ML19011A440
| ML19011A440 | |
| Person / Time | |
|---|---|
| Issue date: | 01/16/2019 |
| From: | Office of Nuclear Regulatory Research |
| To: | |
| Nathan Siu 415-0744 | |
| Shared Package | |
| ML19011A416 | List:
|
| References | |
| Download: ML19011A440 (24) | |
Text
Risk-Informed Fire Protection Lecture 8-3 1
Overview Key Topics
- Browns Ferry fire
- Fire PRA history
- Risk-informed fire protection
- Current controversies 2
Overview Resources
- U.S. Nuclear Regulatory Commission, The Browns Ferry Nuclear Plant Fire of 1975 Knowledge Management Digest, NUREG/KM-0002, Rev. 1, February 2014.
- S.P. Nowlen, M. Kazarians, and F. Wyant, Risk Methods Insights Gained From Fire Incidents, NUREG/CR-6738, September 2001.
- N. Siu, N. Melly, S. P. Nowlen, and M. Kazarians, Fire Risk Assessment for Nuclear Power Plants, The SFPE Handbook of Fire Protection Engineering, 5th Edition, Springer-Verlag, New York, 2016.
- Nuclear Energy Agency, CSNI Technical Opinion: Fire Probabilistic Safety Safety Assessment for Nuclear Power Plants: 2019 Update, Boulogne-Billancourt, France, in publication.
- N. Siu, K. Coyne, and N. Melly, Fire PRA maturity and realism: a technical technical evaluation, U.S. Nuclear Regulatory Commission, March 2017.
(ADAMS ML17089A537) 3
Overview Other References
- U.S. Code of Federal Regulations, Fire Protection, 10 CFR 50.48, June 16, 2004, last amended Aug. 28, 2007.
- National Fire Protection Association, Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 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 of Nuclear Regulatory Research, EPRI/NRC-RES Fire PRA Methodology for Nuclear Power Facilities, 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 of Nuclear Regulatory Research, Fire Probabilistic Risk Assessment Methods Enhancements: Supplement 1 to NUREG/CR-6850 and EPRI 1011989, 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.
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Overview Other References (cont.)
- M. Kazarians, N. Siu, and G. Apostolakis, Fire risk analysis for nuclear power plants:
methodological developments and applications, Risk Analysis, 5, 33-51, 1985.
- N. Siu, J.T. Chen, and E. Chelliah, Research Needs in Fire Risk Assessment, NUREG/CP-0162, Vol. 2, 25th Water Reactor Safety Information Meeting Bethesda, MD, October 20-22, 1997.
- U.S. Nuclear Regulatory Commission, Perspectives Gained from the Individual Plant Examination of External Events (IPEEE) Program, NUREG-1742, April 2002.
- Nuclear Energy Agency, International Workshop on Fire PRA: Workshop Proceedings, NEA/CSNI/R(2015)12, Boulogne-Billancourt, France, 2015. (Available from:
http://www.oecd-nea.org/nsd/docs/indexcsni.html)
- B. McGrattan, et al., Fire Protection and Fire Research Knowledge Management Digest, 2013, NUREG/KM-0003, 2013.
- N. Siu, Fire Risk Assessment for Nuclear Power Plants, FPE 580R - Fire Risk Assessment and Policy, Worcester Polytechnic Institute, December 2, 2015. (ADAMS ML15301A832)
- N. Siu, PSA Heterogeneity: Implications for Risk Aggregation, IAEA Consultancy Meeting on Development of a Methodology for Aggregation of Various Risk Contributors for Nuclear Facilities, International Atomic Energy Agency, Vienna, Austria, April 10-13, 2017. (ADAMS ML17093A744) 5
Risk-Informed Regulations 6
Browns Ferry Fire How it started Adapted from NUREG-0050
- Browns Ferry Nuclear Power Plant (3/22/75)
- Candle initiated cable tray fire; 11.5m 8.5m water suppression delayed; complicated shutdown
- Second-most challenging event in U.S. nuclear power plant 3m operating history
- Spurred changes in requirements and analysis 7
Browns Ferry Fire Browns Ferry (March 22, 1975) 8
Browns Ferry Fire Fire Protection After Browns Ferry
- Post-Browns Ferry deterministic fire protection (10 CFR Part 50, App R) hour fire barrier, OR
- 20 feet separation with detectors and auto suppression, OR hour fire barrier with detectors and auto suppression
- Concerns
- Equivalence of protection methods:
whats best?
foot criterion: how protective?
- Possible to make win-win trade-offs?
- License by exemption?
From Cline, D.D., et al., Investigation of Twenty-Foot Separation Distance as a Fire Protection Method as Specified in 10 CFR 50, Appendix R, NUREG/CR-3192, 1983.
9
Fire PRA/RIDM History Early Fire PRAs
- Early cable spreading room analyses
- WASH-1400
- Physical model for fire-induced damage
- Incorporation in PRA via competing processes model (growth vs.
