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http://dx.doi.org/10.14346/JKOSOS.2021.36.5.86

A Simple Approach to Calculate CDF with Non-rare Events in Seismic PSA Model of Korean Nuclear Power Plants  

Lim, Hak Kyu (Department of NPP Engineering, KEPCO International Nuclear Graduate School)
Publication Information
Journal of the Korean Society of Safety / v.36, no.5, 2021 , pp. 86-91 More about this Journal
Abstract
Calculating the scrutable core damage frequency (CDF) of nuclear power plants is an important component of the seismic probabilistic safety assessment (SPSA). In this work, a simple approach is developed to calculate CDF from minimal cut sets (MCSs) with non-rare events. When conventional calculation methods based on rare event approximations are employed, the CDF of industry SPSA models is significantly overestimated by non-rare events in the MCSs. Recently, quantification algorithms using binary decision diagrams (BDDs) have been introduced to prevent CDF overestimation in the SPSA. However, BDD structures are generated from a small part of whole MCSs due to limited computational memory, and they cannot be reviewed due to their complicated logic structure. This study suggests a simple approach for scrutinizing the CDF calculation based on whole MCSs in the SPSA system analysis model. The proposed approach compares the new results to outputs from existing algorithms, which helps in avoiding CDF overestimation.
Keywords
seismic PSA; non-rare events; overestimation; CDF; nuclear power plants;
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1 P. Zvonceka and O. Nusbaumera, "Comparison of MCUB and MCS BDD Fault Tree Solution Algorithms using Leibstadt Nuclear Power Plant Model", Probabilistic Safety Assessment and Management PSAM 14, Los Angeles, CA, USA, 2018.
2 M. K. Ravindra and C. R. Sundararajan, "Seismic Risk Assessment, Probabilistic Structural Mechanics Handbook-Theory and Industrial Applications", Chapter 19, Springer Science+Business Media Dordrecht, 1995.
3 Kennedy, R.P., Cornell, C.A., Campbell, R.D., Kaplan, S., Perla, H.F., "Probabilistic Seismic Safety Study of an Existing Nuclear Power Plant", Nucl. Eng. & Des., 59(2), pp.315-338, 1980 .   DOI
4 S. K. Park and W. S. Jung, "A New Quantification Method for Multi-Unit Probabilistic Safety Assessment", J. Korean Soc. Saf., Vol. 35, No. 1, pp. 97-106, 2020.   DOI
5 Electric Power Research Institute, "Seismic Probabilistic Risk Assessment Implementation Guide", EPRI 1002989, 2003.
6 Korea Atomic Energy Research Institute, "AIMS-PSA Release 2 Reference Manual", KAERI-ISA-MEMO-AIMS-03-KOR, 2012.
7 Electric Power Research Institute, "FTREX 1.9 Software Manual", EPRI 3002012968, 2018.
8 H. K. Lim, "A Study of System Analysis Method for Seismic PSA of Nuclear Power Plants", J. Korean Soc. Saf., Vol. 34, No. 5, pp. 159-166, 2019.
9 Nuclear Safety and Security Committee, "A Study on System Modeling of Seismic PSA to Prevent Overestimation of Seismic CDF", NSTAR-19NS42-91, 2019.
10 American Society of Mechanical Engineers/American Nuclear Society (ASME/ANS), "Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications Standard for Probabilistic Risk Assessment for Nuclear Power Plant Applications", ASME/ANS-RA-Sa-2009, Addenda to ASME/ANS RA-S-2008, 2009.
11 W. S. Jung, "BeEAST Version 1.1 User Manual", Sejong University, 2017.