Occupation Number of Fatalities - 1993Executive/Managerial 3
Technicians 5
Sales 4
Administrative/Clerical 1
Farming 20
Forestry/Logging 142
Mechanics 6
Construction Supervisor 12
Construction Laborer 34
Truck Drivers 25
Taxi Drivers/Chauffeurs 50
Resident Military 10
Quarry Worker 28
Coal Miner 38
Metal Miner 22
Nuclear Engineering & Radiation Health Physics Oregon State University
Sports Injuries
SPORTSACTIVITIES
PARTICIPANTS(Millions)
INJURIES(Thousands)
INJURY PERPARTICIPANT
Archery 5.8 4.94 1 in 1170
Baseball 34.6 437 1 in 80
Basketball 29.6 761 1 in 40
Bicycle Riding 63.0 604 1 in 105
Billiards, pool 29.4 5.19 1 in 5660
Bowling 41.3 23.8 1 in 1730
Boxing 0.70 7.54 1 in 90
Fishing 51.2 76.0 1 in 670
Football 14.7 409 1 in 40
Golf 22.6 38.0 1 in 600
Ice Hockey 1.7 61.3 1 in 30
Ice Skating 6.9 36.4 1 in 190
Racquetball 5.4 15.4 1 in 350
Skateboarding 5.6 27.7 1 in 200
Soccer 10.3 146 1 in 70
Swimming 61.4 146 1 in 420
Waterskiing 8.1 15.3 1 in 530
Nuclear Engineering & Radiation Health Physics Oregon State University
Deaths Due to Injuries in 1992
Accident Type Deaths per Million PopulationMotor-vehicle 161Falls from stairs, ladders, etc 50Poisoning by drugs and medications 23Fires 16Drowning 14Medical care mistakes 10Inhalation and ingestion of food 4.7Air and space transport 4.3Water transport 3.3Railway 2.5Alcohol poisoning 1.3
Nuclear Engineering & Radiation Health Physics Oregon State University
How Do You Define Safety?
• “Safety” is the relative absence of the risk of realizing a set of undesirable consequences.
Nuclear Engineering & Radiation Health Physics Oregon State University
Definition of Risk• Risk: The likelihood of experiencing a defined set of
undesired consequences.– Involves both “likelihood” and “consequences” of an event.
• Likelihood: Slightly different then probability. Implies that some subjective judgement is used as a basis for determining the probability of an event. Typically assumes:– Magnitude of consequences will remain relatively constant
(e.g. fatalities /yr) with time.– All members of the population are equally exposed or
susceptible to risk.
Nuclear Engineering & Radiation Health Physics Oregon State University
Estimating Societal Risk
SOCIETAL RISK = FREQUENCY x MAGNITUDE
• Risk (Consequences/time)• Frequency (Events/time)• Magnitude (Consequence/Event)• e.g.:
50,000 Deaths/yr = (15 x 106 Accidents/yr) x ( 1 Death/300 accidents)
Nuclear Engineering & Radiation Health Physics Oregon State University
Estimating Individual Risk
INDIVIDUAL RISK = SOCIETAL RISK/(POPULATION AT RISK)
e.g.: If 200 million people in US:
(50,000 Deaths/yr)/(200 x 106 people) = 2.5 x 10-4 Deaths/(person-yr) Societal Risk / Pop. At Risk = Individual Risk
or 25 Deaths/100,000 people
Nuclear Engineering & Radiation Health Physics Oregon State University
Estimating Cost Risk
• Cost Risks for Injuries and Property Damage are expressed in terms $Dollar values associated with injuries and/or property damage.
Cost Risk = (Total $ Value)/ (Population at Risk)
Nuclear Engineering & Radiation Health Physics Oregon State University
Attitudes Towards Risk
• Types of activities with a fatality risk greater than 1 x 10-3 deaths/(person-yr) to the general public are generally unacceptable.– cars ~ 3 x 10-4 deaths/(person-yr)– falls ~1 x 10-4 deaths/(person-yr)– fires ~4 x 10-5 deaths/(person-yr)– drowning ~4 x 10-5 deaths/(person-yr)– firearms ~1 x 10-5 deaths/(person-yr)– poisoning ~1 x 10-5 deaths/(person-yr)– lightning ~8 x 10-7 deaths/(person-yr)
Nuclear Engineering & Radiation Health Physics Oregon State University
Attitudes Towards Risk
• High Risk Activities are usually on the order of the Disease Mortality Rate :
10-2 deaths/(person-yr)
• Low Risk Activities are usually on the order of the Natural Hazards Mortality Rate:
10-6 deaths/(person-yr)
Nuclear Engineering & Radiation Health Physics Oregon State University
Attitudes Towards Risk
• If some sports have a high likelihood of injury, (e.g., greater than 1 x 10-3 deaths/(person-yr), why do people participate in them?
