NE 319 Societal Aspects of Nuclear Technology How Safe is Safe Enough

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NE 319Societal Aspects of Nuclear Technology
How Safe is Safe Enough?

• Dr. Jose N. Reyes, Jr.
• Department of Nuclear Engineering
• Oregon State University
• Spring Term 2001

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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

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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
in170,000 Risk of dying once infected 1 in 4
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Lightning Risks

• Risk of being struck by Lightning in any given
  year 1 in 750,000
• The chances of surviving 3 in 4

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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.

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An Electrifying Personality

• 1. 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.

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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.

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Survey

• Rank the activities according to your perception
  of the risk involved in participating!
• For Example

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• Occupational Fatalities per 100,000 Employed

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• Sports
• Injuries

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Deaths Due to Injuries in 1992
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How Do You Define Safety?

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

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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.

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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)

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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

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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)

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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)

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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)

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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?

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Attitudes Towards Risk

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

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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.

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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?

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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.

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Probabilistic Risk Assessment (PRA) for Nuclear
Power Plants
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Sequoyah PRA ResultsIdentifying Areas for Safety
ImprovementsNUREG-1150
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Grand Gulf PRA Results Identifying Areas for
Safety ImprovementsNUREG-1150
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Surry PRA Results Identifying Areas for Safety
ImprovementsNUREG-1150
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NRC Safety Goal(Latent Cancer Fatalities
NUREG-1150)
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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.

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NRC Safety Goal (Early Fatalities NUREG-1150)
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• Comparison of U.S. Nuclear Power Plant Risks to
  Natural EventsWASH-1400 Study

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Comparison of U.S. Nuclear Power Plant Risks to
Man-Made EventsWASH-1400 Study