Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
권호 표지

ATWS Frequency Quantification Focusing on Digital I&C Failures

  • Published : 2004.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

The multi-tasking feature of digital I&C equipment could increase risk concentration because the I&C equipment affects the actuation of the safety functions in several ways. Anticipated Transient without Scram (ATWS) is a typical case of safety function failure in nuclear power plants. In a conventional analysis, mechanical failures are treated as the main contributors of the ATWS. This paper quantitatively presents the probability of the ATWS based on a fault tree analysis of a Korea Standard Nuclear Power Plant is also presented. An analysis of the digital equipment in the digital plant protection system. The results show that the digital system severely affects the ATWS frequency. We also present the results of a sensitivity study, which show the effects of the important factors, and discuss the dependency between human operator failure and digital equipment failure.

Keywords

References

  1. KEPCO, Full scope level 2 PSA for Ulchin unit 3&4: Internal event analysis, (1998)
  2. Kang, H.G., et aI., Reliability Study: Digital Reactor Protection System of Korean Standard Nuclear Power Plant, KAERI/TR-2419/2003, Korea Atomic Energy Research Institute, (2003)
  3. Kang, H.G. and Sung, T., 'An analysis of safety-critical digital systems for risk-informed design,' Reliability Engineering and Systems Safety, Vol. 78, (2002) https://doi.org/10.1016/S0951-8320(02)00176-X
  4. K.D. Kim, J.J. Jeong, S.Y. Mo, Y.G. Lee and C.B. Lee, 'A visual environment for system analysis codes,' Progress in Nuclear Energy, Vol. 39, (2001) https://doi.org/10.1016/S0149-1970(01)00018-X
  5. ANS, Time response design criteria for safetyrelated operator actions, ANSI/ANS-58.8, (1994)
  6. Seung-Cheol Jang, et aI., Development of risk model for the Korean standard nuclear power plant, KAERI/TR, To be published, (2004)
  7. Sang Hoon Han, et aI., 'User's Manual for KIRAP (KAERI Integrated Reliability Analysis code Package) Release 2.0,' KAERI/TR-361/93, (1993)
  8. Kang, H.G., Jang, S.C. and Ha, J.J., 'Evaluation of the Impact of the Digital Safety-Critical I&C Systems on the Plant Risk,' Proceeding of ISOFIC 2002, Seoul, Korea
  9. Kang, H.G. and Sung, T., 'A Quantitative Study on Important Factors of the PSA of Safety-Critical Digital Systems,' Journal of KNS, Vol. 33, No.6, (2001)
  10. Min, K.R. et aI., 'Reliability Study: KSNPP Reactor Protection System, KAERI/TR-2164/2002, Korea Atomic Energy Research Institute, (2002)