Neutron-Physical Aspects of the Conceptual Validation of a Fast Reactor with an Open Fuel Cycle

This article is devoted to the pressing issue of achieving fuel security by realizing in fast reactors the best breeding of new fissile materials from the initial isotopes and using the accumulated fissile isotopes in the same reactor irrespective of the rates at which the spent nuclear fuel is reprocessed in the external fuel cycle. Two fast-reactor concepts based on the same principle are validated by computational means. In the first one, the fissile isotope is replenished with the breeding isotope by moving the neutron flux or energy release along the initially formed composition, consisting of a seed zone and a breeding zone (traveling wave of fission concept); in the second one, the motion of the neutron flux is replaced by the movement of the fuel composition, comprised of fissile and breeding materials (standing wave of fission concept).