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University of Manchester
1.
Jones, Luke.
The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides.
Degree: 2016, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:299804 
► As of 2011, the UK had 112 tonnes (t) of plutonium dioxide PuO2 in interim storage at the Sellafield site and this is increasing by…
(more)
▼ As of 2011, the UK had 112 tonnes (t) of plutonium
dioxide PuO2 in interim storage at the Sellafield site and this is
increasing by approximately 5 t per annum with the continued
reprocessing of spent nuclear fuel. PuO2 is stored in small
quantities in a sealed multi-canister system for security and ease
of handling. During long term storage, radiolysis of the gas phase
and adsorbed species could potentially lead to canister
pressurisation and/or failure. It is of great importance to
understand the mechanisms occurring in the gas phase and to
understand the resulting gas phase composition after decades of
storage.This research investigates the radiation chemistry of two
gas phase systems in the presence or absence of inactive PuO2
surrogate material (namely cerium dioxide (CeO2) and zirconium
dioxide (ZrO2)).The systems of interest are, firstly, radiolysis of
hydrogen (H2), oxygen (O2) and argon gas mixtures utilising both
60Co gamma rays and He(2+) accelerated ions. Depletion of H2 and O2
has been investigated using gas chromatography. A bespoke manifold
has been designed to mix these gases in various ratios, suitable
reaction vessels and a subsequent sampling system has been
developed to undertake this research. The rate of H2 depletion is
independent of initial H2 concentration and radiation type. In the
presence of an oxide surface, the rate of H2 depletion is vastly
increased when compared to homogeneous studies using 60Co gamma
rays. Depletion is greatest in the presence of ZrO2. In all
systems, depletion of H2 is linear with increasing absorbed
dose.The second system of interest is the radiolysis of moist air
utilising 60Co gamma rays. Formation of nitric acid (HNO3) has been
investigated using ion chromatography to determine nitrate (NO3-)
anion production. Nitrate production increases linearly with
absorbed dose and is greater in the presence of an oxide powder.
The rate of production increases with increasing mass of oxide.
Oxalate (C2O42-) was produced radiolytically from dimerisation of
carbon dioxide and was greatest in the presence of ZrO2. Reducing
the specific surface area of CeO2 reduced the concentration of
nitrate formed when compared to higher surface area
CeO2.
Advisors/Committee Members: Pimblott, Simon.
Subjects/Keywords: Radiation; Gases
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APA (6th Edition):
Jones, L. (2016). The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:299804
Chicago Manual of Style (16th Edition):
Jones, Luke. “The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides.” 2016. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:299804.
MLA Handbook (7th Edition):
Jones, Luke. “The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides.” 2016. Web. 19 Jan 2021.
Vancouver:
Jones L. The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:299804.
Council of Science Editors:
Jones L. The Radiation Chemistry of Gases at the Interface with
Ceramic Oxides. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:299804
2.
Trownson, Glenn William.
The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions.
Degree: 2018, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313538
► Currently in the UK, spent nuclear fuel is reprocessed using the PUREX (Plutonium Uranium Reduction Extraction) process. This process generates large amounts of aqueous nitric…
(more)
▼ Currently in the UK, spent nuclear fuel is
reprocessed using the PUREX (Plutonium Uranium Reduction
Extraction) process. This process generates large amounts of
aqueous nitric acid based waste which is reduced in volume by
evaporation before being stored in stainless steel tanks pending
eventual disposal to a repository after conversion into a solid
wasteform. The corrosivity of nitric acid solutions towards these
stainless steel storage tanks is strongly affected by the presence
of oxidants that can form in situ if certain dissolved metals such
as cerium, chromium, ruthenium and neptunium are present, which is
invariably the case in nuclear reprocessing plant liquors. Such
liquors are, however, subject to radiolysis leading to the
formation of nitrous acid and NOx species in equilibrium with
nitric acid and water. The redox chemistry of irradiated
reprocessing plant liquors is therefore complex, depending on a
large number of factors including acidity, nitrate ion
concentration, temperature, pressure, radiation dose rate and the
nature/concentration of dissolved species. High acidities, high
temperatures and low dose rates favour the oxidation of species
such as Ce(III). For example, when Ce(IV) forms, the corrosion rate
of stainless steel is strongly increased since the reduction of
Ce(IV) forms a kinetically-favoured path way. Furthermore, the
presence of nitrous acid (which is radiolytically formed from
nitrate/nitric acid) can act to reduce potential corrosion
accelerators (e.g. Ce(IV)) to their non-oxidising valency states.
These dependencies are only semi-quantitatively understood at
present, hampering useful prediction of actual effects when
conditions are changed. The research presented within this thesis
is divided between two experimental campaigns which are
interrelated by their applicability to highly active storage tank
conditions; I. An investigation into the conditions which effect
the radiolytic production of nitrous acid in nitric acid based
solutions was undertaken. This included the quantitative
measurement of the steady state concentration of nitrous acid
experienced under different conditions. The conditions investigated
include temperature, dose rate, gaseous headspace and liquor
composition in order to elucidate which factors are of importance
in estimating the concentration of nitrous acid which can be
expected at the base of a highly active storage tank. The major
result of this campaign was that nitrous acid data collected could
be used to formulate a g-value of nitrous acid formation (which was
found to be 0.71) and this value was used to calculate the nitrous
acid production rate expected within a highly active storage tank
which is a pre-requisite of underpinning the corrosion chemistry
within. II. Investigation into the potential formation of in situ
corrosion accelerators in a reprocessing liquor simulant was
undertaken. For this, a bespoke experimental rig has been designed,
built and operated in order to identify the valency of potential
corrosion accelerators at high temperatures…
Advisors/Committee Members: Pimblott, Simon.