• If the risk of dying in an airplane crash is less than dying in a car accident why would some people rather drive than fly?
Nuclear Engineering & Radiation Health Physics Oregon State University
Attitudes Towards Risk
• Acceptability Towards Risk depends on:– Benefits of Activity– Voluntary Nature of Activity– Perception– Consequence Distribution
Nuclear Engineering & Radiation Health Physics Oregon State University
Attitudes Towards Risk
• Consequence Distribution: – Given two activities with equal risk, the
public will tend to accept Low Consequence-High Frequency Events more readily than High Consequence-Low Frequency Events.
• Need a quantitative method to distinguish between “Perceived Risk” and “Actual Risk.” This method is known as a Risk Analysis.
Nuclear Engineering & Radiation Health Physics Oregon State University
The Move Towards “Risk-Based” Regulation
• A Risk Analysis can answer the following questions:– How can government, industry, community use its “safety”
dollars most effectively to reduce overall risk to its workers or the public it serves?
– How can an industry reduce plant down-time?– How much should be spent on safety improvements?– How can industry minimize the likelihood of occurrence of
a hazard?– What would be the most effective emergency strategies
given the occurrence of a hazard?• Government regulators are now using Risk Analyses
to determine: How safe is safe enough?
Nuclear Engineering & Radiation Health Physics Oregon State University
Risk Analysis
• Risk analysis is a technique of identifying, characterizing, quantifying and evaluating hazards.
• Two Phases:– A qualitative step of identifying,
characterizing and ranking hazards.– A quantitative step of risk evaluation,
which includes estimating likelihood and consequences of hazard occurrence.
Nuclear Engineering & Radiation Health Physics Oregon State University
Probabilistic Risk Assessment (PRA) for Nuclear Power Plants
Nuclear Engineering & Radiation Health Physics Oregon State University
Sequoyah PRA ResultsIdentifying Areas for Safety Improvements
NUREG-1150
Loss of Component Cooling Water
31%
Other1%
Station Blackout5%
Loss of Bus3%
LOCA59%
ATWS1%
Nuclear Engineering & Radiation Health Physics Oregon State University
Grand Gulf PRA Results Identifying Areas for Safety Improvements
NUREG-1150
Station Blackout99%
ATWS1%
Nuclear Engineering & Radiation Health Physics Oregon State University
Surry PRA Results Identifying Areas for Safety Improvements
NUREG-1150Loss of Offsite
Power4%
Loss of Bus20%
LOCA28%
SGTR4%
ATWS6%
Station Blackout38%
Nuclear Engineering & Radiation Health Physics Oregon State University
NRC Safety Goal(Latent Cancer Fatalities NUREG-1150)
Nuclear Engineering & Radiation Health Physics Oregon State University
An Exercise in Funding Public Safety Research
• Organizations– Federal Emergency Management Agency (FEMA)– Nuclear Regulatory Commission (NRC)– Environmental Protection Agency (EPA)– Food and Drug Administration (FDA)– Federal Aviation Administration (FAA)– Federal Bureau of Investigation (FBI)
• Each Team will be asked to share with the class:– What they think are the top 2-3 safety issues their
agency needs to address.– Why they should get funding over other agencies.
Nuclear Engineering & Radiation Health Physics Oregon State University
NRC Safety Goal (Early Fatalities NUREG-1150)
Nuclear Engineering & Radiation Health Physics Oregon State University
Comparison of U.S. Nuclear
Power Plant Risks to Natural Events
WASH-1400 Study
Nuclear Engineering & Radiation Health Physics Oregon State University
Comparison of U.S. Nuclear Power Plant Risks to Man-Made
EventsWASH-1400 Study