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三结构同向性型(Tristructural isotropic,TRISO)包覆燃料颗粒是目前高温气冷堆和固态燃料熔盐堆采用的燃料元件。TRISO包覆燃料颗粒破损会导致裂变产物不可接受的释放,由此影响反应堆的安全运行。基于TRISO包覆燃料颗粒压力壳式破损模型,分析了TRISO包覆燃料颗粒核芯和各包覆层的尺寸对失效概率的影响,研究了TRISO包覆燃料颗粒核芯半径、疏松热解碳(Buffer)层厚度和碳化硅(Si C)层厚度的合理设计范围。同时,利用随机抽样统计的方法分析了TRISO包覆燃料颗粒核芯半径分布和各包覆层厚度分布对颗粒失效概率的影响。研究发现,降低Buffer层厚度分布的标准差至16μm可以使TRISO包覆燃料颗粒的失效概率降低一个数量级。
Tristructural isotropic (TRISO) coated fuel particles are the fuel elements used in high temperature gas cooled reactors and solid fuel molten salt reactors. TRISO coated fuel particle damage can lead to unacceptable release of fissile products, thereby affecting the safe operation of the reactor. Based on TRISO coated fuel particle pressure shell damage model, the influence of the size of TRISO coated fuel particle core and each coating on the failure probability was analyzed. The effects of TRISO coated fuel particle core radius, loose pyrolytic carbon Buffer layer thickness and silicon carbide (Si C) layer thickness of the reasonable design range. At the same time, the random sampling method was used to analyze the influence of the distribution of TRISO coated fuel core radius and the thickness distribution of coating on the probability of particle failure. The study found that reducing the standard deviation of the thickness distribution of the buffer layer to 16 μm can reduce the probability of failure of TRISO-coated fuel particles by an order of magnitude.