Event Timeslots (1)
Day 2 – June 21
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The UK has a substantial inventory of separated plutonium from its historical
reprocessing of spent nuclear fuel. The Government’s preferred option for this is re-use as
a Mixed uranium-plutonium OXide (MOX) fuel. However, 5% is not suitable for re-use
and is recommended for disposal in a Geological Disposal Facility (GDF) after having first
been immobilised in a ceramic wasteform. The NDA is evaluating processes for plutonium
immobilisation. One option being considered is ‘Disposal MOX’ which is the manufacture
of regular MOX but intended for disposal to GDF not irradiation. Regular MOX is
manufactured by heterogeneous blending of uranium and plutonium feed powders and
then forming fuel pellets through a technologically-mature cold-press and sinter process,
yielding a heterogenous MOX product. For Disposal MOX production this may be modified
by increasing the plutonium loading and introducing neutron poisons into the material
for criticality safety/safeguards purposes. Alternatively, advanced manufacturing
technologies such as Flash and Spark Plasma Sintering may provide routes to higher
quality, denser Disposal MOX. Thus, using plutonium simulants, this project will explore
using modifications to existing manufacturing routes and advanced manufacturing
technologies described above in the development of a Disposal MOX, underpinning HMG’s
policy on the direct disposal of plutonium.