The study of the self-catalytic criticality phenomenon of fissile materials in spent nuclear fuel disposal in geological formations in the European North of Russia

Using methods of nuclear reactors physics the phenomenon of potential cnticality has been studied within the framework of the concept of geologic repository of the non-processible spent nuclear fuel of the ship nuclear power installations. For the fractured rock mathematical model the minimum thickness of fissile material (UO2) on cracks' surface conforming to critical masses of heterogenous deposits have been determined. The scenario of autocatalytic criticality originated by change of a climate and developed at the expense of heating of medium, and water-transport from pores and cracks of rock has been described. The conclusion about preferability of the concept of termporary storage of non-processible spent nuclear fuel has been made.