Structural integrity evaluation of irradiated LEU targets for the production of molybdenum‑99 using thermo‑mechanical behavior simulation coupled with pressure of fission gas release calculation  

作　　者：N.Mellel B.Mohammedi M.Salhi M.Dougdag S.Missaoui S.Hanini 

机构地区：[1]Birine Nuclear Research Center,PB 180,17200 Ain Oussera,Djelfa,Algeria [2]LBMPT UniversitéDr Yahia Farès,26000 Médéa,Algeria

出　　处：《Nuclear Science and Techniques》2022年第12期12-23,共12页核技术（英文）

摘　　要：Irradiated low-enriched uranium as target plates is used to produce,via neutron radiation and from the molybdenum-99 fission product,technetium-99m,which is a radio-element widely used for diagnosis in the field of nuclear medicine.The behavior of this type of target must be known to prevent eventual failures during radiation.The present study aims to assess,via prediction,the thermal–mechanical behavior,physical integrity,and geometric stability of targets under neutron radiation in a nuclear reactor.For this purpose,a numerical simulation using a three-dimensional finite element analysis model was performed to determine the thermal expansion and stress distribution in the target cladding.The neutronic calculation results,target material properties,and cooling parameters of the KAERI research group were used as inputs in our developed model.Thermally induced stress and deflection on the target were calculated using Ansys-Fluent codes,and the temperature profiles,as inputs of this calculation,were obtained from a CFD thermal–hydraulic model.The stress generated,induced by the pressure of fission gas release at the interface of the cladding target,was also estimated using the Redlich–Kwong equation of state.The results obtained using the bonded and unbonded target models considering the effect of the radiation heat combined with a fission gas release rate of approximately 3%show that the predicted thermal stress and deflection values satisfy the structural performance requirement and safety design.It can be presumed that the integrity of the target cladding is maintained under these conditions.

关 键 词：Irradiated LEU target Mo-99 production Integrity evaluation Thermo-mechanical analyses Fission gas pressure 

分 类 号：TL92[核科学技术—核燃料循环与材料]