Imperial College London

Professor WE (Bill) Lee FREng

Faculty of EngineeringInstitute for Security Science & Technology

Distinguished Research Fellow
 
 
 
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Contact

 

w.e.lee Website

 
 
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Assistant

 

Miss Eva Konstantara +44 (0)20 7594 8864

 
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Location

 

Abdus Salam LibrarySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

489 results found

Ghardi EM, Scrimshire A, Smith R, Bingham PA, Middleburgh SC, Lee WE, Rushton MJDet al., 2024, First-principles study of lithium aluminosilicate glass scintillators., Phys Chem Chem Phys, Vol: 26, Pages: 6138-6147

Radiation sensors are an important enabling technology in several fields, such as medicine, scientific research, energy, defence, meteorology, and homeland security. Glass-based scintillators have been in use for more than 50 years and offer many benefits, including their ability to respond to different types of radiation, and to be readily formed into various shapes. There is, however, the prospect to develop new and improved glass scintillators, with low self-absorption, low refractive indices, and high radiative recombination rates. To investigate the factors limiting the improvement of glass scintillator properties, this work provides insight from atomic scale simulations of the cerium-doped lithium aluminosilicate (SiO2-Al2O3-MgO-Li2O-Ce2O3) glass scintillator system. Three glass compositions were studied using molecular dynamics and density functional theory to investigate the effect of the ratio (with RAl/M = [0.1, 0.8 and 1.2]) on the structural and electronic properties. For a ratio RAl/M > 1, it has been shown that glasses with increased polymerization allow for more effective incorporation of Ce3+ cations. The structural analysis also showed that the bond order of Al-O can be affected in the presence of a lithium-rich environment. Electronic density of states and Bader charge analysis indicate a decline in the population of localized trapping states with increasing RAl/M. This suggests a higher probability of radiative recombination which can increase the photon yield of these scintillators. These findings provide valuable guidance for optimizing Li-glasses in neutron detection systems by highlighting the intricate challenges.

Journal article

Petkova E, Ciarleglio A, Casey P, Poole N, Kaufman K, Lawrie SM, Malhi G, Siddiqi N, Bhui K, Lee Wet al., 2024, Positive thinking about negative studies., Br J Psychiatry, Pages: 1-3

The non-reporting of negative studies results in a scientific record that is incomplete, one-sided and misleading. The consequences of this range from inappropriate initiation of further studies that might put participants at unnecessary risk to treatment guidelines that may be in error, thus compromising day-to-day clinical practice.

Journal article

Stephens GF, Owen MW, Ghardi EM, Fraile A, Ortner S, Rushton MJD, Lee WE, Cole-Baker A, Middleburgh SCet al., 2024, Assessing Li accommodation at amorphous ZrO<inf>2</inf> grain boundaries, Journal of Nuclear Materials, Vol: 588, ISSN: 0022-3115

Nuclear Pressurised Water Reactors (PWRs) use zirconium alloys as a fuel cladding, preventing the cooling water, at elevated pH using lithium hydroxide, from interacting with the fuel. Boron, as boric acid, is added to the coolant as a reactivity shim. Future reactor designs are considering removing soluble boron reactivity control to aid plant simplification. The presence of lithium in the absence of boron in the coolant has, however, been found to accelerate the corrosion of zirconium-based alloys under certain conditions and the mechanisms by which this occurs is under investigation. The ingress of lithium into the bulk oxide layer of zirconium alloy has been addressed in a previous study and was found to be unlikely. Here, atomistic simulations were used to produce Brouwer diagrams from which the solubility of lithium in amorphous structures representing complex grain boundaries have been predicted. The solubility of lithium in these amorphous structures is predicted to be high and will produce an elevated concentration of oxygen defects within the amorphous structure. This could offer a mode for transport of oxygen to the metal oxide interface and, potentially, offer a mechanism or part of a mechanism for observed lithium-accelerated corrosion of Zr-based alloys.

Journal article

Owen MW, Rushton MJD, Cooper MWD, Claisse A, Ghardi M, Lee WE, Middleburgh SCet al., 2023, Accommodation and Stability of Alloying Elements in Amorphous Grain Boundaries of Zirconia, Zirconium in the Nuclear Industry: 20th International Symposium, Publisher: ASTM International, Pages: 459-473, ISBN: 9780803177376

Book chapter

Owen MW, Rushton MJD, Cooper MWD, Ghardi EM, Claisse A, Lee WE, Middleburgh SCet al., 2023, Modelling the impact of configurational entropy on the stability of amorphous SiO2, SCRIPTA MATERIALIA, Vol: 233, ISSN: 1359-6462

Journal article

Gillett G, Westwood S, Thomson AB, Lee Wet al., 2023, 'Medical clearance' and referral to liaison psychiatry: a national service evaluation., BJPsych Bull, Pages: 1-8, ISSN: 2056-4694

