University of Manchester
Dalton Nuclear Institute
MSc Project Placements offered for
The following projects are all offered by research groups within the
University of Manchester.
Project 1. Dimensional changes of nuclear graphites through the
absorption of halogen gases and its relationship to coefficient of
thermal expansion. (Nuclear Graphite Group)
Aim is introduce an alternative means of introducing crystal strain into the graphite
lattices using halogenation. Therefore to the project intends to relate the
polycrystalline behaviour of nuclear graphites to crystal strain through the absorption
of halogen gases, using optical microscopy dimensional change measurements. It is
hoped that large strains caused through the absorption of halogen gases could also be
related to those produced by irradiation.
The project is also intended to ascertain a relationship between the halogen
absorption of the differing graphites with the coefficient of thermal expansion on the
same graphites (up to 600 °C?) as the linear coefficient of thermal expansion
determines the initial growth of the graphite crystals when halogen is absorbed. This
relationship may be used to determine dimensional change and can be contrasted
against published data on the dimensional changes of nuclear graphites by fast
Methods and techniques:
SEM and Optical Microscopy for dimensional change.
Raman and EDX for phase purity
Thermal CTE experiments.?
Project 2. Dimensional changes of nuclear graphite determined using
the Bacon Factor of Anisotropy (Nuclear Graphite Group)
Bacon developed non destructive transmission x-ray diffraction technique to control
the changes in dimensions of blocks of graphite under irradiation; BAF is an
established index to measure the anisotropy of the material. It would be interesting to
compare a quantitative measurement of graphite orientation using the BAF method on
graphites prepared either by extrusion or by pressing and whether the BAF alters
under compressive strain, in comparison to HOPG.
Methods and techniques:
Micro testing –Deben micro tester.
Project 3. Depth profiling of nuclear graphites using SIMS for
decommissioning. (Nuclear Graphite Group)
Secondary ion mass spectrometry (SIMS) techniques are well established for surface
analysis as SIMS gives detailed information on atomic and molecular components on
solid surfaces with high sensitivity.
C14 found in nuclear graphite is produced during irradiation by fast neutron absorbed
by N14 with the graphites. The project would use SIMS to quantify the N14
concentration within various grades of unirradiated nuclear graphite, in order establish
where the N14 is bonded to, eg open or closed porosity and to establish any
relationships to the bonding of N14 within the graphite crystal, specific to the
measured surface area.
Ideally the N14 content of the various samples should be proportional to the surface
area and the distribution of N14 concentration with depth from the sample surface at a
range of temperatures up to 500 °C should not alter, however this assumes a uniform
distribution of the N14 within the graphite.
Project 4. Measurement of residual stresses Induced by “Ball drifting”
in chains (Materials Performance Centre)
Ball drifting is the process of pressing a hardened steel ball through a hole in an
already hardened steel plate, used for the manufacture of chains. The effect of this is
to impart some local plastic deformation and effectively add a compressive stress to
the hole walls. When applied to chain components, this significantly improves fatigue
life (by up to 30%). Such chains are used, for example, to insert and remove control
rods in the nuclear core.
Although ball drifting would appear to be a relatively straight-forwards and cheap
process, certainly for the smaller grades of chain, the residual stresses imparted by
ball drifting are not currently known. Although finite element model for the stresses
has been developed, it has not been experimentally verified. The project aims to
study the effect of the ball drifting process and suggest alternative, cheaper options
for imparting beneficial residual stresses.
This project is in close industrial collaboration with Renold (www.renold.com) – an
international company with manufacturing sites in UK, Continental Europe and China.
Part of the experimental work will be conducted at their Stockport site (Bredbury),
and support for travel/consumables costs will be provided.
Aim: to study the ball-drifting process and suggest alternative, cheaper options for
imparting beneficial residual stresses to chain components.
Objectives: to evaluate the residual stresses imparted by ball drifting, in order to
provide a base-line against which alternative techniques can be evaluated.
