Publications
462 results found
Makurunje P, Middleburgh SC, Lee WE, 2023, Addressing high processing temperatures in reactive melt infiltration for multiphase ceramic composites, Journal of the European Ceramic Society, Vol: 43, Pages: 183-197, ISSN: 0955-2219
Approaches for addressing the high processing temperatures required in reactive melt infiltration (RMI) processing of state-of-the-art multiphase ceramic matrix composites (CMCs) are reviewed. Ultra-high temperature ceramic composites can be realised by reactive melt infiltration of silicon, transition metals and/or alloys designed as immiscible phases, miscible phases, silicide phases and/or silicide eutectics to lower the temperature required for RMI. Whether carbides, borides or nitrides are envisaged in the resultant ceramic matrix composite, RMI presents an optimization challenge of balancing the composition of the phases incorporated and the processing temperature to be used. Current efforts aim at preparing complex and homogeneous microstructure preforms prior to RMI, minimising damage to reinforcing phases, applying rapid heating techniques, and developing in situ real-time monitoring systems during RMI. Future opportunities include integration of additive manufacturing and RMI, the increased use of process modelling and the application of in situ alongside in operando characterization techniques.
Lin-Vines AX, Wilson JA, Fraile A, et al., 2022, Defect behaviour in the MoNbTaVW high entropy alloy (HEA), Results in Materials, Vol: 15
The intrinsic defect formation in the MoNbTaVW HEA is investigated using atomic scale modelling, the goal being to assess its response to radiation damage in its possible use as plasma facing material for fusion reactors. When interstitial defects were modelled, a strong preference to form split interstitial defects containing vanadium was observed, even forming when other interstitial elements were initially placed into the structure. Vacancies and Frenkel pair formation are also modelled and discussed. The distinct behaviour of defects in this HEA has implications for this system as well as related HEAs and their use in nuclear components.
Bolukbasi MJ, Middleburgh SC, Vrtiska S, et al., 2022, Effect of ZrB2 and UB2 Discrete Burnable Absorber Pins on fuel reactivity, PROGRESS IN NUCLEAR ENERGY, Vol: 150, ISSN: 0149-1970
Wilson JA, Evitts LJ, Fraile A, et al., 2022, Predicting the thermal expansion of body-centred cubic (BCC) high entropy alloys in the Mo-Nb-Ta-Ti-W system, JOURNAL OF PHYSICS-ENERGY, Vol: 4, ISSN: 2515-7655
Quadling A, Lee WE, Astbury J, 2022, Materials challenges for successful roll-out of commercial fusion reactors, JOURNAL OF PHYSICS-ENERGY, Vol: 4, ISSN: 2515-7655
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- Citations: 1
Moore CM, Wilson JA, Rushton MJD, et al., 2022, Hydrogen accommodation in the TiZrNbHfTa high entropy alloy, ACTA MATERIALIA, Vol: 229, ISSN: 1359-6454
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- Citations: 2
Aamoth B, Lee WE, Ahmed H, 2022, Net-Zero Through Small Modular Reactors-Cybersecurity Considerations
In recent years, countries across the world have started developing small modular reactors (SMRs), nuclear reactors that generally produce around 300 megawatts of electricity (MWe). Many believe this type of reactor could be key in helping countries achieve their net-zero goals, as they are theoretically less expensive and safer than their larger counterparts, which usually produce more than 500 MWe. SMRs will be assembled in factories and operated in a mostly remote manner, raising concerns about cybersecurity. This paper attempts to analyze the cybersecurity of traditional nuclear reactors and the cyberphysical systems they rely on, analyze the novel ways in which SMRs will be developed and operated, and then highlight how and why SMRs could be particularly vulnerable to cyber-attacks. This paper finds that SMRs will be more susceptible to cyberattacks when compared to larger, more traditional reactors. Mitigations are offered that should increase the cyber-resilience of SMRs.
