NEA (2024), Status Report on Fuel Safety Implications of Extended Enrichment and High Reactivity/High Suppression Core Designs: A Report from the Working Group on Fuel Safety (WGFS), OECD Publishing, Paris
Rising international interest in increasing fuel burnup limits and fuel cycle length may require fuel enrichment above 5% and high reactivity/high suppression core designs. Based on this interest in extended fuel enrichment (5-8%), the Nuclear Energy Agency (NEA) Working Group on Fuel Safety (WGFS): 1) collected information on fuel enrichment limits for uranium dioxide fuel in light water reactors in NEA member countries through a questionnaire; 2) consolidated the information in a status report 3) utilised WGFS expertise to evaluate fuel safety implications of extended enrichment fuel and high reactivity/high suppression core designs; and 4) provided recommendations for collaborative analytical and experimental research on this topic. The task group focused on in-reactor behaviour of high reactivity/high suppression core designs. Issues related to the front-end (e.g. fuel fabrication) and back-end (e.g. spent fuel storage) of the fuel cycle are outside the scope of this report.
The questionnaire responses indicated that while there is limited operating experience in NEA member countries with fuel enrichment of 5-8%, extensive experimental data from research and test reactors could be used to validate neutronic and fuel performance codes and methods for extended enrichment fuel. From these responses, the group concluded that there are no major experimental gaps related to extended enrichment fuel behaviour.