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Harmonizing Engineering, EPA, and Terrorism Risk Assessments for Low Probability-High Consequence Events

This article discusses the importance of harmonizing engineering, EPA, and terrorism risk assessments for low probability-high consequence events. It explores the use of event trees and fault trees in nuclear power accidents and the different approaches to risk assessment between EPA and FDA. The article also highlights the need for event tree analysis in other industries and provides suggestions for preventing terrorism scenarios at various stages. Additionally, it addresses the characteristics of terrorists, the importance of keeping weapons out of their hands, and efforts to keep terrorists away from sensitive places.

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Harmonizing Engineering, EPA, and Terrorism Risk Assessments for Low Probability-High Consequence Events

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  1. Low Probability-High Consequence EventsHarmonizing. Engineering, “EPA” and terrorism risk assessments 2nd World Congress on Risk Guadalajara, Mexico June 9th 2008Richard WilsonMallinckrodt Research Professor of PhysicsHarvard University

  2. Rare Nuclear Power accidents first studied by physicistsAdvisory Committee on Reactor Safeguards – Teller, Wigner, and Feynmanonly accidents less than the MAXIMUM CREDIBLE ACCIDENTwere consideredThe landmark Reactor Safety Study (WASH 1400) in 1975was chaired by a physicist (Rasmussen)Looked quantitatively at the extreme events(Low Probability; High Consequence)by a combination of EVENT TREES and FAULT TREES

  3. First task:Define the problem.Next task:break it into manageable component partsfactorizable as much as possibleNuclear Power was the first example

  4. Simplified EVENT TREE for pipe breakRate of Pipe Breaks F1Probability of ECCS (SF) failure P2Probability of Containment Failure P3Probability of wind blowing to City P4IF INDEPENDENTOverall rate = F1x P2 x P3 x P4FAULT TREE can be used to estimate P2,P3

  5. P4 is calculated very differently by an“EPA” (or “FDA”) style risk assessment.What is the permissible dose of a substance before it causes harm?Before 1975 FDA assumed a threshold or Logit response EPA assume a linear dose-response for cancer endpoints..Taylor’s theorem suggests it should be linerar at low doses if the end point is the same naturally and artificially

  6. “EPA” style risk assessmentRadiological effect by epidemiologyNew Chemicals using Animal data In discussing chemical spillsan engineering PRA (event tree)must be used for the front end.Crucial to harmonize the assessementsDo not use different jargon

  7. Are the probabilities coupled?A failure scenario which couples them is called aCommon Mode FailureFire, flood or Earthquake can couple the individual steps At Browns Ferry fire in a cable duct led to loss of control.(solution: use redundant cable ducts)The event tree enables us to focus on these correlations.Now every reactor has a detailed study (Jargon - Probabilistic Risk Analysis -PRA)It enables the analyst to find weak points.In the first PRA (Surry, VA) a simple change for about $50,000 reduced the calculated accident probability by a factor of 5

  8. A saboteur (terrorist) can couple the different stepsRasmussen said in 1978:“There is nothing a terrorist can do that those clowns (operators at TMI ) did not do on their own”.My response:A terrorist can increase the probability!Especially a group of terrorists

  9. A saboteur can :take a nuclear engineering coursework at a nuclear plant as a “sleeper”Then he can set off two bombs(1) To break a pipe and (2) open a containment hole (3) when the wind is blowing to a cityIf 6 terrorists act in concert it is easier

  10. Industries now using Event Tree Analysis1975 Nuclear Power WASH 1400;NUREG 75/014 1978 LNG: Keeney et al Techn. Rev. 81:64 1985 Oil refineries1985 Chemical plants2000 NASA2xxx Building Industry (not yet)Independence of steps not as easy as in nuclear power.

  11. Event Tree Analysis Imagine what a terrorist might do: and devise a system to make it hard for him to do it.Stop the event as early in the chain as possible(dont let trouble spots fester)‏

  12. Suggested Event Scenario(1) Stop creation of terrorists (2) Keep weapons out of hands of terrorists(3) Keep potential terrorists away from sensitive places(4) Make ALL individual targets more secureStop a scenario as early in the event chain as possibleFewer terrorists than targets!

  13. What makes a terrorist?The organized Al Quaeda of 2001 no longer exists(Scott Atran) Now organization by internetMadrid bombing was a group from one area of Moroccoterrorists are like ordinary people2001 terrorists: educated. Not religious(Marc Sageman: “Leaderless Jihad”)Why more terrorist suspects in Europe than USA?Frustration with lack of integration?Watch internet grouping

  14. Step 2.Keep weapons out of the hands of terroristsFirearms are easily available. Even AK7sBut Atomic Bombs?Biological material?Nerve gases?

