Search

Your search keyword '"Bailey, Daniel J"' showing total 32 results
Start Over Author "Bailey, Daniel J"
32 results on '"Bailey, Daniel J"'

2. Clinical features and management of individuals admitted to hospital with monkeypox and associated complications across the UK: a retrospective cohort study

Author

Dunning, Jake, Fink, Douglas L, Milligan, Iain D, Luintel, Akish, Rodger, Alison J, Bhagani, Sanjay R, Lamb, Lucy E, Moores, Rachel C, Lee, Simon F K, Brown, Colin S, Hopkins, Susan, Mepham, Stephen, Warren, Simon, Molloy, Aoife, Cropley, Ian, Kew, Alex, Karunaharan, Natasha, Scobie, Antonia, Hart, Jennifer, Irish, Dianne, Haque, Tanzina, Jalal, Hamid, Smith, Robin, Mack, Damien, Barber, Tristan, Burns, Fiona, Miller, Robert, Hamlyn, Eleanor, Simoes, Pedro, Athan, Breda, Abrahamsen, Jennifer, Joyce, Jessica, Taylor, Caroline, Reddecliffe, Sally, Miller, Chloe, Reeve, Brooke, Kingston, Hugh, Crocker-Buque, Tim, Massie, Nicolas, Dhariwal, Ankush, Jayakumar, Angelina, Hammond, Robert, Bramley, Alexandra, Kanitkar, Tanmay, Maynard-Smith, Laura, Gil, Eliza, O'Connor, Cavan, Cocker, Derek, Spicer, Wendy, Lanzman, Marisa, Thacker, Meera, Anorson, Zoe O, Patel, Dharmesh, Williams, Alan, Houlihan, Catherine F, Wakerley, Dominic, Gordon, Claire N, Callaby, Helen, Bailey, Daniel J, Furneaux, Jenna, Bown, Abbie M, Truelove, Elizabeth J, Killip, Marian J, Jackson, David, Beetar-King, Tracy L B, Arnold, Ulrike M V, Strachan, Rhea M, Matthew, Jones, Matthew, Hannah J, Osborne, Jane C, Rampling, Tommy, Vipond, Richard, Gibney, Barry, Owen, Jodie, Bond, Helena, Beynon, Will, Hunter, Michael, McCorry, Louise, Emerson, Carol, Quah, Say, Todd, Suzanne, McCarty, Emma, Walker, Eoin, Feeney, Susan, Curran, Tanya, Li, Kathy, Mullan, JD, Jackson, Kate, Nelson, Peter, Lewis, Kevin, McNicol, Mark, Pratt, Marcus, Smith, Anna, Vos, Erin, Alsalemee, Fahad, O Leary, Daniel, Canny, John, McGinnity, Katherine, Culbert, Carly, McDowell, Conor, McQuillan, Cathy, Jeong, Eunjin, Glass, Lynsey, Dyche, Jessica, McClean, Paula, Stewart, Rebecca, Ursolino, Harold, Perry, Melissa, McCormick, Hannah, Lim, Eleanor Y, Gkrania-Klotsas, Effrossyni, Bracchi, Margherita, Heskin, Joseph, Brown, Nicklas, Juniper, Thomas, Mora-Peris, Borja, Dalla-Pria, Alessia, Mackie, Nicola, Garvey, Lucy, Winston, Alan, Cooke, Graham, Nelson, Mark, Kilbride, Emer, Elbishi, Ala, Kerrigan, William, Silva, Joshua, Gohil, Jesal, Payagala, Sasha, Walters, Yasmin, Smith, Joanna, Goodfellow, Jonathan, Lyons, Kitty, Tung, Hsiu, Patel, Kinjal, Henderson, Merle, Butler, Michael, Peres, Edu, Silva Carvalho, Taiana, Joly, Antoine, Dickinson, Molly, Moore, Luke S P, Mughal, Nabeela, Hughes, Stephen, Chitlangia, Shrada, Viramgana, Priyanka, Byrne, Ruth, Randell, Paul, Strangis, Luigi, Poveda, Nicola, Bovey, Deborah, Richardson, Poppy, Heaslip, Vivian, Higgs, Christopher, Boffito, Marta, Girometti, Nicolo, Whitlock, Gary, Tittle, Victoria, Jones, Rachel, Rayment, Michael, Scott, Christopher, Asboe, David, Pond, Marcus, Muir, David, Rathish, Balram, O'Hara, Geraldine, Abeywickrema, Movin, Bailey, Sarah-Lou, Boyd, Sara E, Da Silva Fontoura, Dayana, Daunt, Anna, Mason, Claire Y, Murphy, Jamie, Naidu, Vasanth V, Patel, Aatish, Pley, Caitlin, Redmore, Ethan, Sharrocks, Katherine, Snell, Luke B, Sundramoorthi, Rohan, Tam, Jerry C H, Brown, Aisling, Douthwaite, Sam, Goodman, Anna, Nebbia, Gaia, Newsholme, William, Price, Nicholas, Shaw, Emily, Salam, Alex, van Nispen tot