Characterisation of perforated AGR fuel and its behaviour during drying

A recently completed PhD project tested and proved the feasibility of drying AGR fuels that had been stored for long periods in a caustic environment. The project successfully developed a drying process and proved that end points can be identified.

 

During the project, drying of perforated fuels was simulated in the main using pin holes, but a method to produce characteristic stress corrosion cracks in AGR cladding was used and these samples were used in some drying tests. A joint report to the NDA highlights that perforated cladding may have water ingress into the fuel and should be investigated.

 

This project will build on the previous knowledge by:

• Further development of the preparation methodology to simulate SCC in AGR fuel cladding. Where possible the samples will be compared to “real” cladding so that the characteristic perforations can be validated. Further use of micro-CT scanning will confirm the size and extent of cracking.

• Development of the process to characterise and investigate drying through “cracked cladding”.

• Development of the process to include the effects of “wet” fuel pellets within the cladding. A simulant fuel pellet will be developed that can be inserted into the prepared AGR cladding samples and then the combined test piece will be treated so that is represents long stored fuel. Further tests will then be carried out to prove that the cladding and fuel can be dried.

 

The project will use a combination of experimental testing (making use of the existing drying rig developed and installed at Leeds) and modelling of flow through the perforated cladding to inform experimental procedure and assist in prediction of process performance. The model will be validated using results from the drying rig.

Academic Lead: Bruce Hanson
Researcher: Thomas Bainbridge
Location: University of Leeds

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