  15. Step 2 keep weapons out of the hands of terrorists.Only limited possibilities for ordinary weapons - including AK7sESSENTIAL FOR NUCLEAR WEAPONSNot easy for chemicals orbiological materials18Important to prioritize“If you guard your toothbrushes as carefully as you guard your diamonds You will lose fewer toothbrushes butyou will lose more diamonds!”JH Van Vleck (circa 1955)‏

  16. Be careful with fissile material: IAEA records

  17. Step 3.Keeping Terrorists at Arm’s lengthMake it hard to enter the US keeping terrorists away from facilitiesis where US is concentrating effortsInevitably conflicts with liberty and human rightsUSSR system of closed areas – (Chelyabinsk, Sverdlovsk)no longer works

  18. Step 3Importance of SecrecyAs in military matters:Strategic (long term issues) should be openTactics (short term issues) should be on a “need to know”I know, in general, where to fly an airplane to destroy a nuclear power plant, (not the containment vessel)but on individual detail, I do not need to know

  19. Step 4. Making Society Safer AEngineering and Industrial facilitiesDo not store a lot of fuel in one place near a lot of people in the same place. (Wigner 1974) Oil tanks and LNG facilities should be in remote areas. (In 1848 London decided to keep Petroleum products 30 miles from London bridge in Canvey Island)Terrorism and Sabotage already considered for nuclear power.Look at high consequence scenarios in every industry

  20. Natural DISASTERS can SUGGESTNASTY TERRORIST actions(1)Substation failure in Naperville ILL shut down landing system at O'Hare (and cut off my son's E mail)(2) Broken relay shut down NE electricity for 5 hours (1967)(3) Storm cut major transmission lines in France for 4 days(4) 1944 at Clapton Sands off duty US soldiers shot at insulators and shut down the line to Naval base If:20 terrorist sharp shooters each choose a transmission tower in a remote area and at noon each shot at an insulatorMAYBE AT THE SAME TIMEother terrorists release SARIN in subway....Anyone guess the consequence?

  21. Emergency exits are not used in USACoconut Grove Night club in 1941 they were lockedAt the Rhode Island Fire people did not use themFire protection, etc must be practiced.In 1957 Andrea Doria collision in calm weather in fog and sank in 3 hours 100 people diedBritish troopship with families sunk in 1/2 hourengineer killed in explosion all others saved!

  22. Step 4 – Making Life Safer BB Biological Processes Reducing Natural Epidemics also trains people toreduce the risk of biological terrorism1919 Flu; 2005 SARSIn disease spread there are 2 crucial numbers:(i) average number of people a single person infects ~ 2.5(ii) time between infections ~ 10 daysBUT look at exceptionsSome postulated terrorist events are newRadiological bombAnthrax spores dispersed by high explosiveFor these: The first 5 minutes may be crucial

  23. A “dirty bobm” or “Radiological Bomb” will kell only a few but make areas unihabitable (USING POST-CHERNOBYL RULES)A Pandemic (like 1918 flu) can be started by terrorists and can kill 70 million

  24. “If you still want to belong to an organization dedicated to killing Americans, there’s always the tobacco lobby.”Alex Gregory, Cartoonbank.com

  25. Possible “easy” terrorist ActionsAnthrax released in a high explosive bomb upwind of city can kill more people than a plutonium bombSilver cyanide plating solution dumped in reservoir after filtration(possible in Oxford in 1949)Biological material released in subway

  26. Known Terrorist Groupswith Assumed reasons for FrustrationTamil Tigers - Sri LankaIRA - IrelandHamas military wing - Palestine/IsraelHezbollah - LebanonBasque separatists - SpainTaliban – NW Pakistan“If there is hope and you kill a terrorist you have one terrorist lessIf there is no hope and you kill a terrorist you have 10 terrorists more”(Israeli General: Also Yugoslav experience in WWII)‏

  27. Act promptly to reduce (i) from 2.5 to 0.99At least 60% of all people must cooperate(Successes - small pox; Wash handsWear face mask especially infected people (Japan)Don't go to work/school or travel if feverQuarantine; need for societal agreementIn community:radio temperature to central place to identify a cluster of high fever. Then start more drastic action promptly

  28. Airline Pilots will now resist a hijackingBar cockpit doorsMaybe set to control from ground or automaticUse emergency exits regularly“The public may leave at the end of each performance by all exit doors and at that time the doors shall be open”Lord Chamberlain's regulations, UKEasy access to first aid boxesIn a recent inspection in Boston, they were locked up and noone had the key!

  29. Few plans for a major fire at WTC?(FEMA report instructive for what it missed out)Insulation not tested for durabilityFire and initial impact destroyed all safety mechanisms (Common mode failure not foreseen!)Helicopter fire fighters?Protect buildings by cables from towers or balloons?

  30. Some terrorists are now educated. Also some act in concertSabotage and terrorism are unfortunate facts of life.They will be with us until the end of the human race.

  31. We must not let terrorism distort our lives. Other risks are bigger.Car accidents: 45,000/yr vs. 3,500 onceDrugs destroy society moreSecurity vs. Freedom Our human rights are what makes life worth living.

  32. Crucial Importance of Readiness for ResponseIf a terrorist knows that there will be a quick and intelligent responseit will be less attractive

  33. Inspect the insulation of all buildings over 50 stories high.(expensive but possible;e.g. apply a heat source to steel in one location and compare the temperature - time profile with calculation)‏

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