Subjects/Keywords: Corrosion; Nitric acid; Reprocessing; Nitrous acid; Cerium
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APA ·
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MLA ·
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CSE |
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Manager
APA (6th Edition):
Trownson, G. W. (2018). The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313538
Chicago Manual of Style (16th Edition):
Trownson, Glenn William. “The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions.” 2018. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313538.
MLA Handbook (7th Edition):
Trownson, Glenn William. “The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions.” 2018. Web. 19 Jan 2021.
Vancouver:
Trownson GW. The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313538.
Council of Science Editors:
Trownson GW. The High Temperature Corrosivity of Radiolysed Nitric
Acid Solutions. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313538
University of Manchester
3.
Donoclift, Thomas Ashley.
The Radiolytic Steady-State and Factors Controlling H2
Production.
Degree: 2017, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:307832
► Sellafield is home to the UK’s largest repository of nuclear waste, including reprocessed uranium and plutonium, as well as a backlog of unprocessed used fuel…
(more)
▼ Sellafield is home to the UK’s largest repository
of nuclear waste, including reprocessed uranium and plutonium, as
well as a backlog of unprocessed used fuel and waste kept in
outdated storage facilities; commonly referred to as “legacy
waste”. For this reason, Sellafield has often been called the most
hazardous place in Western Europe and as such, is currently
undergoing a multi-billion pound decommissioning and clean-up
operation. Each on-site facility has unique challenges associated
with it, many of them presenting situations where the radiation
chemistry aspects of the material degradation are not well
understood. The key factors that can affect water radiolysis
processes in the Sellafield challenges are a high pH environment,
the presence of magnesium hydroxide, the presence of iron oxide,
and the presence of organic materials. This work examines the
effect each of these factors has on H2 and H2O2 production in water
radiolysis as well as developing a computational model to offer
some understanding to the kinetic behaviour of water radiolysis
under such conditions. The computational model was able to
replicate experimental measurements of radiolytic H2 and H2O2
production in both aerated and deaerated water at neutral pH, and
provide a further understanding of the role of dissolved oxygen in
water radiolysis. Measurements of H2O2 from solutions containing
NaOH have shown that an increase in pH generally results in a
higher steady state of H2O2, while measurements of H2 show a
similar increase with a maximum production rate at pH ~11. The
model was also able to closely replicate these experimental
measurements with some over prediction, which highlights a gap in
our understanding of high pH radiolysis and also brings into
question the validity of the estimated rate constant for the
reaction: O- + O2- -> 2OH- + O2 k= 6.0×108 M-1 s-1which was
originally determined from kinetic model calculations designed to
describe the decay of ozonide (O3ˉ) during pulse-radiolysis studies
of high pH solutions conducted byK. Sehested et al in 1982.The
radiolysis of magnesium hydroxide slurry also resulted in an
increased yield of hydrogen gas but had little effect on the yield
of hydrogen peroxide. The hydrogen yield was 0.52 molecules per
100eV while a NaOH solution of equivalent pH gave a yield of 0.27,
however interference from carbonate may be the cause of the
increased yield. A surface effect was also estimated to contribute
0.05 molecules per 100 eV to the hydrogen gas yield.Hydrogen gas
and hydrogen peroxide was measured from the radiolysis of aqueous
methanol. This was modelled with a near agreement, but
modifications to the model were necessary; highlighting areas of
the model that need improvement, as well as providing a reaction
scheme from which a more comprehensive model for aqueous methanol
radiolysis could be developed.
Sellafield is home to the UK’s largest repository
of nuclear waste, including reprocessed uranium and plutonium, as
well as a backlog of unprocessed used fuel and waste kept in
outdated…
Advisors/Committee Members: Pimblott, Simon.
Subjects/Keywords: nuclear waste; radiation chemistry; radiolysis; hydrogen production; water radiolysis; computational modelling
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APA ·
Chicago ·
MLA ·
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CSE |
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Donoclift, T. A. (2017). The Radiolytic Steady-State and Factors Controlling H2
Production. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:307832
Chicago Manual of Style (16th Edition):
Donoclift, Thomas Ashley. “The Radiolytic Steady-State and Factors Controlling H2
Production.” 2017. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:307832.
MLA Handbook (7th Edition):
Donoclift, Thomas Ashley. “The Radiolytic Steady-State and Factors Controlling H2
Production.” 2017. Web. 19 Jan 2021.
Vancouver:
Donoclift TA. The Radiolytic Steady-State and Factors Controlling H2
Production. [Internet] [Doctoral dissertation]. University of Manchester; 2017. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:307832.
Council of Science Editors:
Donoclift TA. The Radiolytic Steady-State and Factors Controlling H2
Production. [Doctoral Dissertation]. University of Manchester; 2017. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:307832
University of Manchester
4.
Barr, Logan.
Radiation resistance of novel polymeric
encapsulants.
Degree: 2015, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:264000
► The generation of nuclear energy leads to the generation of contaminated, radioactive wastes. The current strategy in the UK is to dispose of high and…
(more)
▼ The generation of nuclear energy leads to the
generation of contaminated, radioactive wastes. The current
strategy in the UK is to dispose of high and intermediate level
wastes to a geological disposal facility with no possibility for
retrieval. The waste is contained in an encapsulation matrix, which
is usually cement, however cement is unsuitable for certain waste
types, for which epoxy resins have been proposed as an alternative.
