Risk-Reduction Credit for Very Early Warning Fire Detection at Nuclear Power Plants: From FAQ to Fiction
In 2004, the U.S. Nuclear Regulatory Commission (NRC), with support from the commercial nuclear power industry, adopted the 2001 Edition of National Fire Protection Association (NFPA) Standard 805, “Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants,” as the means by which commercial nuclear power licensees could comply with Title 10 of the Code of Federal Regulations, Part 50.48(c), to replace deterministic fire protection licensing bases with ones that are risk-informed and performance-based. To facilitate licensee “transitions” to the new licensing bases via NFPA 805, a “Frequently Asked Questions” (FAQs) program, established early during the pilot-plant phase, was expanded to enable use of consensus technical “short-cuts” for fire probabilistic risk assessment (PRA) methods. These “Fire PRA FAQs” enabled licensees, with NRC approval, to bypass more traditional means of establishing acceptable PRA method enhancements on an interim basis, pending eventual confirmation by test programs and/or more detailed analyses. The NRC approved several, of which perhaps the most substantial in providing risk reduction benefits was FAQ 08-0046 on “Incipient Fire Detection Systems,” more accurately characterized as “Very Early Warning Fire Detection Systems” (VEWFDSs). Controversial from the start, the hidden story behind this FAQ’s initial adoption is relevant to examination of the NRC NUREG report that later replaced it and remains in effect today. This article examines this backstory, tracing recommendations that were proposed and bypassed, then examines alternatives to the current guidance. These alternatives, which maximize possible risk reduction credit for VEWFDSs at nuclear power plants, remain at least a factor of two less than the current peak NUREG-2180 risk-reduction factor even before the latter accounts for the possibility of fire pre-emption altogether.
National Fire Protection Association, “Standard NFPA-805: Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants” (2001 Edition).
USNRC and EPRI, “NUREG/CR-6850 (EPRI 1011989): Fire PRA Methodology for Nuclear Power Facilities” (2005), with Supplements.
USNRC, “RG 1.174: An Approach for Using Probabilistic Risk Assessment [PRA] in Risk-Informed Decisions on Plant Specific Changes to the Licensing Basis” (May 2011, Rev. 2; January 2018, Rev. 3).
USNRC, “Close-out of National Fire Protection Association 805 Frequently Asked Question 08-0046 on Incipient Fire Detection Systems,” November 24, 2009 (NRC ADAMS Accession No. ML0903220426).
EPRI, “Report 1016735, Fire PRA Methods Enhancements” (December 2008).
Gallucci, Raymond, et al., “Credit for Very Early Warning Fire Detection (VEWFD) in Fire Probabilistic Risk Assessment,” Proceedings of Risk Management - for Tomorrow's Challenges, American Nuclear Society, 2011, LaGrange Park, Illinois, pp. 152-166.
USNRC, “NUREG-2180: Determining the Effectiveness, Limitations, and Operator Response for VEWFD Systems in Nuclear Facilities (DELORES-VEWFIRE)” (December 2016).
USNRC, NCP-2016-17, “Non-Concurrence: Response to July 28, 2016, Letter Regarding Retirement of National Fire Protection Association Frequently Asked Question 08-0046 ‘Incipient Fire Detection Systems’," November 22, 2016 (NRC ADAMS Accession No. ML16327A451).
Taylor, Gabriel, Raymond Gallucci, et al. “Statistical Characterization of the Advanced Notification in Detection Time for Very Early Warning Fire Detection in Nuclear Plant Electrical Enclosures,” American Nuclear Society 2015 International Topical Meeting on Probabilistic Safety Assessment and Analysis, April 26-30, 2015, Sun Valley, Idaho, pp. 227-235.
National Fire Protection Association, “Standard NFPA-76: Standard for the Fire Protection of Telecommunications Facilities” (2016 Edition).
Joseph Giitter (USNRC), “Letter to M. Tschiltz: NEI Retirement of National Fire Protection Association 805 Frequently Asked Question 08-0046 ‘Incipient Fire Detection Systems’,” July 1, 2016 (NRC ADAMS Accession No. ML16167A444).
USNRC, DPO 2016-004, “Differing Professional Opinion Regarding Retirement of National Fire Protection Association 805 Frequently Asked Question 08-0046,” February 8, 2018 (NRC ADAMS Accession No. ML18039A734).
Joseph Giitter (USNRC), “Letter to M. Tschiltz: “Response to July 28, 2016, Letter Regarding Retirement of National Fire Protection Association 805 Frequently Asked Question 08-0046 ‘Incipient Fire Detection Systems’,” November 17, 2016 (NRC ADAMS Accession No. ML16167A444).
USNRC and EPRI, “NUREG-2169 (EPRI 3002002936): Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated Fire Events Database” (October 2014).
- There are currently no refbacks.
Copyright (c) 2019 Raymond HV Gallucci
This work is licensed under a Creative Commons Attribution 4.0 International License.