The magnitude, distribution and variability of stresses at each stage of the ball-drfiting
process will be evaluated, and compared with existing finite element modelling
predictions. This will be done principally by X-ray diffraction.
Strain mapping experiments using ESPI and Image Correlation will also be done to
investigate the effects of ball drifting on the deformation during proof-loading of chain
1. Kessler, O, Prinz, C Et al, Experimental study of distortion phenomena in
manufacturing chains, MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK,
2006, 37, 11-18
2. Surm, H et al, Manufacturing residual stress states in heat treatment simulation
of bearing rings, MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, JAN,
2006, 37, 52- 57
3. Martins, COD et al, Application of X-ray diffraction, micromagnetic and hole
drilling methods for residual stress determination in a ball bearing steel ring,
EXPERIMENTAL MECHANICS, 2005, 45, 344-350
4. Kobayashi, M et al, Mechanism of creation of compressive residual stress by
shot peening, INTERNATIONAL JOURNAL OF FATIGUE, 1998,20, 351-357.
Project 5. Studies of corrosion in molten salt electrolytes in the
presence of water (Materials Performance Centre)
The use of molten salt electrolytes in re-processing is a technology designed to allow
more efficient extraction and separation of U and Pu from spent nuclear fuel, and to
capture waste fission products in a waste form which can be processed to be suitable
for long term storage.
The presence of water in the KCl/LiCl eutectic mix (operating at 450-550C) under
testing at Nexia (previously BNFL) facilities at Risley has been shown to cause
localised corrosion of stainless steel piping. The active agent is postulated to be HCl,
formed by reactions of the form.
2LiCl + 2H2O 2LiOH + 2HCl
2LiCl + H2O Li2O + 2HCl
To test the hypothesis that HCl is the active agent in corrosion in molten salt
eutectics, sealed cells containing salt mixtures and test specimens of stainless steels
prepared in an inert gas atmosphere will be held at operating temperatures
representative of plant conditions for periods of 24 hours. The samples will
subsequently be examined for signs of pitting or etching. As a control, samples in cells
with ultra-dry salt will be similarly studied, and as a test to investigate if oxide or
hydroxide species are entirely benign, samples containing salt plus LiO or LiOH will
also be tested.
Project 6. Texture development during beta quenching of zirconium
alloys (Materials Performance Centre)
In zirconium alloys irradiation assisted growth is largely determined by the orientation
of the hexagonal crystal cell. In channel material of fuel assemblies a randomised
texture represents an optimum texture for minimum axial irradiation assisted growth.
Generally a randomised texture can be achieved by a -quench heat treatment after
the last reduction stage. However studies of Zr and Ti alloys have shown [1, 2] that
stresses present during to phase transformation result in variant selection of the
phase or in other words texture development due to stresses.
Fuel manufacturers are in the process of developing a beta-quench process for
channel sheet material. Sheet material will be fed through a continuous furnace
operating above the beta-transus. First results of channel material produced in this
way are very promising although in some cases unexpectedly high channel bowing
was observed. The next vital step in the development of this process is to identify
critical process parameters and to optimize them, ensuring that the texture is tightly
controlled during the process. Since stresses can have a significant effect on the
texture through variant selection, it is necessary to identify the threshold stresses
when variant selection starts to have an impact on the texture development during
beta to alpha phase transformation.
This study aims to determine the impact of fabrication and heat-treatment on the final
product texture. The inherited texture will be determined by both the original
texture and by variant selection during the formation of lamellas. This work will
investigate the effect of cooling rate and applied stresses during heat treatment on
the final texture. Material will be used to manufacture miniature samples for thermo
mechanical testing. Samples will be tested using the so-called ETMT (electro thermal
mechanical tester). This facility allows the simulation of temperature histories of the
channel material during -quenching under controlled condition and stresses. Detailed
texture studies using EBSD (electron back scatter diffraction) will be undertaken on
such samples in order to establish critical stresses at which texture deviates from
: N. Gey, M. Humbert, E. Gautier, J.L. Bechade: Study of the / phase
transformation of Zr-4 in presence of applied stresses at heating: analysis of inherited
microstructures and textures; Journal of Nuclear Materials, 328, 2004, 137-145.