The radiation resistance of two candidate epoxy/amine resin
formulations under repository conditions were tested with regards
to the degradation of the backbone structure and the release of
potential organic ligands from the polymer. The difference in the
polymers was the choice of amine curing agent. Analysis of the
polymer by infra-red spectroscopy and nuclear magnetic resonance
spectroscopy revealed that the carbon nitrogen bonds are the most
susceptible to radiation damage, regardless of the atmospheric and
aqueous environment. The presence of an aqueous phase greatly
reduces the availability of oxygen and reduces the rate of
degradation when irradiated under an atmosphere of air. The
properties of the aqueous phase has little effect on the
degradation of the polymer. Thermal analysis revealed that the
effects of the environment are limited to a thin surface layer of
the polymer. Leachate analysis revealed that both organic and
nitrogen containing compounds are leached from the polymer when
irradiated in pure water. Under repository conditions however very
little carbon and nitrogen is observed, suggesting that the calcium
hydroxide present in repositories is capable of removing the
leached species from solution. The generation of nitrate ions from
air radiolysis over water is suppressed in the presence of the
polymers, suggesting that nitrate is removed from solution by
leached species or reaction with the polymer.
Advisors/Committee Members: Pimblott, Simon.
Subjects/Keywords: Radiation; Polymers; Nuclear waste; Geological disposal; Epoxy resisn
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APA ·
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MLA ·
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CSE |
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Barr, L. (2015). Radiation resistance of novel polymeric
encapsulants. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:264000
Chicago Manual of Style (16th Edition):
Barr, Logan. “Radiation resistance of novel polymeric
encapsulants.” 2015. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:264000.
MLA Handbook (7th Edition):
Barr, Logan. “Radiation resistance of novel polymeric
encapsulants.” 2015. Web. 19 Jan 2021.
Vancouver:
Barr L. Radiation resistance of novel polymeric
encapsulants. [Internet] [Doctoral dissertation]. University of Manchester; 2015. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:264000.
Council of Science Editors:
Barr L. Radiation resistance of novel polymeric
encapsulants. [Doctoral Dissertation]. University of Manchester; 2015. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:264000
University of Manchester
5.
Unsworth, Thomas James.
Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste.
Degree: 2018, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314172
► Organic liquid wastes produced by the civil nuclear industry are often contaminated with radionuclides. These wastes must be consigned to a repository for long-term storage…
(more)
▼ Organic liquid wastes produced by the civil nuclear
industry are often contaminated with radionuclides. These wastes
must be consigned to a repository for long-term storage or
pre-treatments like incineration can be carried out to eliminate
the organic component. This can be costly, inefficient or harmful
to the environment. Waste owners have sought alternative
technologies to break down their organic wastes. Established
processes used in other industries like water treatment and
innovative solutions like the Arvia(TM) Process aim to provide a
cheaper and cleaner replacement for incineration. At this point in
time there has been little research into understanding the negative
effects of radiation on the Arvia(TM) Process and the fate of
radionuclides in the post-treatment effluent. The research carried
out in this EngD project was focused on two experimental themes.
Firstly, monitoring the behaviour of an inactive surrogate for
caesium-137 during adsorption and electrochemical oxidation of
citric acid, a complexing agent used in nuclear decontamination.
Secondly, gamma-ray irradiation and ion beam irradiation
experiments of carbon-based Nyex(TM) adsorbent. Laboratory
experiments using a bench-scale Arvia(TM) Process unit were carried
out. Mixtures of citric acid and caesium chloride were used. The
adsorption and breakdown of citric acid and the movement of caesium
ions were evaluated. A cobalt-60 irradiator was employed to test
the effect of gamma-rays (1.17 MeV and 1.33 MeV) on the adsorbent
used in the system. At low doses of gamma-rays, Nyex(TM) showed
little change both structurally and in performance characteristics.
A noticeable effect of gamma-ray irradiation on citric acid
adsorption was found at high doses. Electrokinetic migration of
caesium ions across the Y-cell was measured and evaluated; the
associated ion flux was increased by the presence of citric acid. A
novel technique to control the migration of caesium ions was
performed. We now have a better understanding of how radionuclides
behave in the Arvia(TM) Process; an indication of the overall
treatment efficacy of contaminated organic complexing agents; and
the promising ability of Nyex(TM) to perform as intended under
ionising radiation. This work could form part of a case for the
application of the Arvia(TM) Process to nuclear wastes if that
option is pursued. This case would benefit from more research
targeted at radioactive organic wastes and the support of industry
leaders seeking to employ innovative technology.
Advisors/Committee Members: PIMBLOTT, SIMON SM, Heath, Sarah, Pimblott, Simon.
Subjects/Keywords: Arvia; Nyex; Adsorption; Electrochemical oxidation; Organic waste; Radioactive waste
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Unsworth, T. J. (2018). Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314172
Chicago Manual of Style (16th Edition):
Unsworth, Thomas James. “Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste.” 2018. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314172.
MLA Handbook (7th Edition):
Unsworth, Thomas James. “Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste.” 2018. Web. 19 Jan 2021.
Vancouver:
Unsworth TJ. Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314172.
Council of Science Editors:
Unsworth TJ. Radiation effects and surrogate radionuclide behaviour
during the electrochemical oxidation of aqueous organic
waste. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314172
6.
Brown, Ashley Richards.
The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste.
