Results of the Level 1 Probabilistic Risk Assessment (PRA) of Internal Events for Heavy Water Production Reactors
Results of the Level 1 Probabilistic Risk Assessment (PRA) of Internal Events for Heavy Water Production Reactors

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Published: 1990

Total Pages: 8

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A full-scope probabilistic risk assessment (PRA) is being performed for the Savannah River site (SRS) production reactors. The Level 1 PRA for the K Reactor has been completed and includes the assessment of reactor systems response to accidents and estimates of the severe core melt frequency (SCMF). The internal events spectrum includes those events related directly to plant systems and safety functions for which transients or failures may initiate an accident. The SRS PRA has three principal objectives: improved understanding of SRS reactor safety issues through discovery and understanding of the mechanisms involved. Improved risk management capability through tools for assessing the safety impact of both current standard operations and proposed revisions. A quantitative measure of the risks posed by SRS reactor operation to employees and the general public, to allow comparison with declared goals and other societal risks.

Level 1 Probabilistic Risk Assessment of Low Power and Shutdown Operations at a PWR
Level 1 Probabilistic Risk Assessment of Low Power and Shutdown Operations at a PWR

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Published: 1992

Total Pages: 10

ISBN-13:

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As a result of the Chernobyl accident and other precursor events (e.g., Diablo Canyon), the US Nuclear Regulatory Commission's (NRC's) Office of Nuclear Regulatory Research (RES) initiated an extensive project during 1989 to carefully examine the potential risks during Low Power and Shutdown (LP S) operations. Shortly after the program began, an event occurred at the Vogtle plant during shutdown, which further intensified the effort of the LP S program. In the LP S program, one pressurized water reactor (PWR), Surry, and one boiling water reactor (BWR), Grand Gulf, were selected, mainly because they were previously analyzed in the NUREG-1150 Study. The Level-1 Program is being performed in two phases. Phase 1 was dedicated to performing a coarse screening level-1 analysis including internal fire and flood. A draft report was completed in November, 1991. In the phase 2 study, mid-loop operations at the Surry plant were analyzed in detail. The objective of this paper is to present the approach of the phase 2 study and the preliminary results and insights.

Advanced Test Reactor Probabilistic Risk Assessment Methodology and Results Summary
Advanced Test Reactor Probabilistic Risk Assessment Methodology and Results Summary

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Published: 1992

Total Pages: 100

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The Advanced Test Reactor (ATR) probabilistic risk assessment (PRA) Level 1 report documents a comprehensive and state-of-the-art study to establish and reduce the risk associated with operation of the ATR, expressed as a mean frequency of fuel damage. The ATR Level 1 PRA effort is unique and outstanding because of its consistent and state-of-the-art treatment of all facets of the risk study, its comprehensive and cost-effective risk reduction effort while the risk baseline was being established, and its thorough and comprehensive documentation. The PRA includes many improvements to the state-of-the-art, including the following: establishment of a comprehensive generic data base for component failures, treatment of initiating event frequencies given significant plant improvements in recent years, performance of efficient identification and screening of fire and flood events using code-assisted vital area analysis, identification and treatment of significant seismic-fire-flood-wind interactions, and modeling of large loss-of-coolant accidents (LOCAs) and experiment loop ruptures leading to direct damage of the ATR core. 18 refs.

Advanced Test Reactor Probabilistic Risk Assessment
Advanced Test Reactor Probabilistic Risk Assessment

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Published: 1993

Total Pages: 6

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This report discusses Level 1 probabilistic risk assessment (PRA) incorporating a full-scope external events analysis which has been completed for the Advanced Test Reactor (ATR) located at the Idaho National Engineering Laboratory.

Communication of Advanced Test Reactor Probabilistic Risk Assessment Results
Communication of Advanced Test Reactor Probabilistic Risk Assessment Results

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Published: 1992

Total Pages: 4

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The Advanced Test Reactor (ATR) probabilistic risk assessment (PRA) Level 1 results were efficiently communicated in two reports following the completion of revision 1 of the ATR PRA. As the ATR PRA including external events fills four large volume, it was considered impractical to expect all of the individuals at ATR who could benefit from the information to read the entire PRA. Even though many ATR personnel received training in PRA methodology and were involved in some aspects of the PRA, another hinderance to effective communication of the PRA results is that the PRA was written and organized to meet the requirements of practitioners and reviewers who are well-versed in PRA methods. Therefore, two PRA summary reports, an ATR risk summary report and an ATR functional group summary report, were written to communicate the ATR PRA results and insights to interested ATR personnel.