Electrical Cable Test Results and Analysis During Fire Exposure (ELECTRA-FIRE), A Consolidation of Three Major Fire-Induced Circuit and Cable Failure Experiments Performed Between 2001 and 2011 (NUREG-2128)
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Manuscript Completed: April 2012
Date Published: June 2012
G. Taylor¹, N. Melly¹, H. Woods¹, and T. Pennywell¹
T. Olivier² and C. Lopez²
¹NRC, Office of Nuclear Regulatory Research
²Sandia National Laboratories
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
Over the past 10 years, there have been three major test programs exploring realistic electrical functionality of electrical cables under fire conditions. The three programs were:
- The Electric Power Research Institute (EPRI) and the Nuclear Energy Institute (NEI),
- Comprehensive research and test efforts undertaken jointly by EPRI and NEI to investigate, characterize, and quantify fire-induced circuit failures.
- NRC Cable Response to Live Fire (CAROLFIRE), 2008
- CAROLFIRE was started at the end of the EPRI/NEI test program. It provides an experimental basis for resolving five of the six items identified as “Bin 2” circuit configurations in Regulatory Issue Summary (RIS) 2004-003, “Risk-Informed Approach for Post-Fire Safe-Shutdown Circuit Inspections.”
- Improved fire modeling tools for the prediction of cable damage under fire conditions.
- NRC Direct Current Electrical Shorting in Response to Exposure Fire (DESIREE-FIRE),
- Provides fire-induced cable failures modes and effects data for dc-powered control circuits.
Corresponding EPRI and U.S. Nuclear Regulatory Commission (NRC) technical reports document the test results; however, only the EPRI tests provided an evaluation of various parameters affecting the likelihood of cable failure modes. However, these evaluations were based on a limited set of test data (18 tests). Since then, NRC-sponsored testing has added several hundred data points on the electrical failure characteristics of electrical cable exposure to severe thermal conditions. Evaluating these and other parameters using all available test data would improve understanding of the effects of various parameters on cable failure modes. During an electrical expert Phenomena Identification and Ranking Table (PIRT) meeting in 2011, it became apparent that having individual experts independently analyze the three data sets to derive conclusions to support the PIRT was inefficient and impractical. Thus, the NRC, with support from EPRI and Sandia National Laboratories (SNL), began a project to analyze and catalogue the whole experimental data set to allow the PIRT panel members to make responsible technical decisions. This report documents the background work that was done to analyze the data sets and provides the results in tabular and graphical formats. The objective of this report is to present the data in a factual and coherent format to allow the PIRT panel members to make their best informed decisions. As such, the data set as a whole was analyzed and the authors did not attempt to remove outliers, conduct any specific detailed statistical analysis, or perform other probabilistic methods to arrive at the conclusions in this report. The authors limited their interpretation of the results to report only factual test information.