Degree: 2014, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:216843
► Microorganisms control many processes pertinent to the stability of radwaste inventories in nuclear storage and disposal facilities. Furthermore, numerous subsurface bacteria, such as Shewanella spp.…
(more)
▼ Microorganisms control many processes pertinent to
the stability of radwaste inventories in nuclear storage and
disposal facilities. Furthermore, numerous subsurface bacteria,
such as Shewanella spp. have the ability to couple the oxidation of
organic matter to the reduction of a range of metals, anions and
radionuclides, thus providing the potential for the use of such
versatile species in the bioremediation of radionuclide
contaminated land. However, the organisms promoting these processes
will likely be subject to significant radiation doses. Hence, the
impact of acute doses of ionizing radiation on the physiological
status of a key Fe(III)-reducing organism, Shewanella oneidensis,
was assessed. FT-IR spectroscopy and MALDI-TOF-MS suggested that
the metabolic response to radiation is underpinned by alterations
to proteins and lipids. Multivariate statistical analysis indicated
that the phenotypic response was somewhat predictable although
dependent upon radiation dose and stage of recovery. In addition to
the cellular environment, the impact of radiation on the
extracellular environment was also assessed. Gamma radiation
activated ferrihydrite and the usually recalcitrant hematite for
reduction by S. oneidensis. TEM, SAED and Mössbauer spectroscopy
revealed that this was a result of radiation induced changes to
crystallinity. Despite these observations, environments exposed to
radiation fluxes will be much more complex, with a range of
electron acceptors, electron donors and a diverse microbial
community. In addition, environmental dose rates will be much lower
than those used in previous experiments. Sediment microcosms
irradiated over a two month period at chronic dose rates exhibited
enhanced Fe(III)-reduction despite receiving potentially lethal
doses. The microbial ecology was probed throughout irradiations
using pyrosequencing to reveal significant shifts in the microbial
communities, dependent on dose and availability of organic electron
donors. The radiation tolerance of an algal contaminant of a spent
nuclear fuel pond was also assessed. FT-IR spectroscopy revealed a
resistant phenotype of Haematococcus pluvialis, whose metabolism
may be protected by the radiation induced production of an
astaxanthin carotenoid. The experiments of this thesis provide
evidence for a range of impacts of ionizing radiation on
microorganisms, including the potential for radiation to provide
the basis for novel ecosystems. These results have important
implications to the long-term storage of nuclear waste and the
geomicrobiology of nuclear environments.
Advisors/Committee Members: GOODACRE, ROY R, PIMBLOTT, SIMON SM, Goodacre, Roy, Lloyd, Jonathan, Pimblott, Simon.
Subjects/Keywords: ionizing radiation; radiation biology; ionising radiation; nuclear geomicrobiology; Shewanella; Haematococcus; microbial Fe(III) reduction
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Brown, A. R. (2014). The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:216843
Chicago Manual of Style (16th Edition):
Brown, Ashley Richards. “The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste.” 2014. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:216843.
MLA Handbook (7th Edition):
Brown, Ashley Richards. “The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste.” 2014. Web. 19 Jan 2021.
Vancouver:
Brown AR. The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste. [Internet] [Doctoral dissertation]. University of Manchester; 2014. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:216843.
Council of Science Editors:
Brown AR. The impact of ionizing radiation on microbial cells
pertinent to the storage, disposal and remediation of radioactive
waste. [Doctoral Dissertation]. University of Manchester; 2014. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:216843
7.
Ipatova, Iuliia.
Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors.
Degree: 2018, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314122
► In this project, we have assessed the structural tolerance of advanced refractory alloys to simulated nuclear fusion reactor environments, by using intense proton beams to…
(more)
▼ In this project, we have assessed the structural
tolerance of advanced refractory alloys to simulated nuclear fusion
reactor environments, by using intense proton beams to mimic fusion
neutron damage and analysing the proton damaged structures using
in-situ/ex-situ transmission electron microscopy and nano-hardness
measurements. Refractory metals such as tungsten or tantalum, and
their binary alloy combinations, are considered as promising
structural materials to withstand the unprecedented high heat loads
and fast neutron/helium fluxes expected in future
magnetically-confined fusion reactors. Tungsten is currently the
frontrunner for the production of plasma-facing components for
fusion reactors. The attractiveness of tungsten as structural
material lies in its high resistance to plasma-induced sputtering,
erosion and radiation-induced void swelling, together with its
thermal conductivity and high-temperature strength. Unfortunately,
the brittle nature of tungsten hampers the manufacture of reactor
components and can also lead to catastrophic failure during reactor
operations. We have focused on two potential routes to enhance the
ductility of tungsten-containing materials, namely alloying
tungsten with controlled amounts of tantalum, and using
alternatively tantalum-based alloys containing specific tungsten
additions, either as a full-thickness structural facing material or
as a coating of first wall reactor components. The aim was to
investigate the formation and evolution of radiation-induced
damaged structures in these material solutions and the impact of
those structures on the hardness of the material. The main results
of this work are: (1) the addition of 5wt%Ta to W leads to
saturation in the number density and average dimensions of the
radiation-induced a/2<111> dislocation loops formed at 350C,
whereas in W the loop length increases progressively and evolves
into dislocation strings, and later into hydrogen bubbles and
surface blisters, (2) the recovery behaviour of proton irradiated
W5wt.%Ta alloy is characterized by dislocation loop growth at
600-900C, whereas voids form at 1000C by either vacancy absorption
or loop collapse, (3) the presence of radiation-induced
a<100> loops at 590C in Ta hinders the formation and ordering
of voids observed with increasing damage levels at 345C, (4) the
addition of 5-10wt.%W to Ta delays the evolution of a/2<111>
dislocation loops with increasing damage levels, and therefore the
appearance of random voids. These results expand the composition
palette available for the safe selection of refractory alloys for
plasma facing components with enhanced, or at least predictable,
tolerance to the heat-radiation flux combinations expected in
future nuclear fusion plants.
Advisors/Committee Members: PREUSS, MICHAEL M, PIMBLOTT, SIMON SM, Jimenez-Melero, Enrique, Preuss, Michael, Pimblott, Simon.
