GREENCDT Proving the process of spent fuel drying

This project supports the future stewardship for spent AGR fuel. The NDA strategy is to consolidate all spent AGR fuel in a single pond at the THORP facility at the Sellafield site for interim storage, pending a future decision on their disposition route. Whilst the primary plan is for long term wet storage, should issues arise it is recognised that fuel may need to be dried and dry stored.

Leeds have been leading academic research in the UK into the drying of SNF, starting in 2013 a series of three PhD projects have been run investigating drying of AGR and Magnox fuels. So far, investigations proven drying conditions and looked at whether water can be removed through cracks in the cladding. This project is intended to build upon work carried out in earlier PhD’s carried out by Leeds and to make use of data use collected as part of other NDA funded projects.

The aim of this project will be to bridge this gap by developing a full sized mock fuel pin which can potentially be manufactured in bulk for use in future drying trials.

The project will create a “pin” that was suitable for large scale drying experiments. The key aspects would be to develop something that behaved in a suitable manner i.e. it does not have to be a perfect replica it just has to have the right characteristics. For example, we can’t reliably crack 20/25 but we can crack 304 so can we could use that. Other aspects that will be important are:

• defect permeability.
• matching thermal properties and behaviour;
• surrogate fuel pellets;
• replicating decay heat;
• cladding condition other than cracking, e.g. carbon deposits