: N. Stanford, P.S. Bate: Crystallographic variant selection in Ti-6Al-4V; Acta
Materialia, 52, 2004, 5215-5224.
Project 7. Construction and testing of detector for fission fragment
nuclear spectroscopy (Nuclear Physics Group)
The project “STEFF” involves construction and testing of equipment using a 252Cf
fission source held at Manchester. The apparatus will eventually be shipped to ILL
Grenoble for neutron-induced fission experiments there.
The STEFF apparatus is a new fission-fragment spectrometer with two time-of-flight
arms and associated Bragg-curve detectors. The output of the Bragg detectors is
processed using new digital electronics that allows the fragment dE/dx in gas to be
deduced. This promises to allow the atomic number of the fission fragments to be
measured in conjunction with the masses (deduced from the time-of-flight and energy
measurements). The device will be used in conjunction with an array of large NaI
detectors to study the spectra of exotic fission fragments. The proposed MSc project
involves the addition of a third arm to STEFF to allow the measurement of ternary
fission events. The student will commission a smaller ternary gas detector to be used
with STEFF and will make measurements of ternary yields and angular correlations for
Project 8. Interfacial energy transfer from irradiated ceramic oxides to
surface water (Radiation Sciences)
Heterogeneous environments are frequently encountered in the management of
radioactive waste materials, and in nuclear power plants infrastructure. Examples
include sludge and slurries in storage facilities, and porous oxide coatings on the
metal surfaces of the primary circuit in a nuclear reactor. Solid – liquid interfaces
enhance radiolytic effects on the liquid component and increased production of
oxidizing and/or corrosive radicals at an irradiated interface is a negative impact
outcome for nuclear waste management and nuclear power plant maintenance. To
control of this detrimental chemistry an understanding the transport of charge and
energy across oxide-water interfaces is required.
The objective of this research program is to construct a mechanistic description
of energy and charge exchange across interfaces in irradiated heterogeneous water-
ceramic oxide systems relevant to the nuclear power and nuclear waste management
industries. A simulation model will be developed to quantify the transfer of charge and
energy. This model will provide a predictive tool both for use in the total system
modeling of risk assessment in the transportation and storage of nuclear wastes and
in the degradation of oxide covered infrastructure in nuclear power plant.
Project 9. Radiation-induced dynamics of aqueous systems (Radiation
Radiation effects due to the neutron fields of nuclear reactors or the self-radiolysis by
-particles from transuranic waste materials are driven by fundamental chemical
processes. The interplay between of these processes depends on the type of radiation,
and damage initiated by neutrons and heavy ions is different from that induced by -
rays and fast electrons. This difference reflects the competition between intra-track
reaction of the radiation-induced radicals, diffusion, and scavenging. This competition
is modified by changes in the ion track structure.
This project will use computational stochastic methods to model the radiolysis of
water and aqueous solutions with high LET heavy ions. Studies will focus on
understanding (i) the kinetics and yield of the transient radical specie, OH, which is
responsible for much of the observed radiation-induced oxidative damage in biological
and technological systems, and (ii) the formation of the deleterious molecular
products - H2 (potentially explosive) and H2O2 (aggressively oxidative).
Project 10. Degradation of hydrocarbon polymers by radiation.
