Compositional and Structural Evolution of Plutonium Dioxide: Underpinning Future Decisions

Completed

Nuclear Fission and Fusion(Nuclear Fission, Nuclear supporting technologies)

Basic and strategic applied research

PHYSICAL SCIENCES AND MATHEMATICS (Physics)

Not Cross-cutting

Professor JFW Mosselmans
Science Division
Diamond Light Source Ltd

Standard

EPSRC

01 June 2020

20 November 2023

42 months

£13,785

Energy

South East

Energy : Energy

Professor JFW Mosselmans, Science Division, Diamond Light Source Ltd

Plutonium dioxide is a very dynamic material. Radioactive decay damages the lattice and also forms other elements in the material. Helium, an inert gas, may be localised or trapped in the lattice, or maybe released. Uranium isotopes (formed from the decay of plutonium-238, 239, 240) and americium-241 (formed from decay of plutonium-241) are formed atom-by-atom within the plutonium dioxide lattice. The UK has 140 tonnes of separated plutonium in the form of plutonium dioxide, the World's largest civil stockpile. This has been separated over the last half century and will need to be stored for several decades into the future before its end use. Currently, Government intends most of this material to be made into nuclear reactor fuel ('mixed oxide fuel'), with a small proportion, which cannot be made into fuel, being disposed of as waste, although policy changes could lead to more of it being designated as waste. Whatever the final fate of the plutonium, the material will need to be processed into a suitable form for its end use, and its evolution while it is being stored will affect its suitability for processing. We therefore need to be able to predict how plutonium dioxide will change in storage, so we know whether it will be suitable for its final use. The purpose of this project is to understand how plutonium dioxide changes so we can make these predictions.

06/08/25