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Abstract
W.F.G. van Rooijen, G.J. van Gendt, D.I. van der Stok and J.L. Kloosterman,
Multi-recycling Minor Actinides in a Gas-Cooled Fast Reactor,
GLOBAL 2007 - Advanced Fuel Cycles and Systems, Boise, Idaho, USA (2007).
The Gas-Cooled Fast Reactor (GFR) is a concept proposed within the Generation-IV initiative. The default core
design of the GFR within the Sixth Framework Programme of the European Union is a so-called 'self-breeder'
core that converts enough U-238 to plutonium to compensate the losses by fission and reprocessing. However,
due to the hard neutron spectrum, the GFR has a potential for transmuting Minor Actinides (MA) as well. In
this study, the CEA fuel design of the 'efficient' GFR-600 reactor core, is adapted to contain 5% to 10% of
MA. The standard fuel contains 84% uranium and 16% plutonium with prescribed composition. Adding MA reduces
the uranium contents correspondingly. The main results are that addition of MA reduces the reactivity swing,
allowing a longer irradiation interval reaching 10% FIMA. Safety parameters remain acceptable. If a proper
mix of MA material and depleted uranium is added to the reprocessed material, a fuel can be made with a
pre-defined average value of keff and virtually no reactivity swing. It is shown that addition of a small
amount of MA to the fuel increases the Breeding Gain, offsetting reprocessing losses. This opens the
possibility of obtaining a closed fuel cycle. Decay heat is about 6.5% for steady state operation; long
after shutdown the decay heat is higher for the MA fuel than for the reference U/Pu-fuel.
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