Towards Analysis of the Bowing Effect on Burnt Nuclear Fuel Compositions Using SERPENT

Nuclear fuel research has some specificities mainly due to the high irradiation environment in the reactor core. Fuel materials under high irradiation undergo unique behaviors such as growth and creep, which can result in bowing of fuel rods [1]. The fuel rod bow can lead to the contact of neighboring rods and shrink water regions between them. As a consequence, local changes on water moderation in Light Water Reactors (LWR) might affect the isotopic concentrations and their distributions with burn-up. However, in most computational models, the bowing effect on fuel rods is not taken into account [2]. It is therefore essential to investigate the influence of bowing on nuclear computations in general and on assembly depletion in particular. The latter is the topic of primary interest in this paper. This paper investigates the relative difference of isotopic concentrations induced by bowing to provide a qualitative overview of the effect of bowing via moderation on depletion and build-up of isotopes through burn-up in the fuel rod. Moreover, it illustrates relative isotopic concentrations differences in the perspective of evaluating biases between computational simulation results and the experimentally measured results.