Burnup estimation for plate type fuel assembly of research reactors through the least square fitting method

• A least square fitting approach is proposed to estimate the fuel burnup for the plate type fuel assembly of research reactors.
• Linear and nonlinear fitting methods are derived by using parameters such as power density, enrichment and fuel density.
• Three different cores with U3Si2 and UMo fuels are taken into consideration for application of the proposed method.

This work is focused on estimation of burnup for a plate type fuel assembly of research reactors with the SCALE6 code sequences such as TRITON/NEWT and ORIGEN-ARP. And a simple and accurate model is proposed to calculate burnup based on the least square fitting method without additional depletion analyses. One fuel assembly is modeled and its burnup is obtained for different power densities, enrichments, and fuel densities. Linear and non-linear polynomial fitting methods are used to provide a suitable formula for the burnup of the plate type fuel assembly with a function of different parameters. And the proposed approach is applied to three configurations of research reactors, such as a 5 MW core of U3Si2 fuel, 3 MW cores with U3Si2 and UMo fuels. The results are also validated by comparing those of Monte Carlo codes.