Browsing by Author "Obbard, EG"
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- ItemAnisotropy in the thermal expansion of uranium silicide measured by neutron diffraction(Elsevier, 2018-09) Obbard, EG; Johnson, KD; Burr, PA; Lopes, DA; Liss, KD; Griffiths, GJ; Scales, N; Middleburgh, SCIn-situ neutron diffraction patterns were collected for a sample of as-cast U3Si2 during heating to 1600 °C. Anomalous changes were observed above 1000 °C, including the formation of a new diffraction peak not belonging to P4/mbm U3Si2, unequal changes in the peak intensities and onset of anisotropic lattice expansion. The large data-set enabled derivation of a function-fitted isotropic thermal expansion coefficient to high precision, in close agreement with previous dilatometry results but reducing linearly with temperature over the studied interval. Anisotropy in the instantaneous lattice thermal expansion corresponded to anomalies reported by White et al. (2015) at a similar temperature. © Elsevier B.V
- ItemGamma radiation effects on the performance of FIR-based fiber-optic temperature sensors(Institute of Electrical and Electronics Engineers, 2019-11-02) Fan, D; Xiao, G; Chu, Y; Ma, Z; Wei, S; Zhang, B; Tian, Y; Fu, X; Obbard, EG; Davies, JB; Luo, Y; Peng, GDThe gamma radiation effect on the performance of fluorescence intensity ratio-based fiber-optic temperature sensors is studied. The results indicate such temperature sensors are promising for integration in gamma radiation environment.
- ItemIn-situ neutron characterization of advanced nuclear ruels - the road to a new neutron irradiation testing capability(The Minerals, Metals & Materials Society, 2020-02-23) Obbard, EG; Gasparrini, C; Burr, PA; Johnson, KD; Lopes, DA; Anghel, C; Middleburgh, SC; Gregg, DJ; Liss, KD; Griffiths, GJ; Scales, N; Thorogood, GJ; Lumprin, GRNot available.
- ItemA review on the development of nuclear power reactors(Elsevier, 2019-02) Ho, M; Obbard, EG; Burr, PA; Yeoh, GHNuclear power can solve the energy trilemma of supplying baseload, clean and affordable power. However, a review of nuclear power plant (NPP) builds show mixed results, with delays in Finland and in the US offset by successes in China, South Korea and the UAE. In the West, financing for new builds has been difficult in the face of a deregulated energy market, billion-dollar upfront investments, long build times and in the case of the US historically low gas prices. We explore how the nuclear industry is innovating in facing these challenges through a review of nuclear power developments in the past, present and future. Early developments in nuclear power in the 1950s resulted in a variety of designs, out of which the pressurised water reactor (PWR) became dominant for its compactness and overall economy. Over the next 10 years, several PWR-based small modular reactor (SMR) designs are expected to come online within an eight-year timeframe. Their modular construction and fabrication in a controlled factory setting aims to shorten build times from 8 to 3 years. However, the lack of established regulatory approval pathways may be a time-limiting challenge that needs to be overcome by the first fleet of SMRs. The passive safety and a smaller fuel loading of SMRs will allow them to be deployed at more potential sites, including brownfield replacements of old coal-fired power plants or power unconventional, remote or islanded grids. Some SMRs are also designed to load follow which will allow them to work harmoniously with intermittent renewables sources with the promise of an affordable, truly carbon-neutral grid. In the longer term, advanced nuclear reactors in the form of sodium cooled, molten salt cooled, and high temperature gas cooled reactors hold the promise of providing efficient electricity production, industrial heat for heavy industry as well as the generation of hydrogen for synthetic fuel. © 2019 The Author(s). Creative Commons Published by Elsevier Ltd.
- ItemThermal expansion and steam oxidation of uranium mononitride analysed via in situ neutron diffraction(Elsevier B. V., 2023-03) Liu, J; Gasparrini, C; White, JT; Johnson, KD; Lopes, DA; Peterson, VK; Studer, AJ; Griffiths, GJ; Lumpkin, GR; Wenman, MR; Burr, PA; Sooby, ES; Obbard, EGIn situ neutron powder diffraction experiments are applied to physical, kinetic, and microstructural characterization of uranium mononitride as a promising light water reactor fuel material. The temperature-variable coefficient of thermal expansion and isotropic Debye Waller factors are obtained by sequential Rietveld refinement over 499–1873 K. Oxidation of a UN pellet (95.2% density) under flow of 11 mg/min D2O is observed to initiate above 623 K and the rate increases by a factor of approximately 10 from 673 to 773 K, with activation energy 50.6 ± 1.3 kJ/mol; uranium oxide is the only solid corrosion product. Crown Copyright © 2022 Published by Elsevier B.V.
- ItemThermodynamic properties at the rim in high burnup UO2 fuels(The Minerals, Metals & Materials Society, 2020-02-23) Frost, D; Veliscek-Carolan, J; Galvin, C; Obbard, EG; Cooper, MWD; Burr, PANot available