VVER-440 Spent Fuel Pool Calculations with the MAAP5-VVER Code

Severe accident analyses for the spent fuel pool of the VVER-440/213 plant have been performed with the MAAP5-VVER code. The selected sequence was an unmitigated loss-of-cooling accident. MAAP5 modelling of the SFP is quite advanced due to several features including the possibility of modelling rectangular pool geometries. The SFP input deck for the MAAP5 code has been set up using plant specific data concerning SFP dimensions, parameters and materials. Accident progression has been analyzed by tracking thermal-hydraulic parameters and fission product release during the sequence. Results of the calculations have been found physically reasonable. Additional check of the results has been performed via code-to code comparison with a similar MELCOR analysis. Computer run times of MAAP5-VVER for a typical SFP transient lasting 200 h have been less than 20 min on a usual PC under Microsoft Windows. Graphical capabilities of the code are flexible and efficient enabling the analyst to review and study physical parameters. (author)