AIMS AND METHOD: The prevalence of delaying psychiatric care until the patient has received 'medical clearance', and the definitions and understanding of 'medical clearance' terminology by relevant clinicians, are largely unknown. In a service evaluation of adult liaison psychiatry services across England, we explore the prevalence, definitions and understanding of 'medical clearance' terminology in three parallel studies: (a) an analysis of trust policies, (b) a survey of liaison psychiatry services and (c) a survey of referring junior doctors. Content and thematic analyses were performed. RESULTS: 'Medical clearance' terminology was used in the majority of trust policies, reported as a referral criterion by many liaison psychiatry services and had been encountered by most referring doctors. 'Medical clearance' was identified as a common barrier to liaison psychiatry referral. Terms were inconsistently used and poorly defined. CLINICAL IMPLICATIONS: Many liaison psychiatry services seem not to comply with guidance promoting parallel assessment. This may affect parity of physical and mental healthcare provision.

Journal article

Owen MW, Cooper MWD, Rushton MJD, Claisse A, Lee WE, Middleburgh SCet al., 2023, Diffusion in undoped and Cr-doped amorphous UO 2, JOURNAL OF NUCLEAR MATERIALS, Vol: 576, ISSN: 0022-3115

Journal article

Middleburgh SC, Dumbill S, Qaisar A, Vatter I, Owen M, Vallely S, Goddard D, Eaves D, Puide M, Limback M, Lee WEet al., 2023, Enrichment of Chromium at Grain Boundaries in Chromia Doped UO2, JOURNAL OF NUCLEAR MATERIALS, Vol: 575, ISSN: 0022-3115

Journal article

Hines D, Ford T, Westwood S, Barrett JR, Westphal B, Davies V, Lee Wet al., 2023, Evaluating the provision of paediatric liaison psychiatry services in England., BJPsych Open, Vol: 9, ISSN: 2056-4724

BACKGROUND: Liaison psychiatry provision for children and young people in England is poorly evaluated. AIMS: We sought to evaluate paediatric liaison psychiatry provision and develop recommendations to improve practice. METHOD: The liaison psychiatry surveys of England (LPSE) cross-sectional surveys engage all liaison psychiatry services in England. Services are systematically identified by contacting all acute hospitals with emergency departments in England. Questions are developed in consultation with NHS England and the Royal College of Psychiatrists' Faculty of Liaison Psychiatry, and updated based on feedback. Responses are submitted by email, post or telephone. Questions on paediatric services were included from 2015 (LPSE-2), and we analysed data from this and the subsequent four surveys. RESULTS: The number of acute hospitals with access to paediatric liaison psychiatry services increased from 29 (15.9%) in 2015 to 46 (26.6%) in 2019, compared with 100% provision for adults. For LPSE-4, only one site met the Core-24 criteria of 11 full-time equivalent mental health practitioners and 1.5 full-time equivalent consultants, and for LPSE-5, just two sites exceeded them. Acute hospitals with access to 24/7 paediatric liaison psychiatry services increased from 12 to 19% between LPSE-4 and LPSE-5. The proportion of paediatric liaison psychiatry services based offsite decreased from 30 to 24%. CONCLUSIONS: There is an unacceptable under-provision of paediatric liaison psychiatry services compared with provision for adults. Number of services, staffing levels and hours of operation have increased, but continued improvement is required, as few services meet the Core-24 criteria.

Journal article

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

Journal article

Owen MW, Rushton MJD, Cooper MWD, Claisse A, Ghardi M, Lee WE, Middleburgh SCet al., 2023, Accommodation and Stability of Alloying Elements in Amorphous Grain Boundaries of Zirconia, Pages: 459-473, ISSN: 0066-0558

A combination of modeling methods has been used to analyze the configurational entropy of undoped and doped amorphous and crystalline ZrO2 systems. In this work, chromia, Cr2O3, has been analyzed as a dopant in crystalline and amorphous zirconia currently at 10 at.% chromium and at a range of temperatures between 300 and 2,000 K. These systems have been modeled using a range of techniques, including molecular dynamics and density functional theory. Modifications to the structures upon introducing chromium is observed. For the first time, the entropy of the amorphous system is modeled and compared to the crystalline system. Amorphous undoped systems have higher configurational entropies owing to greater disorder observed compared with the crystalline counterpart. Dopants act to modify the original crystalline lattice, inducing.

Conference paper

Lin-Vines AX, Wilson JA, Fraile A, Evitts LJ, Rushton MJD, Astbury JO, Lee WE, Middleburgh SCet 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.