Jayaseelan DD, Pramana S, Grasso S, et al., 2021, Fabrication and characterisation of single-phase Hf2Al4C5 ceramics, Journal of the European Ceramic Society, Vol: 42, Pages: 1292-1301, ISSN: 0955-2219
Single-phase Hf2Al4C5 ternary carbide was fabricated from Hf/Al/C powder mixtures by pressure assisted sintering techniques such as hot pressing and spark plasma sintering at 1900 °C for 3 h and 10 min, respectively. XRD confirmed that the ternary carbide started to form at temperatures as low as 1500 °C and with total formation of Hf2Al4C5 after reactive sintering for 1 h at 1900 °C. It is evident from HRTEM that two Hf-C layers were sandwiched with 4 Al-C layers (Al4C3) in the Hf2Al4C5 ternary carbide. Tight interlocking of grains, faceted grains and stacking faults were occasionally observed. Thermal conductivity of Hf2Al4C5 is measured to be 14 w m−1k−1 from room temperature to 1300 °C. The oxidation studies carried out at 1300 °C for 3 h reveal that the oxidation layer thickness is around 220 μm and it contains microcracks closer to sample surface whereas the interface looks seamless without any cracking or spallation of the oxide layer.
Stephens GF, Than YR, Neilson W, et al., 2021, The accommodation of lithium in bulk ZrO2, SOLID STATE IONICS, Vol: 373, ISSN: 0167-2738
Owen MW, Rushton MJD, Evitts LJ, et al., 2021, Diffusion in doped and undoped amorphous zirconia, JOURNAL OF NUCLEAR MATERIALS, Vol: 555, ISSN: 0022-3115
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- Citations: 3
Zapata-Solvas E, Malmal Moshtaghioun B, Gomez-Garcia D, et al., 2021, HfB2 ceramic polycrystals: A low-temperature metal-like ceramic at high temperatures?, SCRIPTA MATERIALIA, Vol: 203, ISSN: 1359-6462
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- Citations: 1
Bolukbasi MJ, Middleburgh SC, Dahlfors M, et al., 2021, Performance and economic assessment of enriched gadolinia burnable absorbers, PROGRESS IN NUCLEAR ENERGY, Vol: 137, ISSN: 0149-1970
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- Citations: 1
Evitts LJ, Gilbert MR, Middleburgh SC, et al., 2021, Utilizing neutronics modelling to predict changing Pu ratios in UO2 in the presence of Th, PROGRESS IN NUCLEAR ENERGY, Vol: 137, ISSN: 0149-1970
Ji J, Zhang L, Yu J, et al., 2021, Interface properties of Ti3SiC2/Al2O3 ceramics: Combined experiments and first-principles calculations, CERAMICS INTERNATIONAL, Vol: 47, Pages: 6409-6417, ISSN: 0272-8842
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- Citations: 18
Middleburgh SC, Lee WE, Rushton MJD, 2021, Structure and properties of amorphous uranium dioxide, ACTA MATERIALIA, Vol: 202, Pages: 366-375, ISSN: 1359-6454
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- Citations: 8
Humphry-Baker SA, Ramanujam P, Smith GDW, et al., 2020, Ablation resistance of tungsten carbide cermets under extreme conditions, International Journal of Refractory Metals and Hard Materials, Vol: 93, ISSN: 0263-4368
A cobalt-free tungsten carbide cermet (WC-FeNi) has been subjected to oxyacetylene flame tests to simulate extreme operating conditions such as a worst-case fusion reactor accident. In such an accident, air-ingress to the reactor may impinge on components operating at surface temperatures in excess of 1000 °C, leading to tungsten oxide formation and its subsequent hazardous volatilisation. Here, the most challenging accident stage has been simulated, where the initial air-ingress could lead to extremely rapid air-flow rates. These conditions were simulated using an oxidising oxyacetylene flame. The separation between flame nozzle and sample was varied to permit peak surface temperatures of ~950–1400 °C. When the peak temperature was below 1300 °C, the cermet gained mass due to the dominance of oxide scale formation. Above 1300 °C, the samples transitioned into a mass loss regime. The mass loss regime was dominated by ablation of the scale rather than its volatilisation, which was confirmed by performing a systematic thermogravimetric kinetic analysis. The result was unexpected as in other candidate shielding materials, e.g. metallic tungsten, volatilisation is considered the primary dispersion mechanism. The unusual behaviour of the cermet scale is explained by its relatively low melting point and by the lower volatility of its FeWO4 scale compared to tungsten's WO3 scale. The substantially lower volatility of the WC cermet scale compared to metallic W indicates it may have a superior accident tolerance.
