Abstract and subjects
Gaseous fission product generation, transport, and release can have a large impact on nuclear fuel performance, degrading fuel and fuel-cladding gap properties. Over the past several decades much progress has been made in understanding the key mechanisms of fission gas behavior through investigations with bulk reactor experiments and simplified analytical models. Concurrently, new mechanisms have come to light that can have a strong influence on gas release, especially the unexpected acceleration of fission gas release under high burn-up conditions. Additionally, novel modeling techniques, such as atomistic, mesoscale, and multiscale methods have joined the arsenal of investigative tools. In this review, existing research on the basic mechanisms of fission gas release during normal reactor operation is summarized, and critical areas where further work is needed are identified and discussed. (C) 2018 Elsevier B.V. All rights reserved.