Journal article

Lee W, Casey P, Poole N, Kaufman KR, Lawrie SM, Malhi G, Petkova E, Siddiqi N, Bhui Ket al., 2022, The integrity of the research record: a mess so big and so deep and so tall., Br J Psychiatry, Vol: 221, Pages: 580-581

Poor research integrity is increasingly recognised as a serious problem in science. We outline some evidence for this claim and introduce the Royal College of Psychiatrists (RCPsych) journals' Research Integrity Group, which has been created to address this problem.

Journal article

Bolukbasi MJ, Middleburgh SC, Vrtiska S, Lee WEet al., 2022, Effect of ZrB2 and UB2 Discrete Burnable Absorber Pins on fuel reactivity, PROGRESS IN NUCLEAR ENERGY, Vol: 150, ISSN: 0149-1970

Journal article

Wilson JA, Evitts LJ, Fraile A, Wilson RE, Rushton MJD, Goddard DT, Lee WE, Middleburgh SCet 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

Journal article

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

Journal article

Moore CM, Wilson JA, Rushton MJD, Lee WE, Astbury JO, Middleburgh SCet al., 2022, Hydrogen accommodation in the TiZrNbHfTa high entropy alloy, ACTA MATERIALIA, Vol: 229, ISSN: 1359-6454

Journal article

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.

Conference paper

Mahalle G, Davis TP, Lee WE, Al Mamun Aet al., 2022, Investigation of strain-rate sensitivity of T91 Steel Using Small Punch Testing, Pages: 570-577

The Small Punch Test (SPT) is a useful technique for deriving location-dependent mechanical properties using small-sized specimens. In this work, we have investigated the tensile and fracture behavior of T91 steel, a candidate material for fusion and Gen IV fission nuclear reactors, by the SPT technique. Firstly, the hot shear flow behavior of T91 steel was investigated by SPT in the temperature range of 400-550 ºC under quasi-static strain rates (0.003 mm/min and 0.3 mm/min). Further, the hot deformation material parameters in the exponential power-law and hyperbolic sine constitutive equations have been evaluated. The effect of temperature and strain rate variation on stress exponent in power-law and activation energy from hyperbolic sine equation have been correlated.

Conference paper

Stephens GF, Than YR, Neilson W, Evitts LJ, Wenman MR, Murphy ST, Grimes RW, Cole-Baker A, Ortner S, Gotham N, Rushton MJD, Lee WE, Middleburgh SCet al., 2021, The accommodation of lithium in bulk ZrO<sub>2</sub>, SOLID STATE IONICS, Vol: 373, ISSN: 0167-2738

Journal article

Jayaseelan DD, Pramana S, Grasso S, Bai Y, Skinner S, Reece MJ, Lee WEet 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.

Journal article

Owen MW, Rushton MJD, Evitts LJ, Claisse A, Puide M, Lee WE, Middleburgh SCet al., 2021, Diffusion in doped and undoped amorphous zirconia, JOURNAL OF NUCLEAR MATERIALS, Vol: 555, ISSN: 0022-3115

Journal article

Zapata-Solvas E, Malmal Moshtaghioun B, Gomez-Garcia D, Dominguez-Rodriguez A, Lee WEet al., 2021, HfB<sub>2</sub> ceramic polycrystals: A low-temperature metal-like ceramic at high temperatures?, SCRIPTA MATERIALIA, Vol: 203, ISSN: 1359-6462

Journal article

Evitts LJ, Gilbert MR, Middleburgh SC, Lee WE, Dahlfors Met 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

Journal article

Bolukbasi MJ, Middleburgh SC, Dahlfors M, Lee WEet al., 2021, Performance and economic assessment of enriched gadolinia burnable absorbers, PROGRESS IN NUCLEAR ENERGY, Vol: 137, ISSN: 0149-1970

Journal article

Ji J, Zhang L, Yu J, Lee WE, Middleburgh SC, Li D, Wang X, Li Q, Wang Z, Shi G, Chen Fet al., 2021, Interface properties of Ti<sub>3</sub>SiC<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> ceramics: Combined experiments and first-principles calculations, CERAMICS INTERNATIONAL, Vol: 47, Pages: 6409-6417, ISSN: 0272-8842

Journal article

Fossati PCM, Mellan TA, Kuganathan N, Lee WEet al., 2021, Atomistic modeling approach to the thermodynamics of sodium silicate glasses, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Vol: 104, Pages: 1331-1344, ISSN: 0002-7820

Journal article

Middleburgh SC, Lee WE, Rushton MJD, 2021, Structure and properties of amorphous uranium dioxide, ACTA MATERIALIA, Vol: 202, Pages: 366-375, ISSN: 1359-6454

Journal article

Humphry-Baker SA, Ramanujam P, Smith GDW, Binner J, Lee WEet 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.

Journal article

Roumiguier L, Antou G, Pradeilles N, Jankowiak A, Zapata-Solvas E, Lee WE, Maitre Aet 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

Journal article

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