Fossati PCM, Mellan TA, Kuganathan N, et al., 2020, Atomistic modeling approach to the thermodynamics of sodium silicate glasses, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 104, Pages: 1331-1344, ISSN: 0002-7820
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- Citations: 2
Roumiguier L, Antou G, Pradeilles N, et al., 2020, Effect of powder purification by heat-treatment on the creep behaviour of dense boron carbide monoliths, JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, Vol: 40, Pages: 2253-2259, ISSN: 0955-2219
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- Citations: 1
Gasparrini C, Rana D-S, Le Brun N, et al., 2020, On the stoichiometry of zirconium carbide, Scientific Reports, Vol: 10, ISSN: 2045-2322
The dependencies of the enhanced thermomechanical properties of zirconium carbide (ZrCx) with sample purity and stoichiometry are still not understood due to discrepancies in the literature. Multiple researchers have recently reported a linear relation between the carbon to zirconium atomic ratio (C/Zr) and the lattice parameter, in contrast with a more established relationship that suggests that the lattice parameter value attains a maximum value at a C/Zr ~ 0.83. In this study, the relationship between C/Zr atomic ratio and the lattice parameter is critically assessed: it is found that recent studies reporting the thermophysical properties of ZrCx have unintentionally produced and characterised samples containing zirconium oxycarbide. To avoid such erroneous characterization of ZrCx thermophysical properties in the future, we propose a method for the accurate measurement of the stoichiometry of ZrCx using three independent experimental techniques, namely: elemental analysis, thermogravimetric analysis and nuclear magnetic resonance spectroscopy. Although a large scatter in the results (ΔC/Zr = 0.07) from these different techniques was found when used independently, when combining the techniques together consistent values of x in ZrCx were obtained.
Rana D-SBK, Solvas EZ, Lee WE, et al., 2020, An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures, SCIENTIFIC REPORTS, Vol: 10, ISSN: 2045-2322
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- Citations: 5
Middleburgh SC, Ipatova I, Evitts LJ, et al., 2020, Evidence of excess oxygen accommodation in yttria partially-stabilized zirconia, Scripta Materialia, Vol: 175, Pages: 7-10, ISSN: 1359-6462
Yttria partially stabilized zirconia (ZrO2)x(Y2O3)½-x has been investigated to understand accommodation of excess oxygen into its structure. ZrO2 powder with 8 wt% Y2O3 additions was treated in 30 vol% H2O2 solution to promote oxidation of the material. A new Raman peak was observed after treatment at 840 cm−1, consistent with previous reports of solid state peroxide ions (O22−). This was corroborated using atomic scale simulation based on density functional theory; these also highlighted the near-zero solution enthalpy for excess oxygen in the monoclinic structure via the formation of a peroxide ion defect.
