				Search Options
Index \| Site Map \| FAQ \| Facility Info \| Reading Rm \| New \| Help \| Glossary \| Contact Us

Circuit Analysis - Failure Mode and Likelihood Analysis (NUREG/CR-6834)

On this page:

Publication Information
Abstract

Download complete document

The following links on this page are to documents in Adobe Portable Document Format (PDF). See our Plugins, Viewers, and Other Tools page for more information. For successful viewing of PDF documents on our site please be sure to use the latest version of Adobe.

NUREG/CR-6834 (PDF - 2.27 MB)

Publication Information

Manuscript Completed: June 2003
Date Published: September 2003

Prepared by
J.L. LaChance, S.P. Nowlen,
F.J. Wyant, V.J. Dandini

Sandia National Laboratories
Albuquerque, NM 87185-0748

H.W. Woods, NRC Project Manager

Prepared for
Division of Risk Analysis and Applications
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
NRC Job Code Y6037

Availability Notice

Abstract

Under existing probabilistic risk assessment (PRA) methods, the analysis of fire-induced circuit faults has typically been conducted on a simplistic basis. While exceptions do exist, a typical fire PRA will assume that given damage to any power or control cables, the associated circuits simply become unavailable. This approach does not address, for example, the potential that certain failures might cause spurious component actuations. In particular, certain cable failure modes, referred to as hot shorts, might lead to spurious operations. Those fire PRAs that have considered potential spurious operations have relied on methodologies that have significant uncertainties with regard to the scope of the assessments, the underlying methods, and the assumptions employed. Nonetheless, some of these fire PRAs have shown that cable hot shorts can be a significant risk contributor.

This report describes the results of a task to address weaknesses in existing fire PRA circuit analysis methods. An extensive review of available cable failure data has been performed and the current state of knowledge regarding cable failure modes and likelihood is characterized. A framework for advanced methods of cable failure mode and likelihood analysis is also presented. Advanced tools for performing PRA circuit analysis that explicitly treat different cable failure modes and the resulting circuit and system impact are outlined. Example applications of the proposed circuit analysis methods are provided.