Auxiliary feedwater system risk-based inspection guide for the Diablo Canyon Unit 1 Nuclear Power Plant
This document presents a compilation of auxiliary feedwater (AFW) system failure information which has been screened for risk significance in terms of failure frequency and degradation of system performance. It is a risk-prioritized listing of failure events and their causes that are significant enough to warrant consideration in inspection planning at Diablo Canyon. This information is presented to provide inspectors with increased resources for inspection planning at Diablo Canyon. The risk importance of various component failure modes was identified by analysis of the results of probabilistic risk assessments (PRAs) for many pressurized water reactors (PWRs). However, the component failure categories identified in PRAs are rather broad, because the failure data used in the PRAs is an aggregate of many individual failures having a variety of root causes. In order to help inspectors to focus on specific aspects of component operation, maintenance and design which might cause these failures, an extensive review of component failure information was performed to identify and rank the root causes of these component failures. Both Diablo Canyon and industry-wide failure information was analyzed. Failure causes were sorted on the basis of frequency of occurrence and seriousness of consequence, and categorized as common cause failures, human errors, design problems, or component failures. This information permits an inspector to concentrate on components important to the prevention of core damage. Other components which perform essential functions, but which are not included because of high reliability or redundancy, must also be addressed to ensure that degradation does not increase their failure probabilities, and hence their risk importances. 23 refs., 1 fig., 1 tab.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (USA). Div. of Radiation Protection and Emergency Preparedness; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USNRC
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 6546020
- Report Number(s):
- NUREG/CR-5616; PNL-7351; ON: TI91000762; TRN: 91-000897
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
DIABLO CANYON-1 REACTOR
AUXILIARY SYSTEMS
FEEDWATER
FAILURES
HUMAN FACTORS
INSPECTION
PUMPS
REACTOR COMPONENTS
REACTOR SAFETY
RISK ASSESSMENT
VALVES
CONTROL EQUIPMENT
EQUIPMENT
FLOW REGULATORS
HYDROGEN COMPOUNDS
OXYGEN COMPOUNDS
POWER REACTORS
PWR TYPE REACTORS
REACTORS
SAFETY
WATER
WATER COOLED REACTORS
WATER MODERATED REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled