Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Development of a Fully-Coupled, All States, All Hazards Level 2 PSA at Leibstadt Nuclear Power Plant

  • Zvoncek, Pavol (Safety Compliance & Technical Support Department, Leibstadt Nuclear Power Plant) ;
  • Nusbaumer, Olivier (Safety Compliance & Technical Support Department, Leibstadt Nuclear Power Plant) ;
  • Torri, Alfred (Risk Management Associates, Inc.)
  • Received : 2016.12.07
  • Accepted : 2017.01.06
  • Published : 2017.04.25
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Abstract

This paper describes the development process, the innovative techniques used and insights gained from the latest integrated, full scope, multistate Level 2 PSA analysis conducted at the Leibstadt Nuclear Power Plant (KKL), Switzerland. KKL is a modern single-unit General Electric Boiling Water Reactor (BWR/6) with Mark III Containment, and a power output of $3600MW_{th}/1200MW_e$, the highest among the five operating reactors in Switzerland. A Level 2 Probabilistic Safety Assessment (PSA) analyses accident phenomena in nuclear power plants, identifies ways in which radioactive releases from plants can occur and estimates release pathways, magnitude and frequency. This paper attempts to give an overview of the advanced modeling techniques that have been developed and implemented for the recent KKL Level 2 PSA update, with the aim of systematizing the analysis and modeling processes, as well as complying with the relatively prescriptive Swiss requirements for PSA. The analysis provides significant insights into the absolute and relative importances of risk contributors and accident prevention and mitigation measures. Thanks to several newly developed techniques and an integrated approach, the KKL Level 2 PSA report exhibits a high degree of reviewability and maintainability, and transparently highlights the most important risk contributors to Large Early Release Frequency (LERF) with respect to initiating events, components, operator actions or seismic component failure probabilities (fragilities).

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References

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