Intrinsically secure fast reactors for long-lived waste free and proliferation resistant nuclear power

This paper provides description of a nuclear reactor concept aimed towards a radical safety enhancement, an increased proliferation resistance, as well as a realisation of a “long-lived waste free” NP development. It emphasizes the achievement of considerable reduction (“by design”) of residual actinides in the waste streams and of the most hazardous long-lived fission products. It allows to implement only small volume of repositories for the radioactive waste (mostly fission products) and to postpone the technically arduous problems of a large scale disposal of the long-lived wastes until the next millennium, i.e. up to the exhaustion of the fertile natural resources and/or the emergence of more effective technologies of nuclide separation/transmutation.A thorough incineration/transmutation of the wastes (residual actinides in the mixture with lanthanides as well as of the most hazardous fission products) under reactor neutron flux is proposed for their mass reduction. A gradual growth of NP park is necessary for increasing the NP park capacity for waste irradiation. This “constraint” is not really limiting because it coincides with the permanently growing demands in energy production. The potential of long-lived waste reduction depends on the total fertile fuel resources and on NP growth rate. It was shown that the accumulated actinide long-lived radioactive masses will be reduced significantly: by factor in the range of 104–108 in magnitude (compared with LWR once-through cycle) and by 102–106 (compared with the ordinary fast reactor park). Thus, the total long-lived waste toxicity pollution source might be comparable with the “burnt away” toxicity of the natural fertile feed stream. This is quite realistic taking into account the large fertile fuel (U/Th) world-wide resources which provide the NP growth for a sustained time. Along side with the radical intrinsic safety improvement, a further enhancement of core physics (“neutronics”) is one of the decisive factors when long-lived waste radical reduction is an objective.For considerable amelioration of neutronics, the hard neutron spectrum of the “dense cores” with elevated neutron production per fission is strongly recommended. Respecting nuclear physics, reactors with such cores (ISFR) of the modular and monolithic configurations can be considered as real candidates for prospective long-lived waste free NP with both the radically enhanced safety potential and the reduced proliferation risks.