Thermal and Hydraulic Calculations of Accidents at SUNPP Unit 1 Using ATHLET Code

Period: October-December 2001

Customer: GRS (Germany)

The project’s objective was to support the GRS expert group, which took part in checking the SUNPP Unit 1 PSA material, in assessing validity of the accepted initial success criteria. The work included modeling of a selected accident scenario using ATHLET code and comparison of the obtained results with the results of the corresponding calculations performed by RELAP5 code during SUNPP Unit 1 PSA. Based on the comparison, the conclusions regarding validity of the accepted initial criteria for an accident scenario under consideration were formulated.

Within the framework of the project:

  • significant technical differences between SUNPP Unit 1 and series WWER-1000/ V-320 were established (data on Balakovo NPP Unit 4 were taken as basic ones);
  • existing four-loop model of a power unit with WWER-1000 was adapted for ATHLET code in order to perform calculations for SUNPP Unit 1;
  • test calculations to adjust the developed model were performed;
  • calculations (including alternative ones) of an accident scenario selected from SUNPP Unit 1 PSA were performed.

Results of the project are presented in ‘Identification of Major Technical Differences in a Design of WWER-1000 Models V302 and V320. Calculations of LOCA with a Diameter of 50 mm for SUNPP Unit 1 (Final Report)’. Based on the work results, the conclusions on a validity of success criteria for a selected accident scenario were formulated, as well as the comments and recommendations to the PSA developers.

Director of Safety Analysis Laboratory
Oleg I. Zhabin
Tel./Fax +38 (044) 559 66 07

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