Subjects/Keywords: Fusion energy; Nuclear reactors; Radiation damage; Electron microscopy; Refractory alloys
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APA (6th Edition):
Ipatova, I. (2018). Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314122
Chicago Manual of Style (16th Edition):
Ipatova, Iuliia. “Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors.” 2018. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314122.
MLA Handbook (7th Edition):
Ipatova, Iuliia. “Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors.” 2018. Web. 19 Jan 2021.
Vancouver:
Ipatova I. Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314122.
Council of Science Editors:
Ipatova I. Nanoscale structure damage in irradiated W-Ta alloys for
nuclear fusion reactors. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314122
University of Manchester
8.
Tweddle, Zoë Louise.
Experimental and Computational Analysis of Nitric Acid
Radiolysis.
Degree: 2020, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:326924
► Nitric acid is exposed to a variety of radiation sources at various stages of the nuclear fuel cycle, causing the destruction of the nitric acid…
(more)
▼ Nitric acid is exposed to a variety of radiation
sources at various stages of the nuclear fuel cycle, causing the
destruction of the nitric acid molecule and the production of
various reactive nitrogen and oxygen containing species, such as
NO3•, •O• and NO2•. These, in turn, can react with water
radiolysis products creating products such as nitrous acid,
hydrogen peroxide and potentially dangerous gases such as H2 and
NOx. Their production results in the de-acidification and
de-nitrification of the solutions and can disrupt and degrade
sealed systems with increased pressure and container damage. As
nitric acid is a key component in the PUREX process and present in
HAL storage tanks (HASTs), in which the chemical disruption of the
solution can lead to the precipitation of radioactive isotopes and
the destruction of nitric acid produced pacification layers on the
stainless-steel containers, compromising their structural
integrity. Whilst the consequences of nitric acid radiolysis are
known, the specific radiolytic processes important in long-term
irradiation are less understood and studied. A computational model
of nitric acid radiolysis was attempted, though the complexity of
nitric acid radiolysis resulted in a model that was limited in
relevance. Experimental data was collected to support the modelling
process, but due to the distinct lack of literature data was a far
more involved process than initially thought and became the main
focus of this project.
Advisors/Committee Members: PIMBLOTT, SIMON SM, SIMS, HOWARD H, Livens, Francis, Pimblott, Simon, Sims, Howard.
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APA (6th Edition):
Tweddle, Z. L. (2020). Experimental and Computational Analysis of Nitric Acid
Radiolysis. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:326924
Chicago Manual of Style (16th Edition):
Tweddle, Zoë Louise. “Experimental and Computational Analysis of Nitric Acid
Radiolysis.” 2020. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:326924.
MLA Handbook (7th Edition):
Tweddle, Zoë Louise. “Experimental and Computational Analysis of Nitric Acid
Radiolysis.” 2020. Web. 19 Jan 2021.
Vancouver:
Tweddle ZL. Experimental and Computational Analysis of Nitric Acid
Radiolysis. [Internet] [Doctoral dissertation]. University of Manchester; 2020. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:326924.
Council of Science Editors:
Tweddle ZL. Experimental and Computational Analysis of Nitric Acid
Radiolysis. [Doctoral Dissertation]. University of Manchester; 2020. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:326924
9.
Knox, David Andrew.
High resolution gas phase spectroscopy at solid / solid
interfacial regions.
Degree: 2015, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:282767
► Understanding the behaviour of polymers which are located in the presence of nuclear materials is important in order to predict the lifespan of the materials.…
(more)
▼ Understanding the behaviour of polymers which are
located in the presence of nuclear materials is important in order
to predict the lifespan of the materials. Artificial ageing
experiments are undertaken at elevated temperatures to infer how
the materials may age. This study was concerned with the monitoring
of trace gases (H2O, CO2, CO and acetic acid) within a materials
ageing vessel which contained ethylene-vinyl acetate (EVA) polymer
and uranium in order to deduce the rate of polymer degradation
and/or uptake of the gases by uranium.A novel circular
multi-reflective (CMR) cell was designed, developed and deployed in
situ in order to extend the optical pathlength within the vessel to
improve detection limits of the trace gases. One cell was located
at the 6 millimetre solid / solid interfacial region between
cylindrical coupons of the EVA polymer and uranium, to enable
representative sampling in proximity to where the gases were
evolved, adsorbed or reacted. The unique planar star-like beam
profile of the CMR cell was crucial in enabling detection within
this narrow interfacial region. A second CMR cell was incorporated
within the vessel headspace, above the two material coupons, to
address a specific research problem which aimed to ascertain
whether differences in the gaseous composition existed between the
two regions, which would indicate poor gas mixing. Two
spectroscopic techniques were employed in conjunction with the CMR
cells to monitor the trace gases: these comprised broadband
absorption spectroscopy (BBAS) and tunable diode laser absorption
spectroscopy (TDLAS). Near-infrared (IR) radiation sources, in the
form of diode lasers, a superluminescent light emitting diode
(SLED) and supercontinuum (SC) source were utilised in BBAS
experiments. TDLAS was used for the detection of CO2, CO and H2O,
whilst BBAS was used for the detection of acetic acid, and other
potential unknown species. The requirement for using near-IR
radiation was a consequence of using flexible silica-based optical
fibres to remotely monitor the vessel which was located within a
temperature controlled chamber. As a result, this was the first
demonstration of CMR cells being used in conjunction with near-IR
radiation sources.An optical pathlength of 69 cm was achieved
within the materials ageing vessel, which led to the following
limits of detection at 75 °C, 150 Torr with a 10 second averaging
time: H2O = 3 ppm; acetic acid = 157 ppm; CO2 = 596 ppm and CO =
37500 ppm. Manufacturing issues with the cell optics, coupled with
monitoring weak ro-vibrational absorption features led to
considerably higher limits of detection than expected.The CMR
spectroscopic system was used successfully to observe the
outgassing trend of partially cured EVA polymer, which was shown to
depend on cure time. A key finding of this research, however, was
the observation of a difference between the interfacial gaseous
composition versus the headspace gas in a system that contained
both a source and sink material (i.e. one that evolved, and one
that adsorbed gases).…
Advisors/Committee Members: PIMBLOTT, SIMON SM, Martin, Philip, Pimblott, Simon.
