薄壁环形UO_(2)芯块烧结变形研究

Research on Sintering Deformation of the Ring UO_(2) Pellets

采用UO_(2)粉末制备的薄壁环形生坯芯块具有较大的烧结变形,在模具设计时需考虑变形对磨削余量和倒角宽度的影响。环形芯块烧结变形程度会影响芯块外径和倒角宽度,要使薄壁环形芯块满足外径磨削要求(13.63±0.012)mm,阴模直径需从现有的16.70mm提高到16.80mm,冲头倒角宽度需从现有的0.72mm提高到0.86mm。在内径免磨削情况下,环形芯块的严重烧结变形会对内层包壳设计产生影响;内层包壳的外径设计尺寸要比芯块内径目标值至少小0.311mm,才能既保证芯块及时传热,又避免芯块和内包壳之间产生严重的机械相互作用。

The ring UO_(2) pellets mading by IDR have a big sintering deformation,the influence for grinding allowance and chamfer width should be considered in die design.In order to meet the technical requirements(13.63±0.012 mm)as much as possible,the diameter of die must elevate from 16.70 mm to 16.80 mm,the chamfer width of the punch must elevate from 0.72 mm to 0.85 mm.Because of no grinding for the inner diameter,the severe deformation have an impact on the inner cladding design.To ensure the heat diffusion soon and avoid the interaction between UO_(2) pellet and inner cladding,the outer dimeter of the inner cladding is at least 0.311 mm smaller than the inner diameter of the ring UO_(2) pellet.