ML091070224

Riv Regional Administrator Presentation at Texas A&M University March 30, 2009, Three Mile Island - Impact on Safety Perspectives and Safety Belief

ML091070224
Person / Time
Site:	Three Mile Island
Issue date:	04/17/2009
From:	Collins E NRC Region 4
To:
References
Download: ML091070224 (30)

Text

UNITED STATES NU C LE AR RE G ULATO RY C O M M I S S I O N R E GI ON I V 612 EAST LAMAR BLVD , SU ITE 400 AR LI N GTON , TEXAS 76011-4125 April 17, 2009 MEMORANDUM TO: File FROM: Elmo E. Collins, Regional Administrator (/RA/)

SUBJECT:

RIV REGIONAL ADMINISTRATOR PRESENTATION AT TEXAS A&M UNIVERSITY MARCH 30, 2009, re: THREE MILE ISLAND - IMPACT ON SAFETY PERSPECTIVES AND SAFETY BELIEF

Three Mile Island - Impact on Safety Perspectives and Safety Belief Elmo Collins U.S. NRC Region IV Adams ML#: ML091070224

Three Mile Island Accident March 28, 1979 Series of minor equipment problems Operator Errors Signficant Reactor Core Damage Public Relations

Impact of the Accident Shocked the nuclear establishment Shocked the public Shattered the Commercial Industrys and the regulators perspectives on safety

Safety NUCLEAR POWER PLANT OPS HAZARD

Safety Message (before TMI Accident)

Major radiation releasing accidents are impossible

Basis for Safety Message Before TMI Accident Design Basis Accidents Body of Regulatory Requirements is sufficient

Safety Before TMI Accident NUCLEAR POWER PLANT OPS for everything weve postulated HAZARD

Belief of the Safety Message Before TMI Accident Its not possible

Questions about Safety Basis Before TMI Accident Have you accounted for every eventuality?

Do you know enough about this complex hazardous technology?

Probability and Safety Basis Probabilistic Risk Assessment AEC Reactor Safety Study - 1974 (Rasmussen, WASH-1400)

Safety Basis and Probability Before TMI Accident Numeric quantification - relative comparison of risk Maximum Credible accident - too unlikely for consideration

Safety Before TMI Accident NUCLEAR POWER PLANT OPS For postulated or reasonable events HAZARD

Safety Message - Modified (before TMI Accident)

Maximum credible accidents beyond design basis which could lead to major radiation releases are less than one in a million

Belief of the Safety Message Before TMI Accident Its not possible

Questions about Probability and Safety Before TMI Accident How are you calculating probabilities?

Is it OK to acknowledge that major accidents are possible?

TMI Accident - March 28, 1979 HAZARD OCCURRED!!

Belief of Safety SHATTERED!

IT IS POSSIBLE!

Post-TMI Accident Its more than design Operations Equipment reliability (maintenance)

Its more than the minimum regulatory requirements

Belief Changed There is a difference between believing that accidents can happen and not believing it..Thats the way Ive been conducting myself.it was a mistake. It was wrong.

Roger Mattson Director, NRC Division of Systems Safety

Post-TMI Accident Regulatory Function of Assessment born Resident Inspectors station at every NPP Human Factors are important

Today NRCs Reactor Oversight Process Seven Cornerstones of Safety Bulk of effort -

Initiating Events Mitigating Systems Barrier Integrity

Basis for Safety Enhanced safety measures put in place after TMI Accident Additional events analyzed Risk analysis tools refined to inform decisions Enhanced oversight to confirm implementation of safety measures (NRC and industry)

Safety NUCLEAR POWER PLANT OPS For postulated or reasonable events Vigilant implementation of measures HAZARD

Safety Message Accidents are possible. Safety measures, if reasonably implemented, will prevent the accident NRC strategic goal is to prevent accident

Belief of Safety Message Accidents are possible They can be prevented

Belief of Safety Message These fundamental assumptions and beliefs about the business drives organizational safety performance

Summary TMI Accident showed that safe plant operation is not a given Design is necessary, but not sufficient by itself for safe plant operation Believing that serious accidents are possible is necessary to establish the mind-set for safe operation

References In Search of Safety an excerpt from BEYOND ENGINEERING: How Society Shapes Technology by Robert Pool Managing the Risks of Organizational Accidents, James Reason

Questions?