Subjects/Keywords: spectroscopy; circular multi-reflection; interfacial region; materials ageing
…13
ABSTRACT
University of Manchester — David Andrew Knox — Doctor of Philosophy
High… …he has given The
University of Manchester certain rights to use such Copyright, including…
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MLA ·
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Manager
APA (6th Edition):
Knox, D. A. (2015). High resolution gas phase spectroscopy at solid / solid
interfacial regions. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:282767
Chicago Manual of Style (16th Edition):
Knox, David Andrew. “High resolution gas phase spectroscopy at solid / solid
interfacial regions.” 2015. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:282767.
MLA Handbook (7th Edition):
Knox, David Andrew. “High resolution gas phase spectroscopy at solid / solid
interfacial regions.” 2015. Web. 19 Jan 2021.
Vancouver:
Knox DA. High resolution gas phase spectroscopy at solid / solid
interfacial regions. [Internet] [Doctoral dissertation]. University of Manchester; 2015. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:282767.
Council of Science Editors:
Knox DA. High resolution gas phase spectroscopy at solid / solid
interfacial regions. [Doctoral Dissertation]. University of Manchester; 2015. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:282767
10.
Schofield, Jennifer.
Effects of Ionising Radiation on Nuclear
Materials.
Degree: 2016, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301281
► The prediction of energy loss properties and track structure effects of ionising radiation in materials is of importance to many areas of science, healthcare and…
(more)
▼ The prediction of energy loss properties and track
structure effects of ionising radiation in materials is of
importance to many areas of science, healthcare and technology,
especially the nuclear industry. This study examines three
different aspects of the electronic effects of ionising radiation
on solid materials: the calculation of inelastic cross sections,
the measurement of charge state fractions of ions through
materials, and the radiolytic hydrogen produced from slurries under
gamma irradiation.Predicting how ionising radiation will interact
with matter often utilises collision cross sections for the
interaction process. The electronic energy loss cross sections of
ions in materials are predicted using a novel formalism requiring
only the dipole oscillator strength distribution (DOSD) of the
material of interest. DOSDs are constructed for silicon carbide and
various oxides of interest to the nuclear industry. Electronic
collision cross sections as well as average energy loss properties
for incident protons, helium and other ions are calculated using
the developed formalism. The formalism is shown to predict
macroscopic energy loss properties well, especially at higher
energies, suggesting the formalism is an acceptable simple yet
elegant method for calculating electronic cross sections for use in
Monte Carlo simulations of radiation track structures.The charge of
an ion in a material affects the rate of energy loss during the
passage through that material. The charge state fractions of
lithium and helium ions in several metallic materials pertinent to
the nuclear industry are measured and compared in order to improve
the understanding of ion charge states in a radiation track
structure. The new charge state fraction measurements show a clear
dependence on material properties which appears to correlate with
the ionisation potential of the material; however, a full
understanding of the dependence is lacking.Radiolytic hydrogen
production is of importance when considering the safety of spent
nuclear material in cooling ponds and after disposal. One proposed
clad coating for accident tolerant fuel currently under
investigation is silicon carbide however its radiation chemistry is
relatively unknown. The hydrogen produced from gamma-irradiated
silicon carbide water slurries is investigated. The measured yield
of H2 produced is greater than would be expected from a mixture
rule. This excess production of H2 is believed to be due to
transfer of energy from the solid ceramic to the aqueous phase by
either low energy electrons or exciton dissociation at the
water-carbide interface.These three areas of investigation are
complementary aspects of the interaction of ionising radiation with
solid material and add to the knowledge base necessary for an
acceptable risk-based justification for sustainable energy
production by nuclear fission power plants.
Advisors/Committee Members: BILLOWES, JONATHAN J, Billowes, Jonathan, Pimblott, Simon.
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APA ·
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MLA ·
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Schofield, J. (2016). Effects of Ionising Radiation on Nuclear
Materials. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301281
Chicago Manual of Style (16th Edition):
Schofield, Jennifer. “Effects of Ionising Radiation on Nuclear
Materials.” 2016. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301281.
MLA Handbook (7th Edition):
Schofield, Jennifer. “Effects of Ionising Radiation on Nuclear
Materials.” 2016. Web. 19 Jan 2021.
Vancouver:
Schofield J. Effects of Ionising Radiation on Nuclear
Materials. [Internet] [Doctoral dissertation]. University of Manchester; 2016. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301281.
Council of Science Editors:
Schofield J. Effects of Ionising Radiation on Nuclear
Materials. [Doctoral Dissertation]. University of Manchester; 2016. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:301281
University of Manchester
11.
Bates, Katherine.
The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems.
Degree: 2017, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310938
► Research was conducted into the radiolytic hydrogen production from the gamma radiolysis of n-dodecane and TODGA. Experiments were conducted to determine the value of G(H2)…
(more)
▼ Research was conducted into the radiolytic hydrogen
production from the gamma radiolysis of n-dodecane and TODGA.
