ML19011A440

Lecture 8-3 Fire Protection 2019-01-22

ML19011A440
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Issue date:	01/16/2019
From:	Office of Nuclear Regulatory Research
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Nathan Siu 415-0744
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Lecture 8-31 Browns Ferry fireFire PRA historyRisk-informed fire protectionCurrent controversies2 Resources3Overview 10 CFR 50.48, June 16, 2004, last amended Aug. 28, 2007.-Based Standard for Fire NFPA 805, 2001 Edition, Quincy, MA, 2001. (Available through the NFPA Online Catalog at www.nfpa.org) Electric Power Research Institute and U.S. Nuclear Regulatory Commission Office -RES Fire PRA Methodology for EPRI 1011989 and NUREG/CR-6850, Electric Power Research Institute (EPRI), Palo Alto, CA and U.S. Nuclear Regulatory Commission, Washington, DC, 2005.Electric Power Research Institute and U.S. Nuclear Regulatory Commission Office Enhancements: Supplement 1 to NUREG/CR-EPRI 1019259 and NUREG/CR-6850 Supplement 1, Electric Power Research Institute (EPRI), Palo Alto, CA and U.S. Nuclear Regulatory Commission, Washington, DC, 2009.4 Other References (cont.)5Overview 6

7Browns Ferry Fire Browns Ferry (March 22, 1975)Browns Ferry Fire Browns Ferry Fire Professor George Apostolakis, UCLA(UCLA School of Engineering)Early cable spreading room analysesWASH-1400HTGR PRANRC-sponsored, post-Browns Ferry R&D at UCLA => fire PRA methodologyPhysical model for fire-induced damageIncorporation in PRA via competing processes model (growth vs. suppression)Used and refined in Zion and Indian Point PRAsFramework and tools for subsequent analyses (NUREG-1150, IPEEEs)

Fire PRA/RIDM History Empirical Support for ResultsEventSummary Description*Browns Ferry(BWR, 1975)Multi-unit cable fire; multiple systems lost, spurious component and system operations; makeup from CRD pumpGreifswald(VVER, 1975)Electrical cable fire;station blackout (SBO), loss of all normal core cooling for 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, loss of coolant through valve; recovered through low pressure pumps and cross-tie with Unit 2Beloyarsk(LWGR, 1978)Turbine lube oil fire ,collapsed turbine building roof, propagated into control building, main control room (MCR) damage, secondary fires;extinguished in 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />; damage to multiple safety systems and instrumentation.Armenia(VVER, 1982)Electrical cable fire (multiple locations), smoke spread to Unit 1 MCR,secondary explosionsand fire; SBO (hose streams),loss of instrumentation and reactor control; temporary cable from emergency diesel generator to high pressure pump Chernobyl(RBMK, 1991)Turbine failure and fire, turbine building roof collapsed;loss of generators, loss of feedwater(direct and indirect causes); makeup from seal water supplyNarora(PHWR, 1993)Turbine failure, explosion and fire, smoke forced abandonment of shared MCR; SBO, loss of instrumentation; shutdown cooling pumpenergized 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br /> later*See NUREG/CR-6738 (2001), IAEA-TECDOC-1421 (2004)

Risk-Fire PRA/RIDM HistoryStandard and regulatory approach development Consensus processMultiple stakeholders, diverse views (incl. strong PRA critics)problem Fire PRA R&D14 15 Fire PRAs More Recent ResultsFire PRA/RIDM History From: K. VoelsingInformation Conference, March 15, 2018.Fire PRA/RIDM History 181980199520002005Browns Ferry fire(WASH-1400 analysis)IndustryFull-Scope PRAsNUREG-1150/RMIEPNFPA 805, 10 CFR 50.48(c),RG 1.205, NEI 04-02,EPRI 1011989/NUREG/CR-Current ChallengesRG 1.174, Revision 3 Excessive conservatism or optimism canInappropriately focus decision maker attentionMask opportunities for other improvementsDamage stakeholder confidence?

High Energy Arcing Faults (HEAF) in cabinetsOperational events, e.g.,Maanshan(2001)Robinson (2010)Onagawa(2011)Potentially important contributor to fire riskMulti-national experimental program21 Where are we now?22 Heterogeneity sources in a practical PRA:Multiple technical disciplinesDifferent states of knowledgeDifferent views on what needs to be and what can be reasonably modeledDifferent views on acceptable modeling approachesDifferent views on treatment of uncertaintyLimited project resourcesNumerical results need to be provided in context23 Comments24