Study On HPR1000 Hybrid Core Loading Scheme With MOX Fuel And Analysis Of Control Poison

MOX fuel is a widely used nuclear fuel in the world.The fuel is processed from plutonium isotopes and depleted uranium,which can greatly improve the utilization of Pressurized Water Reactor fuel and effectively recover weapons-grade plutonium.The use of MOX fuel can increase the utilization rate of Pressurized Water Reactor nuclear fuel,decrease the reserve of spent fuel,and improvement of domestic fuel cycle industrial chain,and improve the efficiency of the economy,which are of great significance to the development of China's nuclear power industry.Therefore,in this paper,the third-generation domestic Pressurized Water Reactor HPR1000 is taken as the research object,and proposed a set of core fuel position arrangement scheme that can be combined with core space search.The scheme mainly includes the following section:(1)Establishing reliable core modeling of HPR1000 reactor using MCNP5,ORIGEN2.1,MATLAB and other software.(2)The MOX fuel assembly and the hybrid core loading scheme for the MOX fuel assembly were studied and designed,which based on the core modeling.(3)The hybrid core model was used to study the change of the temperature coefficient of the moderator when the boron concentration was changed in the moderator and the influence on the reactivity of the hybrid core.The degree of boron enrichment would be appropriate for the hybrid core was found.(4)By analyzing the characteristics of MOX fuels and UO2 fuels,burnable poisons suitable for hybrid cores are researched and designing burnable poison appropriate arrangements are designed.(5)To find the control rod poison suitable for the hybrid core designed in this paper,and to analyze the poison of the control rod to the core control reactivity.By the aforementioned work,a set of hybrid core adjustment scheme that is more appropriate for MOX fuel.First,the hybrid core loading scheme can better reduce the power gradient among components and flatten the power distribution of the core.Secondly,the moderator that boron enrichment degree about 40% can better control thecore reactivity under the premise of ensuring the safety of the reactor core.Again,the burnable poison of Er2O3 can flatten the power in the fuel assembly through the IBAS designed in this paper,and the rational arrangement of IBAS assembly can achieve the purpose of flattening the core neutron flux distribution and power distribution while controlling the reactor core reactivity.Finally,the control rods using Dy2O3-Ti O2 and Hf B2 as materials can be effectively controlled reactor core reactivity.The adjustment scheme can better to adjust the power distribution and reactivity control of the hybrid core,and the core space search can achieve the optimal arrangement of the core,and can provide certain references and ideas about the core adjustment for the introduction of MOX fuel in China's PWR in the future.