Assessment of sensitivity of neutron-physical parameters of fast neutron reactor to purification of reprocessed fuel fro
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ssment of Sensitivity of NeutronPhysical Parameters of Fast Neutron Reactor to Purification of Reprocessed Fuel from Minor Actinides V. A. Chernya, L. A. Kochetkova, and A. I. Nevinitsab a
Obninsk Institute for Physics and Power Engineering, pl. Bondarenko 1, Obninsk, Kaluga oblast, 249033 Russia b Institute of Nuclear Power Engineering, National Research Nuclear University MEPhI, Studgorodok 1, Obninsk, Kaluga oblast, 249040 Russia email: [email protected] Received March 7, 2012
Abstract—The work is devoted to computational investigation of the dependence of basic physical parame ters of fast neutron reactors on the degree of purification of plutonium from minor actinides obtained as a result of pyroelectrochemical reprocessing of spent nuclear fuel and used for manufacturing MOX fuel to be reloaded into the reactors mentioned. The investigations have shown that, in order to preserve such important parameters of a BN800 type reactor as the criticality, the sodium void reactivity effect, the Doppler effect, and the efficiency of safety rods, it is possible to use the reprocessed fuel without separation of minor actinides for refueling (recharging) the core. Keywords: fast reactor, refueling of fuel assemblies, minor actinides, reprocessing. DOI: 10.1134/S1063778813140056
INTRODUCTION The strategy of the Russian Federation in the field of nuclear power is directed to the application of plu tonium in fast reactors and closing of their fuel cycle on plutonium. Such a strategy sets the problem to cre ate industrial reprocessing of nuclear fuel spent in fast reactors and reuse the separated plutonium. One of the determining aspects of the technology used to reprocess the spent nuclear fuel with separa tion of plutonium is the degree of its purification from other elements and, in particular, from minor actinides (MAs) and fission products. It is clear that the degree of plutonium purification, which deter mines its nuclear, radiation, and thermal parameters, affects the conditions of handling during production and transport of the fuel, fuel elements, and fuel assemblies (FAs) on the basis of this plutonium as well as the physical and other characteristics of fast reactors into which these FAs are loaded. A general consideration naturally dictates the aim to obtain the purest plutonium to decidedly reduce the above list of negative effects. However, this quest leads to a complication in the technology of processing the spent nuclear fuel and, finally, to a deterioration of technical and economic characteristics of the process ing plant. It is clear that a compromise is necessary, i.e., searching for an optimally acceptable degree of pluto nium purification in order to provide the required properties of fuel for fast reactors, which will not be a
heavy burden on the production by either the repro cessing of spent nuclear fuel or fabrication of fresh fuel from it. This work is devoted to one of the aspects of the problem under consideration, namely, the computa tional studies of the effect on the basic
