Annual Report

Spent Fuel and Waste
Management
A central component of the public acceptance
for a new nuclear build programme
is a demonstrated ability to
safely manage and dispose of high- and
intermediate-level wastes from legacy
nuclear operations. CNE research linked
to work in the Decommissioning, Immobilisation
and Storage solutIons for
NuClear wasTe InVEntories (DISTINC-
TIVE) and RCUK/NDA spent fuel university
consortia is contributing to the UKs
radwaste management programmes by
providing fundamental understanding of
key issues including behaviour of spent
AGR fuel in storage and disposal and development
of novel wasteforms for some
difficult wastes.
PDRA projects
Modelling the Thermal Output of High Dose
Spent Absorbents used in the Clean-up of
Fukushima
Researcher: Dr Michael Rushton
Supervisors: Prof Bill Lee and Dr Luc Vandeperre
Sponsors: EPSRC and Hitachi-GE Nuclear Energy
One of the main problems facing the remediation
of the Fukushima Daiichi site is the treatment
of the effluent cooling water from Units
1 – 3. Large volumes of water were injected
into the reactor cores and the spent fuel pools
which was subsequently treated in a series of
sophisticated systems. These have left large
quantities of highly con taminated adsorbents.
These are termed High Dose Spent Adsorbents
(HDSAs) and are currently stored on-site while a
suitable method of long term disposal is developed.
To this end, a low temperature processing
route is being developed at Imperial College
by which the HDSAs may be immobilised in a
low melting point glass.
To support this activity, the current project aims
to develop a model across finite element and
microstructural length scales to help underpin
the assessment of wasteform options, including
the feasibility of using the decay heat to drive
self vitrification. A radiolytic heat generation
tool is being developed to calculate the temperature
distributions in HDSA bearing wasteforms
and to provide predictions for possible wasteform
thermal/stress damage which will aid in
the optimization of processing conditions. The
project is in collaboration with the Immobilisation
Science Laboratory at Sheffield University
and with partners in Japan at the universities of
Kyushu and Tohoku and at Hitachi-GE Nuclear
Energy and is part of a recently-awarded EPSRC
grant “Advanced Waste Management Strategies
for High Dose Spent Absorbents”.
PhD/EngD Projects
Surface Analysis of Simulant UK High Level
Waste Glass
Researcher: Nor Ezzaty Ahmad
Supervisors: Prof Bill Lee and Prof Julian Jones
Sponsors: Ministry of Higher Education Malaysia and
Universiti Teknologi Malaysia
Immobilisation of high level radioactive waste
(HLW) arising from reprocessing of spent nuclear
fuel in a stable solid matrix is important to
make it safe and minimise the hazard associated
with its storage and to reduce the potential
for escape of radionuclides. The most common
method of immobilisation is to mix the
waste materials with glass forming additives
49 http://www.imperial.ac.uk/nuclear-engineering