Annual Report

and then to vitrify them. An important criterion
when dealing with the waste glass is its leaching
resistance.
This project is characterising the OH- containing
products and improving understanding of
the corrosion mechanism of simulated waste
glass in aqueous environments. The glass samples
are UK Magnox and borosilicate blend
glasses. The type of corrosion test used is the
MCC-1 type test. As well as standard aqueous
corrosion, deuterium (D) labelled solutions will
be used to improve the detectability of the OH
containing layers using SIMS. Characterisation
of the glass (and possibly some simulated HLW
ceramic wasteforms) outer surfaces before and
after corrosion test and depth profile is being
investigated using XRD, SEM, TEM and SIMS.
Immobilisation Options for Exotic Carbide
Fuels
Researcher: Claudia Gasparrini
Supervisor: Prof Bill Lee
Sponsor: NNL industry case award (EPSRC) as part of the
DISTINCTIVE consortium
A legacy of the UKs early research into nuclear
reactors is a range of waste types including
some from research and other reactors using fuels
which are grouped under the title “exotic”.
This project will examine some uranium carbide
(UC) fuel from the Dounreay Fast Reactor programme
for which no waste management decision
has been made. This study is improving
our understanding of the oxidation mechanism
of carbide fuels, so enabling the development
of a suitable oxide wasteform. Baseline work
has been performed on an inert carbide material,
zirconium carbide (ZrC) at Imperial College.
Oxidation studies on UC are underway using
the NNL (National Nuclear Laboratory) Preston
Laboratory facility, UK. The study on both carbides
involve characterization of the initial material
via XRD and SEM-EDX before oxidation experiments
performed in air atmosphere using
TGA/MS and furnaces. The oxidation products
are then characterized via XRD, SEM-EDX, TEM,
FIB-SIMS and BET. The in-situ monitoring of
the oxidation mechanism of these carbides is
performed in collaboration with the Laboratory
for the Study of Matter in Environmental Conditions,
Marcoule Institute for Separative Chemistry
(ICSM), Marcoule, France. In addition, the
understanding of the oxidation mechanism of
mixed carbide fuels will be carried out on a surrogate
of (U,Pu)C.
Glass Composite Materials for Radioactive
Waste Immobilisation
Researcher: Charles Hutchison
Supervisor: Prof Bill Lee
Sponsor: EPSRC DTA and Sellafield
This project examines Glass Composite Materials
(GCMs), which may contain several crystal
phases, as wasteforms for some of the Difficult
Intermediate level Wastes from the Legacy
Ponds and Furloes at Sellafield. The GCMs has
been made by Plasma Vitrification and Joule
Heated In-Container Vitrification (JHICV). Standard
characterisation techniques such as XRD,
SEM and EDX are being used to determine the
phases in GCMs before and after leach studies,
in varying conditions. This will allow tracking of
how crystalline components affect the durability
and ultimately whether these GCMs can be
safely disposed of.
Processing and Characterisation of ZrCxNy as
a Function of Stoichiometry via Carbothermic
Reduction
Researcher: Rob Harrison
Supervisors: Prof Bill Lee and Prof Robin Grimes
Sponsor: DTA EPSRC
Currently there is a renewed interest in nuclear
power as it offers an economical, low carbon so-
Centre for Nuclear Engineering Annual Report 2014-2016 50