Lecture 5-Societal Aspects of Nuclear Technology

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


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


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


Lightning Risks

• Risk of being struck by Lightning in any given year: 1 in 750,000

• The chances of surviving: 3 in 4


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.


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.


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.


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


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


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


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


How Do You Define Safety?

• “Safety” is the relative absence of the risk of realizing a set of undesirable consequences.


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.


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)


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


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)


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)



• 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)



• 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?



• Acceptability Towards Risk depends on:– Benefits of Activity– Voluntary Nature of Activity– Perception– Consequence Distribution



• 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.


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?


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.


Probabilistic Risk Assessment (PRA) for Nuclear Power Plants


Sequoyah PRA ResultsIdentifying Areas for Safety Improvements

NUREG-1150

Loss of Component Cooling Water

31%

Other1%

Station Blackout5%

Loss of Bus3%

LOCA59%

ATWS1%


Grand Gulf PRA Results Identifying Areas for Safety Improvements

NUREG-1150

Station Blackout99%

ATWS1%


Surry PRA Results Identifying Areas for Safety Improvements

NUREG-1150Loss of Offsite

Power4%

Loss of Bus20%

LOCA28%

SGTR4%

ATWS6%

Station Blackout38%


NRC Safety Goal(Latent Cancer Fatalities NUREG-1150)


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.


NRC Safety Goal (Early Fatalities NUREG-1150)


Comparison of U.S. Nuclear

Power Plant Risks to Natural Events

WASH-1400 Study


Comparison of U.S. Nuclear Power Plant Risks to Man-Made

EventsWASH-1400 Study

Education

Lecture 5-Societal Aspects of Nuclear Technology