DOI QR코드

DOI QR Code

APPLICATION OF UNCERTAINTY ANALYSIS TO MAAP4 ANALYSES FOR LEVEL 2 PRA PARAMETER IMPORTANCE DETERMINATION

  • Received : 2013.09.12
  • Accepted : 2013.10.22
  • Published : 2013.11.25

Abstract

MAAP4 is a computer code that can simulate the response of a light water reactor power plant during severe accident sequences, including actions taken as part of accident management. The code quantitatively predicts the evolution of a severe accident starting from full power conditions given a set of system faults and initiating events through events such as core melt, reactor vessel failure, and containment failure. Furthermore, models are included in the code to represent the actions that could mitigate the accident by in-vessel cooling, external cooling of the reactor pressure vessel, or cooling the debris in containment. A key element tied to using a code like MAAP4 is an uncertainty analysis. The purpose of this paper is to present a MAAP4 based analysis to examine the sensitivity of a key parameter, in this case hydrogen production, to a set of model parameters that are related to a Level 2 PRA analysis. The Level 2 analysis examines those sequences that result in core melting and subsequent reactor pressure vessel failure and its impact on the containment. This paper identifies individual contributors and MAAP4 model parameters that statistically influence hydrogen production. Hydrogen generation was chosen because of its direct relationship to oxidation. With greater oxidation, more heat is added to the core region and relocation (core slump) should occur faster. This, in theory, would lead to shorter failure times and subsequent "hotter" debris pool on the containment floor.

Keywords

References

  1. SECY-93-087, "Policy, Technical, and Licensing Issue Pertaining to Evolutionary and Advanced Light Water Reactor (ALWR) Designs" (April 2, 1993).
  2. "MAAP 4 (Modular Accident Analysis Program) User Guidance," Electric Power Research Institute, Volume 1, May 1994.
  3. Uncertainty Working Group of the MAAP User's Group, "Application of Uncertainty Analyses with the MAAP4 Code", available from FAI at http://www.fauske.com/ sites/default/files/ApplicationofUncertaintyAnalyseswitht heMAAP4Code.pdf.
  4. Loeve, M.; Probability Theory, Graduate Texts in Mathematics, copyright in 1977 and the fourth edition published by Springer-Verlag Inc., New York.
  5. Montgomery, Douglas C.; Runger, George C.; Applied Statistics and Probability for Engineers, copyright in 2007 and the fourth edition published by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030-6011.
  6. Tamhane, Ajit C.; Dunlop, Dorothy D.; Statistics and Data Analysis from Elementary to Intermediate, copyright in 2000 and published by Prentice-Hall, Inc., Upper Saddle River, NJ 07458.
  7. S.S. Wilks, "Determination of Sample Sizes for Setting Tolerance Limits," Annals of Mathematical Statistics, Vol. 12, pages 91-96 (1941). https://doi.org/10.1214/aoms/1177731788
  8. Paul N. Somerville, "Tables for Obtaining Non-Parametric Tolerance Limits," Annals of Mathematical Statistics, Vol. 29, Number 2, pages 599-601 (June 1958). https://doi.org/10.1214/aoms/1177706640
  9. "An Acceptable Model and Related Statistical Methods for the Analysis of Fuel Densification," Regulatory Guide 1.126, Revision 2, U.S. Nuclear Regulatory Commission (March 2010).
  10. Kwang-Il Ahn et al., "An Assessment of uncertainty on a LOFT L2-5 LBLOCA PCT based on the ACE-RSM approach: complementary work for the OECD BEMUSE PHASE-III Program," Nuclear Engineering and Technology, Vol. 42, No.2, pp.163-174 (2010). https://doi.org/10.5516/NET.2010.42.2.163
  11. M. Abramowitz and I. Stegun, "Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables," National Bureau of Standards, Applied Mathematics Series 55 (1966).
  12. T. Kollig and A. Keller, "Efficient Multidimensional Sampling," Computer Graphics Forum, Vol. 21, Issue 3: 557-563. doi: 10.1111/1467-8659.00706 (2002).
  13. J. C. Helton, F. J. Davis, and J. D. Johnson, "A comparison of uncertainty and sensitivity analysis results obtained with random and Latin hypercube sampling," Reliability Engineering and System Safety, Vol. 89, pp.305-330, 2005. https://doi.org/10.1016/j.ress.2004.09.006
  14. Uncertainty Working Group of the MAAP User's Group, "MAAP4 Uncertainty and Sensitivity Analyses", available from FAI at http://www.fauske.com/sites/default/files/ MAAP4UncertaintyandSensitivityAnalyses.PDF.
  15. J.C. Helton and F. J. Davis, "Illustration of Sampling- Based Methods for Uncertainty and Sensitivity Analysis," Risk Analysis, Vol. 22, No.3, 2002.
  16. M. D. McKay, R. J. Beckman, and W. J. Conover, "A Comparison of Three Methods for Selecting Values of Input Variables in the Analysis of Output from a Computer Code" (JSTOR Abstract). Technometrics (American Statistical Association), Vol. 21 (2): 239-245. doi:10.2307/1268522. ISSN 0040-1706. JSTOR 1268522. OSTI 5236110 (May 1979).
  17. R. L. Iman, J. C. Helton, and J. E. Campbell, "An approach to sensitivity analysis of computer models: Part I - Introduction, input variable selection and preliminary variable assessment". Journal of Quality Technology, Vol. 13 (3): 174-183 (1981).
  18. R. L. Iman, J. C. Helton, and J. E. Campbell, "An approach to sensitivity analysis of computer models: Part II - Ranking of input variables, Response surface validation, Distribution effect and technique synopsis". Journal of Quality Technology, Vol. 13 (3): 232-240 (1981).
  19. R. L. Iman, J. M. Davenport, and D. K. Zeigler, "Latin hypercube sampling (program user's guide)," OSTI 5571631 (1980).
  20. Sehgal, Bal Raj; Nuclear Safety in Light Water Reactors - Severe Accident Phenomenology, copyright in 2012 and published by Academic Press an imprint of Elsevier, Inc., 225 Wyman Street, Waltham, MA 02451.
  21. EPRI Report 1020236, Revision 2, "MAAP 4 Applications Guidance," July 2010.