Study on the LWR spent fuel management with hybrid fusion-fission reactors

The reactor studied in this work is the hybrid fusion-fission transmutation system (FFTS). It uses a high energy neutron source produced with deuterium-tritium fusion reactions, which is located in the center of the system, and is surrounded by a region composed of fuel where the fission reactions take place. This fuel can be obtained from the recycling of LWR spent fuel. In this paper the MCNPX Monte Carlo code was used to setup a model of the FFTS. Two fuel types were analyzed: the mixed oxide fuel MOX, and the inert matrix fuel. IMF. Results show that in the case of the MOX fuel, an important Pu-239 breeding is achieved, which can be interesting from the point of view of uranium utilization. On the contrary, in the case of the IMF fuel, high consumption Pu-239 and Pu-241 is observed, which can be interesting from the point of view of non-proliferation issues. A combination of MOX and IMF fuels was also studied, which shows that equilibrium of actinides production and consumption can be achieved. These results demonstrate the versatility of the hybrid fusion-fission systems for LWR spent fuel transmutation