Application of Burnup Credit Methodology on WWER-440 Reactors Spent Fuel Pool Re-Racking Analysis

Transition of ANPP to the fuel assemblies with higher  enrichment  (3.82%)  and  consequently,  higher burnup,  could  cause  shortage  of  free  cells  in  the  spent fuel pool due to doubling of the pre-cooling time of the spent fuel assemblies in the spent fuel pools to meet ANPP NUHOMS type dry spent fuel storage  acceptance  criteria.  One  of  the  possible options  to  overcome  shortage  of  free  cells  could be compacting (re-racking) of spent fuel pools, applying  burnup  credit  approach.  Bounding  isotopic composition of
WWER-440 spent fuel was calculated by using ORIGEN-S program of SCALE 6.1 package. Developed model of WWER-440 fuel assembly was verified and validated against WWER-440 reactor fuel chemical assay data. Criticality  safety  analysis  of  spent  fuel  pool  was  carried  out  by  applying  Actinides-only  option  of  burnup  credit  approach.  Model  of  WWER-440  reactor  spent  fuel  pool was  developed  by  MCNP6.1  code.