Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
Dispersed pellet fuels and plate fuel elements in new pressurized water reactors have good prospects for application. Dispersed fuel has the advantages of extremely infusible character, strong fission product retention, high oxidation resistance, and mainly exists in the form of pellets. Meanwhile, reactivity is a crucial issue during the operation of the reactor, which needs to be well controlled throughout its life cycle, and the implementation of burnable poison is one of the most effective measures. Therefore, in this paper, based on the Monte Carlo method program OpenMC, a two-dimensional plate fuel grid element is constructed with a single plate in the MTR assembly as the study object , and the dispersed particles are set up and then the volume is homogenized. As a comparison, both two methods have the same material with the same mass, and the conventional volume homogenization method will overestimate the neutron absorption effect, which will lead to a large deviation in the reactivity calculation. At the same time for different setting conditions deviation is different, with the increase of enrichment, particle size increases, packing factor decreases its deviation will gradually increase; the increase of the temperature of the moderator affects the temperature coefficient of the moderator and thus makes the reactivity deviation change but the trend is not obvious, at the same time the dispersed particles with poison will also cause deviation, and different poison affects differently.