Bowden D, Ward J, Middleburgh S, et al., 2020, The stability of irradiation-induced defects in Zr3AlC2, Nb4AlC3 and (Zr-0.5,Ti-0.5)(3)AlC2 MAX phase-based ceramics, ACTA MATERIALIA, Vol: 183, Pages: 24-35, ISSN: 1359-6454
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- Citations: 21
Evitts LJ, Middleburgh SC, Kardoulaki E, et al., 2020, Influence of boron isotope ratio on the thermal conductivity of uranium diboride (UB2) and zirconium diboride (ZrB2), JOURNAL OF NUCLEAR MATERIALS, Vol: 528, ISSN: 0022-3115
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- Citations: 14
Dahlfors M, Joannou J, Brummitt A, et al., 2020, The UK national thermal-hydraulics facility: Motivations, design and planning status, Pages: 2876-2886
A UK National Thermal-Hydraulics Facility (NTHF) dedicated to supporting new reactor and other relevant business is being developed, one of the purposes being to deliver on the government's carbon emission reduction commitments. The facility site is foreseen to be at Menai Science Park on the isle of Anglesey in North Wales, a region expected to see significant low carbon energy deployment in coming years. The UK NTHF is envisioned to cater for the needs of emerging nuclear in the UK - but also to serve as a hardware platform for international thermal-hydraulics research collaboration. Plans are to construct a platform capable of maintaining several test loops including support for the UK's on-going, conventional nuclear new build programme as well as Gen-IV systems and associated materials like molten salt and liquid metal coolant media. Motivations are given for NTHF expected capabilities and requirements, which form the basis for its current design and planning state.
Hsieh Y-H, Rushton MJD, Fossati PCM, et al., 2020, Thermal footprint of a geological disposal facility containing EURO-GANEX wasteforms, PROGRESS IN NUCLEAR ENERGY, Vol: 118, ISSN: 0149-1970
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- Citations: 5
Juthapakdeeprasert J, Diaz OG, Lerdprom W, et al., 2019, Reactions and emissivity of cerium oxide with phosphate binder coating on basic refractory brick, INTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Vol: 17, Pages: 668-676, ISSN: 1546-542X
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- Citations: 3
Al Nasiri N, Patra N, Pezoldt M, et al., 2019, Investigation of a single-layer EBC deposited on SiC/SiC CMCs: Processing and corrosion behaviour in high-temperature steam, Journal of the European Ceramic Society, Vol: 39, Pages: 2703-2711, ISSN: 0955-2219
Two rare earth monosilicates (Yb 2 SiO 5 , and Lu 2 SiO 5 ) were deposited using a low-cost coating application method to produce a single-layer coating. RE- oxides slurries were dip coated on oxidised CMC samples and subsequently heat treated at high temperature to ensure reaction between SiO 2 and RE-oxides to form the RE-monosilicate. A single, continuous, homogeneous thick coating of 25 μm was obtained. X-ray diffraction (XRD) confirmed formation of, RE-monosilicates in Yb and Lu silicate systems. Coated samples were exposed to 90% H 2 O static steam environment at 1350 °C for 25, 50, 100, and 150 h. Scanning Electron Microscopy (SEM) indicated that both coatings adhered strongly to the substrate. Coating thickness reduced from 22 μm to 11 μm for Yb-coating and 13 to 4 μm for Lu-coating with increasing corrosion time from 25 to 150 h, however there was no significant attack of the CMC for all steam exposure times.
Rushton MJD, Ipatova I, Evitts LJ, et al., 2019, Stoichiometry deviation in amorphous zirconium dioxide, RSC ADVANCES, Vol: 9, Pages: 16320-16327, ISSN: 2046-2069
Zhang H, Jayaseelan DD, Bogomol I, et al., 2019, A novel microstructural design to improve the oxidation resistance of ZrB2-SiC ultra-high temperature ceramics (UHTCs), JOURNAL OF ALLOYS AND COMPOUNDS, Vol: 785, Pages: 958-964, ISSN: 0925-8388
Gasparrini C, Podor R, Fiquet O, et al., 2019, Uranium carbide oxidation from 873 K to 1173 K, Corrosion Science, Vol: 151, Pages: 44-56, ISSN: 0010-938X
Oxidation of UC was studied from 873 to 1173 K in air and in 10 Pa oxygen using a High Temperature Environmental SEM (HT-ESEM). Conversion to U 3 O 8 improved when using 873 K as the oxide product was a fine powder. At higher temperatures (973 K to 1173 K) oxidation slowed due to a densification process with formation of coarse fragments. The oxide fragmentation at 973 K and 1073 K and oxide pulverisation at 873 K were observed in situ in a HT-ESEM. Cracking induced fragmentation and pulverisation was linked to stresses generated from the volumetric transformation from UC to U 3 O 8 .
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