Professor George Apostolakis, UCLA suppression) (UCLA School of Engineering)
- Used and refined in Zion and Indian Point PRAs
- Framework and tools for subsequent analyses (NUREG-1150, IPEEEs) 10
Fire PRA/RIDM History Early Results - Fire Can Be Important Or Even Dominant Contributor to CDF 11
Fire PRA/RIDM History Near Misses - Empirical Support for Results Event Summary Description*
Browns Ferry Multi-unit cable fire; multiple systems lost, spurious component and system (BWR, 1975) operations; makeup from CRD pump Electrical cable fire; station blackout (SBO), loss of all normal core cooling for 5 Greifswald hours, loss of coolant through valve; recovered through low pressure pumps and (VVER, 1975) cross-tie with Unit 2 Turbine lube oil fire , collapsed turbine building roof, propagated into control Beloyarsk (LWGR, building, main control room (MCR) damage, secondary fires; extinguished in 22 1978) hours; damage to multiple safety systems and instrumentation.
Electrical cable fire (multiple locations), smoke spread to Unit 1 MCR, secondary Armenia explosions and fire; SBO (hose streams), loss of instrumentation and reactor (VVER, 1982) control; temporary cable from emergency diesel generator to high pressure pump Chernobyl (RBMK, Turbine failure and fire, turbine building roof collapsed; loss of generators, loss of 1991) feedwater (direct and indirect causes); makeup from seal water supply Narora Turbine failure, explosion and fire, smoke forced abandonment of shared MCR; (PHWR, 1993) SBO, loss of instrumentation; shutdown cooling pump energized 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) 12
Fire PRA/RIDM History Risk-Informed Fire Protection (NFPA 805)
- Difficulties with deterministic compliance with Appendix R => exemptions
- Risk-informed approach
- Alternative method for regulatory compliance
- Additional benefits: improved understanding of sources of fire risk, 10 CFR 50.48(c)(3)
- Risk-informed, performance-based fire protection (10 CFR 50.48(c), NFPA 805) Making Sausage Standard and regulatory approach
- Voluntary alternative to Appendix R development
- Deterministic and performance-based
- Consensus process elements
- Multiple stakeholders, diverse views (incl. strong PRA critics)
- Changes can be made without prior
- Good enough for immediate approval; risk must be acceptable problem 13
Fire PRA/RIDM History Fire PRA R&D
- Restarted in 1997
- Better understanding of fire risk
- Improved support of regulatory activities
- Methods and tools
- Near- and long-term issues, e.g.,
- Multiple spurious operations
- Lessons from operational events
- Fire risk requantification task (to assess impact of methodological improvements) => guidance development (joint with EPRI) to support NFPA 805 NUREG/CR-6850/EPRI TR1011989
- Major disruption: 9/11 14
Fire PRA/RIDM History Fire R&D: The Laundry List (c. 1998) 15
Fire PRA/RIDM History Fire PRAs - More Recent Results 16
Fire PRA/RIDM History Fire PRAs - Risk Contributors From: K. Voelsing, EPRI Fire PRA Research Plan, U.S. Nuclear Regulatory Commission Regulatory Information Conference, March 15, 2018. 17
Fire PRA/RIDM History Recap: Fire PRA/RIDM in the U.S.
Industry Full-Scope PRAs IPEEEs NFPA 805 LARs Browns Ferry fire NFPA 805, 10 CFR 50.48(c),
RG 1.205, NEI 04-02, EPRI 1011989/NUREG/CR-6850, NUREG-1150/RMIEP (WASH-1400 analysis)
Fire PRA R&D 1975 1980 1985 1990 1995 2000 2005 2010 2015 18
Current Challenges A Heated Debate
- Is fire PRA mature? Are the results overly conservative?
- Industry concerns
- Expense of detailed analyses
- Realism of specific sub-models
- Flexibility in making plant changes
- Implications for other risk-informed applications
- NRC concerns
- Technical basis for alternative models RG 1.174, Revision 3
- Implications for other risk-informed applications 19
Current Challenges Common View: The Need for Realism
- Excessive conservatism or optimism can
- Inappropriately focus decision maker attention
- Lead to wasteful or even problematic solutions
- Mask opportunities for other improvements
- Damage stakeholder confidence
?
20
Current Challenges Current Issues - An Example
- High Energy Arcing Faults (HEAF) in cabinets
- Operational events, e.g.,
- Maanshan (2001)
- Robinson (2010)
- Onagawa (2011)
- Potentially important contributor to fire risk
- Multi-national experimental program 21
Current Challenges Where are we now?
- Completed transitions to NFPA 805 (> 1/3 fleet)
- Use of fire PRA methods by international organizations
- Cooperative data collection and R&D to address some issues
- Debates over appropriate R&D for others
- Debates over proper aggregation of results from heterogeneous analyses 22
Current Challenges On Aggregation
- Heterogeneity sources in a practical PRA:
- Multiple technical disciplines
- Different states of knowledge
- Different views on what needs to be and what can be reasonably modeled
- Different views on acceptable modeling approaches
- Different views on treatment of uncertainty
- Limited project resources
- Numerical results need to be provided in context 23
Comments
- Multiple technical cultures with varying/divergent views on appropriate use of risk information + need for expediency =>
- Compromise solutions that might not be good enough for other applications
- Different solutions for different technical domains (and technical cultures)
- Personal concern: myopic tactics can have short-term success but also social impacts that hurt fundamental, long-term acceptance (let alone support) of PRA and RIDM
- Sound-bite characterization of issues
- Goal-directed R&D (reducing conservatism vs. improving realism)
- Marginalization of stakeholders 24