In this paper we have analyzed accounting spent nuclear fuel (SNF) burnup of VVER-1000 and RBMK-1000 only with actinides.
The following characteristics were analyzed: initial fuel enrichment, burnup fraction, axial burnup profile in the fuel assembly (FA) and fuel weight.
As the results show, in the first 400 hours after stopping the reactor, there is an increase in the effective neutron multiplication factor (keff) due to beta decay of 239Np into 239Pu. Further, from 5 to 50 years, decrease in keff due to beta decay of 241Pu into 241Am. In the future there is a slight change in criticality of the system.
Accounting nuclear fuel burnup in the justification of nuclear safety of SNF storages will provide an opportunity to increase the volume of loaded fuel and thus significantly reduce technology costs of handling of SNF.