Experiments were conducted to determine the value of G(H2) for neat
n-dodecane, TODGA, and mixtures of the two. Variables investigated
were the dependence of G(H2) on dose, the effect of purging with
argon, and the dose rate (between 21 and 360 Gy/min). The value of
G(H2) for n-dodecane was observed to be dependent on the dose, the
dose rate, and exposure to the atmosphere. When the absorbed dose
increased to above 5kGy, the value of G(H2) decreased. Increasing
the dose rate was observed to decrease the value of G(H2). Purging
n-dodecane with argon resulted in an increased value of G(H2). When
neat TODGA was irradiated, purging the system with argon did not
cause an effect on the yield of hydrogen. When the absorbed dose
increased above 5kGy, the value of G(H2) increased; the opposite
behaviour to n-dodecane. Irradiating mixtures of n-dodecane and
TODGA results in a decreased yield of hydrogen when compared to
extrapolations of from neat n-dodecane and TODGA. A model was
constructed for hydrocarbon radiolysis, using an iterative approach
to solving a set of simultaneous equations, based on the reactions
of hydrocarbon radicals after radiolysis. The model did not include
a mechanism for the experimentally observed dependence of G(H2) on
the dose rate of the incident gamma-irradiation. In the future
reprocessing system EURO-GANEX, a solution of 0.2M TODGA and 0.5M
DMDOHEMA in a hydrocarbon based diluent is expected to be used as
the organic extractant phase. The experimentally determined values
of G(H2) for 0.2M TODGA in n-dodecane were as follows. Under
aerated conditions: (0.208+-0.004)u mol/J during the LDR,
(0.158+-0.003)u mol/J for absorbed doses above 5kGy; and (0.32+-
0.01)u mol/J for argon purged solutions in the
LDR.
Advisors/Committee Members: SHARRAD, CLINT CA, Pimblott, Simon, Sharrad, Clint.
Subjects/Keywords: n-dodecane; TODGA; radiolysis; hydrogen; radiolytic
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MLA ·
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CSE |
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bates, K. (2017). The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310938
Chicago Manual of Style (16th Edition):
Bates, Katherine. “The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems.” 2017. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310938.
MLA Handbook (7th Edition):
Bates, Katherine. “The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems.” 2017. Web. 19 Jan 2021.
Vancouver:
Bates K. The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems. [Internet] [Doctoral dissertation]. University of Manchester; 2017. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310938.
Council of Science Editors:
Bates K. The Radiolytic Hydrogen Production from TODGA and
Associated Reprocessing Systems. [Doctoral Dissertation]. University of Manchester; 2017. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:310938
12.
Horne, Gregory Peter.
An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems.
Degree: 2015, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:275818
► Plutonium Uranium Reduction EXtraction (PUREX) technology is a solvent extraction process used to recover plutonium and uranium from spent nuclear fuel. The solvent system is…
(more)
▼ Plutonium Uranium Reduction EXtraction (PUREX)
technology is a solvent extraction process used to recover
plutonium and uranium from spent nuclear fuel. The solvent system
is composed of an aqueous nitric acid phase in contact with an
organic phase made up of tributyl phosphate in an organic diluent.
During the separation process, the PUREX solvent system is subject
to an intense multi-component radiation field (gamma rays, alpha
particles, beta particles, neutrons, and fission fragments)
rendering it susceptible to radiolytic degradation, which reduces
its performance. Despite the PUREX process being used for over
sixty years, a complete quantitative mechanistic understanding of
the radiolytic degradation processes is not available. Nitrous acid
is the most significant radiolytic degradation product of nitric
acid, especially as its chemical and physical properties alter the
formulation of the PUREX solvent system. Furthermore, nitrous acid
exhibits complex redox relationships with a number of actinides,
with plutonium being of greatest concern to the performance of the
PUREX process. A combination of experimental and computational
(stochastic and deterministic) techniques have been used to
investigate the radiolysis of the PUREX solvent system’s aqueous
phase, specifically the radiolytic formation of nitrous acid, and
its conjugate base nitrite, as a function of solvent system
formulation, absorbed dose (up to 1.7 kGy), and radiation quality
(cobalt-60 gamma rays and alpha particles from plutonium and
americium alpha decay). The research presented in this thesis
focuses on: (i) the experimental radiation chemistry of solutions
of nitric acid and sodium nitrate over the range of concentrations
1 × 10−3 to 6 mol dm−3, and (ii) the development of a multi-scale
modelling approach for evaluating the radiolysis of aqueous systems
in terms of reaction mechanisms. The experimental and modelling
studies provide insight into the radiation chemistry of the PUREX
solvent system’s aqueous phase, mechanistically demonstrating how
the radiation chemical yield of nitrous acid and nitrite is
dependent upon the interplay between non-homogeneous radiation
track chemistry and secondary bulk homogeneous chemistry. This
interplay is influenced by low pH, the presence of chemical
scavengers and redox active metal ions, and radiation quality.
These findings will act as a benchmark for the development of
advanced reprocessing schemes, which must seriously consider how
modifications in solvent system formulation and fuel composition
may affect this dynamic interplay, and ultimately the generation of
secondary highly active liquid waste.
Advisors/Committee Members: SHARRAD, CLINT CA, Sharrad, Clint, Pimblott, Simon.
Subjects/Keywords: PUREX; Radiolysis; Nitric acid; Nitrate; Gamma; Plutonium; Americium; Multi-scale modelling
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Horne, G. P. (2015). An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:275818
Chicago Manual of Style (16th Edition):
Horne, Gregory Peter. “An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems.” 2015. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:275818.
MLA Handbook (7th Edition):
Horne, Gregory Peter. “An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems.” 2015. Web. 19 Jan 2021.
Vancouver:
Horne GP. An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems. [Internet] [Doctoral dissertation]. University of Manchester; 2015. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:275818.
