Under the guidance of the Nuclear Science Committee, the expert group primarily acted as a forum for scientific and technical information exchange on advanced light water reactor (LWR) fuels with enhanced accident tolerance. The expert group focused on the fundamental properties and behaviour under normal operations and accident conditions for advanced core materials and components (fuels, cladding, control rods, etc.). The materials considered were applicable to Gen II and Gen III Light Water Reactors, as well as Gen III+ reactors under construction.

Objective

The objective of the expert group was to define and co-ordinate a programme of work to help advance the scientific knowledge needed to provide the technical underpinning for the development of advanced LWR fuels with enhanced accident tolerance compared to currently used zircaloy/UO2 fuel systems, as well as other non-fuel core components with important roles in LWR performance under accident conditions.

In particular, the expert group fostered information exchange on material properties and relevant phenomenological experiments, carried out state-of-the-art reviews, organised benchmark studies and fostered international collaborations regarding the development of core materials and designs which provided improved tolerance to accidents. Conditions such as those experienced during the Fukushima incident were considered, but those considerations were not limited to only Fukushima-like events.

Ideally, the new fuel designs provided enhanced tolerance to extended station blackout conditions with loss of active cooling, while maintaining or improving the fuel performance and safety characteristics during normal operations and for other design basis accident (DBA) and beyond design basis accident (BDBA) scenarios.