Prospects of using different clad materials in a material test research reactor - Part 1 - The kinetic parameters

The kinetic parameters of a material test research reactor using stainless steel-316 and zircaloy-4 as clad were calculated. For this purpose, the aluminum clad of an MTR was replaced separately with stainless steel-316 and zircaloy-4. Calculations were carried out to find the core excess reactivity, neutron flux spectrum, prompt neutron generation time and effective delayed-neutron fraction. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It was observed that at the beginning of life, the excess reactivity was maximum at 0.054110 Δk/k when zircaloy-4 was used as clad while it was minimum at −0.365650 Δk/k when stainless steel-316 was the clad as compared to 0.017945 Δk/k for aluminum. The thermal neutron flux at the mid of the central flux trap increased by 59.9% and 12.5% for stainless steel and zircaloy-4 clads, respectively, from the flux of the original aluminum clad. The prompt neutron generation time was maximum at 45.36 μs when stainless steel-316 was the clad while it was minimum at 44.03 μs for the original aluminum clad. The effective delayed-neutron fraction was maximum at 0.007185 for the original aluminum clad while it was minimum at 0.007078 for stainless steel clad.