Council of Science Editors:
Horne GP. An Experimental and Computational Investigation into the
Radiolysis of PUREX Solvent Systems. [Doctoral Dissertation]. University of Manchester; 2015. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:275818
13.
Smith, Marisa.
Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water.
Degree: 2018, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313044
► The thermalization processes of low energy electrons are important in a number of fields. The low energy secondary electron accounts for significant amounts of energy…
(more)
▼ The thermalization processes of low energy
electrons are important in a number of fields. The low energy
secondary electron accounts for significant amounts of energy
dissipation from a high energy radiation particle. Many of these
primary radiation particles are of technological and medical
significance, including the nuclear industry, astrochemistry,
astrobiology, biology and hadron therapy. Understanding these low
energy processes is crucial to understanding any science that is
concerned with radiation effects in materials. In order to
accurately predict the effects of radiation, radiation track
chemistry including the contribution of low energy electrons first
must be understood. The ballistic simulations of the electron on a
collision by collision basis allow scientific study of
thermalization processes not available to experimentalists; and can
illuminate the intricacies of these processes. A computational
Monte Carlo simulation approach was developed to calculate various
parameters of the thermalization process of the low energy
electron. Multiple simulation method types were used to allow
future comparison of various factors to experimental data. The
method types vary from computationally inexpensive, but
unrealistic, to a very computationally expensive but realistic
simulation process. Experimental cross-sections for the gas and
amorphous ice phases of water are used for sub excitation electrons
of energies in the range of 1-20 eV and ≤100 eV, respectively.
The density normalized gas phase is used to compare to other
cross-sectional data. The amorphous ice cross-sections are used to
represent the liquid phases of water. The thermalization distances,
average number of interactions and the range of the low energy
electron as it thermalizes in these two mediums were obtained from
all the method types. The contribution of the DEA process for
electron attenuation in water is calculated as a function of
initial electron energy. There is a divide in the scientific
community as to the role and total contribution of this process to
water radiolysis products and the following chemical stage after
irradiation, particularly its role in the generation of excess
molecular hydrogen from water and water-oxide interfaces. The
percentage of secondary electrons generated at a specific initial
energy that terminate their radiation tracks as either a
thermalized electron, hydrated electron (or the precursor to e –
) or those that aq become captured in the DEA resonance is
calculated for the first time for the purpose to determine the
significance of this process. Finally, the effect of the coulomb
field from a sibling ionized water radical cation on a thermalizing
electron is the next step to understanding the thermalization of
the low energy electron in condensed water. This calculation opens
the door to simulations on the geminate recombination kinetics of
fully thermalized electrons. The dielectric constant of water is
taken at its high and low frequency limit to understand the effect
of the strength of the coulomb field…
Advisors/Committee Members: BURTON, NEIL NA, Pimblott, Simon, Burton, Neil.
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Smith, M. (2018). Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313044
Chicago Manual of Style (16th Edition):
Smith, Marisa. “Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water.” 2018. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313044.
MLA Handbook (7th Edition):
Smith, Marisa. “Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water.” 2018. Web. 19 Jan 2021.
Vancouver:
Smith M. Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313044.
Council of Science Editors:
Smith M. Computational Study of Low Energy Electrons Through
Amorphous Ice and Gaseous Phase Water. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:313044
University of Manchester
14.
Huerta, Monica.
Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems.
Degree: 2010, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:99633
► Experimental measurements in conjunction with stochastic simulations are used to determine hydrogen atom yields in the gamma and heavy ions radiolysis of aqueous solutions of…
(more)
▼ Experimental measurements in conjunction with
stochastic simulations are used to determine hydrogen atom yields
in the gamma and heavy ions radiolysis of aqueous solutions of
formate and deuterated formate ions.In radiolysis, the hydrogen
atom is produced directly by the fragmentation of water excited
states, and during the diffusion-kinetic evolution of the radiation
track by the intra-track reaction of eaq- with Haq+ up to the
microsecond timescale. The yield of H• is relatively small, but it
is fundamentally very important. An accurate examination of the H
atom yields after radiolysis will make possible a better
understanding of the initial steps of the radiolytic decomposition
of water. The competition between H atom combination reactions and
its formation by reaction of eaq- with Haq+ makes predictions of
the H atom kinetics very difficult. Hydrogen atom yields were
determined by difference measurements of H2 yields and
directmeasurements of HD yields when using deuterated formate as H•
scavenger. While the total H2 yield measured is always greater for
alpha than for gamma radiolysis, the H atom yield is observed to be
smaller. The addition of selected scavengers of the hydrated
electron and its precursors reveals a stronger correlation of the H
atom formation on the precursor to the hydrated electron rather
than the hydrated electron itself. Scavengable H• yields strongly
decrease as the concentration of the electron scavenger
increases.Stochastic track chemistry calculations were used to
analyze the measured experimental yields and to elucidate the
underlying kinetics.
Advisors/Committee Members: Pimblott, Simon.
Subjects/Keywords: Hydrogen; Radiolysis; Gamma; Heavy Ions
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APA (6th Edition):
Huerta, M. (2010). Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:99633
Chicago Manual of Style (16th Edition):
Huerta, Monica. “Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems.” 2010. Doctoral Dissertation, University of Manchester. Accessed January 19, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:99633.
MLA Handbook (7th Edition):
Huerta, Monica. “Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems.” 2010. Web. 19 Jan 2021.
Vancouver:
Huerta M. Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems. [Internet] [Doctoral dissertation]. University of Manchester; 2010. [cited 2021 Jan 19].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:99633.
Council of Science Editors:
Huerta M. Hydrogen atom formation in the gamma and heavy ion
radiolysis of aqueous systems. [Doctoral Dissertation]. University of Manchester; 2010. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:99633
. 
Open Access Theses and Dissertations
