<p>Disposal of long-lived and highly toxic nuclides such as minor actinides (MA) is an important issue for nuclear applications. To reduce the amount of MA, Partitioning and Transmutation has been proposed, and several transmutation systems such as a fast reactor, an accelerator-driven system, and a fusion reactor have been studied. Our previous study has performed a burnup simulation of MA loaded in a fusion reactor blanket, whose result has indicated that the large amount of MA was changed to even-numbered isotopes of plutonium, particularly Pu-238, by rather moderate transmutation in a thermal neutron field. The nuclide Pu-238 has a large neutron capture cross section, and it becomes fissile Pu-239 by the reaction. When the plutonium transmuted from MA is loaded into light water reactor (LWR) appropriately, there is a possibility to maintain a constant effective multiplication factor in LWR. This is because the plutonium suppress the initial excess reactivity by the neutron capture reaction, and subsequently the plutonium becomes the fissile Pu-239 leading to increase the reactivity. Furthermore, reutilization of the plutonium transmuted from MA contributes to reduce the use of fresh U-238 in LWR, which results in the decrease of MA production. Based on these backgrounds, we propose to make effective use of the plutonium transmuted from MA by fusion reactors as fertile fuel &nbsp;in LWR for an improvement of the existing nuclear fuel cycle. This study evaluated the effects of the plutonium transmuted from MA on the effective multiplication factor and power distribution of a full MOX boiled water reactor (BWR) core. Monte Carlo neutron transport simulation using MVP-2.0 with JENDL-4.0 data library was performed to evaluate the effect of the loading position and amount of plutonium transmuted from MA. We also performed burnup analysis to evaluate the variation of transuranic (TRU) isotopic composition. We revealed that some fuel assemblies achieved the effective multiplication factor is greater than 1.0 and its deviation was significantly small (±0.01) during 400 days operation. These results indicate that the plutonium transmuted from MA by fusion reactors effectively suppresses the initial excess reactivity and gradually raises the reactivity by becoming the fissile Pu-239 in BWR.</p>

Evaluation of the Applicability of Plutonium Transmuted From Minor Actinides by Fusion Reactor as Fertile Fuel in Boiling Water Reactor

Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE28/volume/85246

2021 28th International Conference on Nuclear Engineering (ICONE28)

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