Polymeric organic materials are frequently found in association with nuclear reactor
infrastructure or waste materials in the form of polymers, solvents, or waste oils. The
radiolysis of these materials can lead to structural failure or hazardous H2 or CH4 gas
formation. Very few hydrocarbon systems have been examined in detail to obtain a
mechanism including all of the radiation processes. The lack of a detailed mechanistic
model makes it difficult to speculate on product yields for different types of radiation
or to predict the effects of radiation on uninvestigated materials. Simple cyclic
aliphatic and aromatic hydrocarbons are the most straightforward organics for
fundamental studies, and they are good surrogates for more complex organics,
including polymers. Generally, cyclic organics do not undergo C-C bond cleavage and
give fewer radiolytic products than straight chain and branched-chain hydrocarbons of
the same elemental composition.
In this project, stochastic simulations including excited states, radicals and
homogeneously distributed scavengers will be used to model the radiation chemistry
of cyclic hydrocarbons with the goal of developing a detailed mechanistic model that
can be used to predict kinetics and product yields for different types of radiation in
Project 11. Computer Programs for Dynamic Reactor Plant Analysis (In
collaboration with the Nuclear Department, HMS Sultan)
The objective of the project is to develop a flexible reactor simulator program
with a graphical user interface, based on the program M32, to investigate the coupling
of neutron physics and thermal hydraulics in reactor transient calculations.
During reactor transients, feedback from the developing thermal conditions will
affect the reactivity and therefore the fission power level. It is often sufficient to
neglect the change in the power distribution and model the time variation in power
level from a point kinetics model. This is the approach taken
in the `Telewall’ simulator used in the Nuclear Department (ND), HMS Sultan,
and is suitable for demonstrating the basic principles of dynamic reactor behaviour.
Where the fission power distribution is expected to vary significantly during a
transient, it will be necessary to couple the neutron physics and thermal hydraulic
calculations and progressively update the nuclear data according to the thermal
conditions. The pressurised water reactor (PWR) transient reactor accident code
TRACP is an example of such a coupled code. TRACP is an industrial strength code
intended for reactor safety justification and uses a computationally intensive two-fluid
model of coolant flow. The program M32 by John Moorby could be said to occupy the
middle ground between the point kinetics approach of the Telewall and the two-fluid,
coupled approach of TRACP. M32 is intended to provide a personal reactor simulator
suitable for investigation of transients in routine operation. The program is very
flexible and can model most types of thermal reactor, water or gas cooled, water or
graphite moderated, with pin or plate type fuel. Neutron physics is handled by three-
dimensional, two energy group diffusion. Heat transfer and thermal hydraulic
calculations using a mixed-fluid model, feedback into the core neutron physics to give
a realistic simulation of reactor transient behaviour.
Proposed Work Summary
M32 currently suffers from a number of limitations including: slow execution
speed, lack of tools for offline analysis of transient data, simplistic modelling of the
primary circuit, outmoded DOS-based graphics and a complicated keyboard-driven
control interface. The program is written in Quick Basic and has reached the size limit
for programs in that language, so in order to make any further improvements it is first
necessary to translate it into another programming language. This project proposes to
convert M32 into a Windows program using a modern object orientated language, and
to create a graphical user interface that displays live plant information and provides
for plant control in an intuitive way.
Furthermore, use of an object orientated programming approach will enable
M32 to be easily developed further and enhance its usefulness for research. For
example, the user could be offered the facility to select between different models for
neutron physics and thermal hydraulics. While M32 allows simulation of different
reactor types, the user is required to supply the necessary nuclear data, e.g. reaction
cross-sections for the materials present. Therefore, the project will also look at the
available methods for preparing this data, including the `open source’ DRAGON
reactor physics code from Polytechnique Montréal. Finally, test cases will have to be
prepared for input into the new M32 program in order to verify its results against
existing simulations for a number of operating transients. In particular, it would be
valuable to compare the output from a mixed-fluid code (M32) with that from a two-
fluid code (TRACP).
Project 12. Projects to be offered on cyclotron targetry for production
of radioisotopes for medial imaging (Wolfson Molecular Imaging
Further information available from Jon Billowes