Study of the effect of burnup depth on U₃Si₂-Al dispersion helical cruciform fuel

The U₃Si₂-Al dispersed helical cruciform fuel (HCF) element, distinguished by high burnup tolerance and superior thermal conductivity, represents an innovative nuclear fuel design. This study employs finite element analysis (FEA) to investigate the thermo-mechanical behaviors of HCF element under varying U₃Si₂ particle loadings and burnup levels. The results indicate that, at 5 % burnup, increasing the fuel particle volume fraction from 10 % to 30 % raises the maximum fuel temperature from 593.51 K to 598.05 K, while stress concentrates at the concave arc, where the matrix contacts the cladding, reaching a peak stress of 344.95 MPa. At 20 % fuel particle volume fraction under irradiation, burnup progression from 5 % to 20 % increases maximum stress by 46.55 MPa, while temperature distribution remains unaffected. The analysis reveals a transition in stress-dominant factors: at low burnup, the U₃Si₂ particle volume fraction governs stress distribution, whereas at high burnup, irradiation-induced swelling becomes the primary driver of deformation.