Methods for Applying Risk Analysis to Fire Scenarios (MARIAFIRES) – 2008: NRC-RES/EPRI Fire PRA Workshop, Final Report, Volume 2 – Module 2: Electrical Analysis (NUREG/CP-0194, EPRI 1020621)

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Publication Information

Date Published: July 2010

Prepared by:
David Stroup
Felix Gonzalez
Hugh Woods

U.S. Nuclear Regulatory Commission
Office of Nuclear Regulatory Research
Washington, DC 20555-0001

U.S. NRC-RES Project Manager
M. H. Salley

Electric Power Research Institute
3420 Hillview Avenue
Palo Alto, CA 94303

EPRI Project Manager
R. P. Kassawar

Availability Notice


The U.S. Nuclear Regulatory Commission (NRC) approved the risk-informed and performance-based alternative regulation 10 CFR 50.48(c) in July 2004, which allows licensees the option of using fire protection requirements contained in the National Fire Protection Association (NFPA) Standard 805, "Performance Based Standard for Fire Protection for Light-Water Reactor Electric Generating Plants, 2001 Edition," with certain exceptions. To support licensees's use of that option, NRC and the Electric Power Research Institute (EPRI) jointly issued NUREG/CR-6850 (EPRI 1011989) "Fire PRA Methodology for Nuclear Power Facilities," in September 2005. That report documents the state-of-the art methods, tools, and data for conducting a fire probabilistic risk assessment (PRA) in a commercial nuclear power plant (NPP) application. The report is intended to serve the needs of a fire risk analysis team by providing a general framework for conduct of the overall analysis as well as specific recommended practices to address each key aspect of the analysis. Participants from the U.S. nuclear power industry supported demonstration analyses and provided peer review of the program. Methodological issues raised in past fire risk analyses, including the Individual Plant Examination of External Events fire analyses, are addressed to the extent allowed by the current state-of-the-art and the overall project scope. Although the primary objective of the report is to consolidate existing state-of-the-art methods, in many areas, the newly documented methods represent a significant advance over previous methods.

NUREG/CR-6850 does not constitute regulatory requirements, and NRC participation in this study neither constitutes nor implies regulatory approval of applications based on the analysis contained in this document. The analyses/methods documented in this report represent the combined efforts of individuals from RES and EPRI. Both organizations provided specialists in the use of fire PRA to support this work. The results from this combined effort do not constitute either a regulatory position or regulatory guidance.

In addition, NUREG/CR-6850 can be used for risk-informed, performance-based approaches and insights to support fire protection regulatory decision-making in general.

On 14-16 June 2005, NRC's Office of Nuclear Regulatory Research (RES) and EPRI conducted a joint public workshop for about 80 attendees at the EPRI NDE Center in Charlotte, NC. A second workshop was held the following year, on 24-26 May 2006, in NRC's Two White Flint North Auditorium in Rockville, MD. About 130 people attended the second workshop. Based on the positive public response to these two workshops, a more detailed training class was developed by the authors of NUREG/CR-6850. Two detailed training workshops were conducted in 2007: on 23-27 July and again on 27-30 August, both at EPRI in Palo Alto, CA. About 100 people attended each of these workshops. In 2008, two more workshops were held from 29 September through 2 October, and again from 17-20 November in Bethesda, MD, near NRC Headquarters. The two workshops attracted about 170 participants including domestic representatives from NRC Headquarters and all four regional offices, U.S. Department of Energy, National Aeronautics and Space Administration, EPRI, NPP licensees/utilities, Nuclear Steam Supply System vendors, consulting engineering firms, and universities. Also in attendance were international representatives from Belgium, Canada, France, Japan, South Korea, Spain, and Sweden.

The material in this NUREG/CP was recorded at the workshops in 2008 and adapted by RES Fire Research Branch members for use as an alternative training method for those who were unable to physically attend the training sessions. This report can also serve as a refresher for those who attended one or more training sessions and would be useful preparatory material for those planning to attend a session.

NRC Disclaimer: This document's text and video content are intended solely for use as training tools. No portions of their content are intended to represent NRC conclusions or Regulatory Positions, and they should not be interpreted as such.

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