DOI QR코드

DOI QR Code

Study on multi-unit level 3 PSA to understand a characteristics of risk in a multi-unit context

  • Received : 2019.08.12
  • Accepted : 2019.11.04
  • Published : 2020.05.25

Abstract

Since the Fukushima Daiichi accident in 2011, concerns for the safety of multi-unit Nuclear Power Plant (NPP) sites have risen. This is because more than 70% of NPP sites are multi-unit sites that have two or more NPP units and a multi-unit accident occurred for the first time. After this accident, Probability Safety Assessment (PSA) has been considered in many countries as one of the tools to quantitatively assess the safety for multi-unit NPP sites. One of the biggest concerns for a multi-unit accident such as Fukushima is that the consequences (health and economic) will be significantly higher than in the case of a single-unit accident. However, many studies on multi-unit PSA have focused on Level 1 & 2 PSA, and there are many challenges in terms of public acceptance due to various speculations without an engineering background. In this study, two kinds of multi-unit Level 3 PSA for multi-unit site have been carried out. The first case was the estimation of multi-unit risk with conservative assumptions to investigate the margin between multi-unit risk and QHO, and the other was to identify the effect of time delays in releases between NPP units on the same site. Through these two kinds of assessments, we aimed at investigating the level of multi-unit risk and understanding the characteristics of risk in a multiunit context.

References

  1. Dong-San Kim, et al., Multi-unit Level 1 probabilistic safety assessment: approaches and their application to a six-unit nuclear power plant site, Nucl. Eng. Technol. 50 (2018).
  2. Jaehyun Cho, Sang Hoon Han, Dong-San Kim, Ho-Gon Lim, Multi-unit Level 2 probabilistic safety assessment: approaches and their application to a six-unit nuclear power plant site, Nucl. Eng. Technol. 50 (2018).
  3. Sung-yeop Kim, et al., Multi-unit Level 3 probabilistic safety assessment: approaches and their application to a six-unit nuclear power plant site, Nucl. Eng. Technol. 50 (2018).
  4. Ho-Jun Jeon, Kyemin Oh, Ki-In Bahng, Evaluation Plan for Multi-Unit PSA Considering Operating Modes in a Reference Site, Transactions of the Korean Nuclear Society Spring Meeting, 2017.
  5. Ho-Jun Jeon, Kyemin Oh, Jeongseon Park, Preliminary Modelling Approach for Multi-Unit PSA in Korea [Utility Side], OECD/NEA International Workshop on Status of Site Level PSA Development, 2018.
  6. Kyemin Oh, Ho-Jun Jeon, Jeongseon Park, Modelling approaches in KHNP multi-unit PSA project, in: Transactions of the Korean Nuclear Society Autumn Meeting, 2018.
  7. D. Chanin, M.L. Young, J. Randall, K. Jamali, Code Manual for MACCS2, User's Guide, NUREG/CR-6613, U.S. NRC, Washington D.C., 1998, p. 1. SAND97-0594.
  8. IAEA, Arrangements for Preparedness for a Nuclear or Radiological Emergency, IAEA Safety Standards Series GS-G-2.1, 2007.
  9. EPRI, PSA Applications Guide, EPRI TR-105396, 1995.
  10. KHNP CRI, Evacuation Time Estimates, 2014.
  11. U.S. NRC, Safety Goals for the Operation of Nuclear Power Plants, 1986.