Modelling advanced technology fuels for Gen IV Very High Temperature Reactors

Lead Research Organisation: Imperial College London
Department Name: Materials

Abstract

The UK signed an agreement with intent to re-join Gen IV research in the autumn of 2018 and is committed to the very high temperature reactor (VHTR) design with the ability for co-generation by producing both electricity and heat at 700-1000C. Vital to the VHTR design is trisostructural isotropic (TRISO) fuel, which is very robust. The fuel particle has itself been designed to incorporate many layers to inhibit fission product release. Current models for TRISO particle fuel have been published but are typically all based on the finite element approach and therefore do not explicitly model discontinuities such as interfaces. Given the TRISO particle fuel contains numerous different interfaces between carbon layers, fuel particle (UO2, PuO2, UCO and UC2 for example) and SiC or ZrC and also a further interface in that the TRISO particles themselves are embedded in some form of matrix material, such as carbon, this presents an interesting challenge in understanding the behaviour of the interfaces under possible reactor power changes in both normal operation and accidents. Post irradiation examination of different varieties of these TRISO fuels has shown delamination and fractures in some layers.
It is proposed to build TRISO fuel models using combined finite element and peridynamics techniques, within the ABAQUS and MOOSE codes already developed to study interfacial stresses/strains and failure, whilst maintaining fuel performance capabilities of the finite element framework. Previous work on both fuels and interfaces shows that peridynamics can study both fracture and interface delamination under thermal strains.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S023844/1 01/04/2019 30/09/2027
2461892 Studentship EP/S023844/1 30/09/2020 30/09/2024 Angelo Battistini