Name: Paul Martin
Institution: University of Huddersfield
Research: Using the NGS to Help Determine the Suitability of Thoria for a Next Generation Nuclear Fuel
Paul Martin from the University of Huddersfield has been investigating the impact of defects in nuclear power fuel rods caused by high energy fission products and initial neutron bombardment.
Paul has used computer simulation techniques on the NGS to investigate 3 different scenarios -
- how the defects might affect the thoria fuel rods over a wide range of operating and extreme conditions
- a similar set of simulations incorporating uranium levels that are likely to be found in the fuel rods in a thoria based nuclear reactor
- model the effect of neutron bombardment and fast-ion radiation damage on the crystal structure of ThO2 in fuel rods
Paul’s research is particularly timely as there is increased interest in the use of thorium dioxide for nuclear power rods not least because of its comparatively high abundance in the earth’s crust and low cost. It is for this reason that, although the main fuel for nuclear power reactors is currently urania-based, thoria-based fuel is attracting much attention as an alternative high performance nuclear fuel.
Unlike uranium - which in conventional reactors must be processed to extract the tiny amount of uranium-235 in the fuel that is useful - all of the thorium dug from the ground can be usefully burnt. Moreover, when used in an energy amplifier as part of the power plant, thoria fuel produces far less radiotoxic waste than any other nuclear fuel. In addition the energy amplifier process can also be used to 'eat' spent waste from conventional reactors. Importantly thoria has the added advantage that plutonium is not produced and hence if used exclusively will not contribute towards nuclear bomb proliferation.
To carry out the simulations, Paul used METADISE and PARAPOCS programs for surface calculations, both installed on local Huddersfield NGS resources, to investigate two factors - the stability of thoria with doping levels of uranium, usually found in fuel rods, and the segregation of uranium ions to the stable {111} surface of thoria, both over a range of simulated temperatures. Further to this Paul has also carried out a molecular dynamics study, using the DL_POLY program (versions of which are installed on most NGS resources) to further study the defect structure of uranium-doped thoria.
Paul found many advantages to running his simulations on the NGS. DL_POLY scales well and thanks to the large amount of available cpu’s with the NGS, Paul has been able to use all of the available potential models to investigate a large range of doping levels over a large range of temperatures. This compares very well to the limit of 4 x 4 cpu calculations that they would have had locally at the time.
A large number of calculations were required to be able to scan the configuration space correctly but each calculation is small and doesn't need to know anything about the other calculations. The software used is easily ported to pretty much any architecture, so their jobs are particularly suited to task farming across the NGS. They have task farmed to run many METADISE jobs all at the same time instead of one after the other. This means that their sixty-four 5 minute calculations have run in 5 minutes and not 6 hours.
Dr. Paul Martin explained “Solely from a user viewpoint, the NGS is initially quite a significant task to join and carry out the authentication process that allows access. However, when one becomes more practised and confident; the NGS then provides convenient compute resources for greater simulation speed and size.”
Dr. David J. Cooke, Project PI said: "The NGS provides us with easy access to a wide range of compute resources that otherwise would not be available to us, even with considerable investment at a local level, enabling us to get our research done quickly without fuss."
Image - Molecular dynamics simulation of Uranium-doped Bulk Thoria
PI - Dr. David J Cooke
Funding body - STFC with a CCP5 Collaboration grant to modelling collaboration with Professor S.C. Parker's group at the University of Bath.
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