Physics-based modelling of fission gas swelling and release in UO2 applied to integral fuel rod analysis

Asymptotic expansion homogenization for multiscale nuclear fuel analysis

“…(25), and the four solution vectors in v computed from Eq. (24). The results are compared to data from other computations given in [4] that are considered in that reference to be trusted solutions.…”

“…The fractional coverages for the six MARMOT simulations are taken from a separate calculation in BISON in which the fission gas release model [24] calculates the fractional coverage throughout the fuel pellet. For the six locations, the fractional coverages were f c ¼ 0:31, 0.22, 0.13, 0.069, 0.036, and 0.011.…”

BISON Theory Manual The Equations behind Nuclear F

“…The level of complexity of the model is consistent with reasonable computational cost and the uncertainties inherent in engineering-scale fuel analysis. The Sifgrs model draws on and extends the approach described in [27].…”

“…• The process of grain-face bubble coalescence, which leads to a progressive decrease of the bubble number density throughout irradiation, is described using an improved model of White [27,35]. According to this model, the rate of loss of bubbles by coalescence is given by…”

Sensitivity analysis of the fission gas behavior model in BISON.

“…Recently, a new physics-based model of fission gas release and swelling in UO 2 was incorporated in the BISON fuel performance code. The new model is based on the approach described in (10), and practically combines a physical description of the relevant mechanisms with a level of simplicity suitable for the effective application to engineering-scale nuclear fuel analysis. The model incorporates the fundamental features of fission gas behavior, among which are gas generation, diffusion and precipitation in grains, growth and coalescence of gas bubbles at grain faces, grain growth and grain boundary sweeping, thermal, athermal, and transient gas release.…”