An Approach to Estimation of Radiological Source Term for a Severe Nuclear Accident using MELCOR code

MELCOR 코드를 이용한 원자력발전소 중대사고 방사선원항 평가 방법

  • Published : 2012.12.31


For a severe accident of nuclear power plant, an approach to estimation of the radiological source term using a severe accident code(MELCOR) has been proposed. Although the MELCOR code has a capability to estimate the radiological source term, it has been hardly utilized for the radiological consequence analysis mainly due to a lack of understanding on the relevant function employed in MELCOR and severe accident phenomena. In order to estimate the severe accident source term to be linked with the radiological consequence analysis, this study proposes 4-step procedure: (1) selection of plant condition leading to a severe accident(i.e., accident sequence), (2) analysis of the relevant severe accident code, (3) investigation of the code analysis results and post-processing, and (4) generation of radiological source term information for the consequence analysis. The feasibility study of the present approach to an early containment failure sequence caused by a fast station blackout(SBO) of a reference plant (OPR-1000), showed that while the MELCOR code has an integrated capability for severe accident and source term analysis, it has a large degree of uncertainty in quantifying the radiological source term. Key insights obtained from the present study were: (1) key parameters employed in a typical code for the consequence analysis(i.e., MACCS) could be generated by MELCOR code; (2) the MELOCR code simulation for an assessment of the selected accident sequence has a large degree of uncertainty in determining the accident scenario and severe accident phenomena; and (3) the generation of source term information for the consequence analysis relies on an expert opinion in both areas of severe accident analysis and consequence analysis. Nevertheless, the MELCOR code had a great advantage in estimating the radiological source term such as reflection of the current state of art in the area of severe accident and radiological source term.


nuclear power plant;severe accident;radiological source term;consequence analysis;MELCOR


  1. Kim, D. et al, "Comparison of MELCOR and MAAP Calculation Results in Evaluating Risk of Early Fatality for OPR-1000 Plant,"Transaction of the Korean Nuclear Society Autumn Meeting, Gyeongju, Korea, October 29-30, 2009
  2. U.S.NRC, "State-of-the-Art Reactor Consequence Analysis (SOARCA) Report,"Draft, NUREG-1935, 2012
  3., 웹사이트 참조
  4. 안광일 외, " 표준원전 OPR1000 Level 2 리스크 최적 평가 모델 PRiME-L2 개발," KAERI/ TR-4665, 2012
  5. 한국전력기술주식회사, "한국표준형원전의 AOT/ STI 요건 완화 기술개발," 산업자원부, 2004
  6. 정건효 외, "MELCOR 코드기반 OPR1000 Level 2 조기격납건물 손상 사고경위 모델에 대한 현상학적 불확실성 평가,"KAERI/TR-4348, 2011
  7. Ahn, K. et al, "The Plant-Specific Uncertainty Analysis for an Ex-Vessel Steam Explosion-Induced Pressure Load Using a TEXAS-SAUNA Coupled System," Nuclear Engineering and Design, Vol. 249, pp. 400-412, 2012
  8. 조성원, MELCOR 코드에 관한 기술 자문, 2012
  9. Pilch, M.M. et al, "Resolution of the Direct Containment Heating Issue for All Westinghouse Plants with Large Dry Containments or Subatmospheric containments," NUREG/CR-6338, Sandia National Laboratories, U.S. NRC, 1996
  10. 한국원자력학회 후쿠시마위원회, " 후쿠시마 원전 사고 분석 (축약본)-초안,"한국원자력학회, 2012
  11. U.S.NRC, "Accident Source Term for Light-Water Nuclear Power Plants,"NUREG-1465, 1995
  12. U.S.NRC, "Technical Guidance for Siting-Criteria Development," NUREG/CR-2239, 1982
  13. U.S.NRC, "Source Term Estimation During Incident Response to Severe Nuclear Power Plant Accidents," NUREG-1228, 1988
  14. Haste, T. et al, "MELCOR/MACCS Simulation of the TMI-2 Severe Accident and Initial Recovery Phases, Off-site Fission Product Release and Consequences," Nuclear Engineering and Design, Vol. 26, pp. 1099-1112, 2006
  15. Electric Power Research Institute (EPRI), "MAAP4, Modular Accident Analysis Program User' Manual," EPRI Report prepared by Fauske & Associates, Inc., 1994
  16. Gauntt, R.O. et al, "MELCOR Computer Code Manuals, Vol. 1: Primer and Users' Guide, Version 1.8.6," NUREG/CR-6119, Vol. 1., Rev. 3, Sandia National Laboratories, 2005
  17. D.I. Chanin and M.L. Young, "Code Manual for MACCS2: Volume 1, User' Guide,"NUREG/CR-6632, Sandia National Laboratory, US NRC. 1998
  18. McFadden, K., "MELMACCS Model Documents," in MELMACCS Install Program, 2011


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