Research at The University of Manchester suggests that the preferred candidate fuel to replace uranium oxide in nuclear reactors may need further development before use.

Dr Robert Harrison led the research, published in the journal Corrosion Science, with colleagues from the University and the Dalton Nuclear Institute.

“Since the 2011 Fukushima accident,” explains Dr Harrison, “there has been an international effort to develop accident tolerant fuels (ATFs), which are uranium-based fuel materials that could better withstand the accident scenario than the current fuel assemblies.”

One of these ATFs is a uranium silicon compound, U­­­­ 3 Si 2 . This material conducts heat much better than the traditional uranium oxide fuels, allowing the reactor core to be operated at lower temperatures. In an emergency situation, this buys more time for engineers to bring the reactor under control.

However, there are many unknowns about how U­­­­ 3 Si 2 will behave in the reactor core. “One of these unknowns,” says Dr Harrison, “is how it will behave when exposed to high temperature steam or air, as may happen during manufacturing or a severe accident during reactor operation.”

To investigate just how accident tolerant ATFs are, Dr Harrison and his colleagues investigated how Ce 3 Si 2 – a non-radioactive material analogous to U­­­­ 3 Si 2 – behaved under exposure to high-temperature air.