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U.S. Department of Energy
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Practical insights and lessons learned from implementing a seismic margins approach to an IPEEE relay evaluation

Conference ·
OSTI ID:404354
; ; ;  [1]
  1. Science Applications International Corp., Raleigh, NC (United States)
The Nuclear Regulatory Commission`s (NRC) guidance, NUREG-1407, on performing Individual Plant Examinations for External Events (IPEEE) allows a Seismic Margins Assessment (SMA) to address the IPEEE seismic issue regarding the survivability of plant equipment during a seismic event and the capability of the plant to safely shutdown following the seismic event. The NRC guidance further allows the use of the NRC SMA approach or the Electric Power Research (EPRI) approach to evaluate these issues. In addition, the NRC`s Unresolved Safety Issue A-46 (USI A-46) can also be efficiently addressed with the EPRI SMA evaluation. These methodologies are useful in determining a minimum list of equipment required for safe shutdown (i.e., Safe Shutdown Equipment Lists). The resultant Safe Shutdown Equipment List, SSEL, is used to identify the electrically powered equipment required for safe shutdown for which a relay evaluation is required. The evaluation of relays associated with safe shutdown equipment is necessary since equipment can fail to operate properly due to mechanical failure or improper operation/actuation due to relay failure. SAIC has performed relay evaluations on five nuclear power plants. This paper is intended to summarize the practical insights and lessons learned from use of the EPRI SMA approach.
OSTI ID:
404354
Report Number(s):
CONF-960706--; ISBN 0-7918-1787-3
Country of Publication:
United States
Language:
English