Pannerden, Claire, Winslow, Helen, Bilinska, Julia, Keegan, Sarah, Coleman, Harry, Doctor, Jessica, Moini, Nasreen, Chilton, Daniella, Haidari, Golaleh, Simons, Rebecca, Kulasegaram, Rajababu, Larbalestier, Nick, Nori, Achyuta, Potter, Jack R, Tuudah, Cecilia, Wade, Paul, Travers, Alexandra, Dunford, Sarah, Greenwood, Joshua, Oledimmah, Georgina, Gyampo, Lesley, SA Pinto, Pedro, Muse, AbdulKadir, Parker, Zoe, Alexander, Charlotte, Khan, Alexander, Ajayi, Medinat, Baltazar, Abigail, Sharella, Davis, Hersi, Nasra, Nguyen, Thuy, Timbo, Rugiatu, Jalloh, Ismail, Bryan, Susan, Clarke, Patricia, Kerr, Marcia, Amedu, Fidelis, BohoBonaba, Maria, Haque, Sarah, Howson, Michelle, Tambilawan, Norbai, Yupanqui Estay, Soledad, Bangura, Hawanatu, Gideon, Tseday, Jerome-oboh, Damilola, Tetteh, Linda, Nwagu, Chioma, Agbaglah, Viwoalo, Narag, Nona, Zaveri, Mahima, Ni Luanaigh, Maedhbh, Keane, Peggy, Peters, Joanna R, Rimmer, Stephanie, Abbara, Aula, Dosekun, Olamide, Bolland, Mhairi, Stafford, Adam, Saleh, Dina, Sheridan, Rhianna, Davies, Ella, Sun, Kristi, Gilchrist, Mark, Kukadia, Priti, Embrahimsa, Muhammed, Chiu, Christopher, Taylor, Lauren, Short, Charlotte, Alagratnam, Jasmini, Jayaweera, Iresh, Gundugola, Kavitha, Payne, Lara V S, Mody, Nisha, Quinn, Killian, Nic Fhogartaigh, Caoimhe, Kaur, Nivenjit, Bholah, Salmaan, Kantha, Kajann, Youngs, Jonathan, Lampejo, Temi, Pitto, Nicholas, Lawrence, David S, Middleditch, Holly, Dominguez-Dominguez, Lourdes, Ratnappuli, Ayoma, Al-Hashimi, Sara, Oliveira, Amelia, Ottaway, Zoe, Mulka, Larissa, Hodgson, Bethany, Lewthwaite, Penny, Neary, Anne M, Downey, Michael R, Lucy, Danielle C, McCallum, Craig I, Beadsworth, Michael, Ratcliffe, Libuse, Fletcher, Tom E, Davies, Gerry, Wong, Nicholas, Aston, Stephen, Wingfield, Thomas E, Blanchard, Thomas, Hine, Paul, Lester, Rebecca, Woolley, Stephen D, Gould, Susie, Smith, Christopher, Abouyannis, Michael, Atomode, Abolaji, Cruise, James, Samual, Merna, Scott, Nicola, Srirathan, Vino, Lewis, Joseph, Richards, Lauren, Cummings, Mary-Ann, Gillan, Emily, Peers, Rebecca, Tickle, Amy, Keating, Grace, Chinyanda, Tendi, Sanchez, Mav, Harrison, Daniel, Hoyle, Metcalfe, Ben, Taylor, Jennifer, Johnson, Nicky, Kelle, Neil, McDowell, Kirsty, Richardson, Ian, Saguidan, Monette, Farmer, Nicky, Gillespie, Angella, Willoughby, Shay, Parker, Samantha, Avulan, Shamseena, Arif, Shazia, Marshall, Suzanne, Carlisle, David, Rezaei, Mohsen, Booth, Angela, Watts, Joanne, Tremarco, Lauren, Jeyanayagam, Priyanga, Ubochi, Odinaka, Vagianos, Daniel, Richardson, Mark, Jarvis, Anthony, Gow, Kyra, Walmsley, Jade, O'keefe, Adam, Smielewska, Anna, Hopkins, Mark, Balane, Fatima, Bradley, Sarah, Corrah, Tumena, Daquiz, Venus, Dugan, Christopher, Elliot, Joshua, Foley, Fiona, Friday, Dawn, Gamit, May, Garner, David, Gokani, Karishma, John, Laurence, Joseph, Deepa, Khan, Nuzhath, Mamuyac, Cherifer, McGregor, Alastair, McSorley, John, Parris, Victoria, Rubinstein, Luciana, Rycroft, Julian, Salinas, Kelcy, Salinas, Jason, Sebatian, Jency, Smith, Melanie, Tejero Garcia, Marina, Ume, Uchenna, Vicentine, Margarete, Wallis, Gabriel, Sturdy, Ann, Whittington, Ashley, Jacobs, Nathan, Johnson, Leann, Bonington, Alec, Uriel, Alison, Ustianowski, Andrew, Dancso, Balazs, Hogan, Celia, van Halsema, Clare, Vilar, F Javier, Devine, Karen, Ajdukiewicz, Katherine, Rajendran, Rajesh, Ghosh, Samit, Riste, Michael, Machin, Nicholas, Babu, Chitra, Ahmad, Shazaad, Obeng, Dorcas, Dave, Farnaz, Conolley, Gavin, Thompson, Joseph, Tickell-Painter, Maya, Chakravorty, Prasun, Pringle, Rachel, Zafar, Mohammad R, Lawrence, Sarah, Sanchez-Gonzalez, Amada, Fernandez, Cristina, Goodwin, Lynsey, Carey, David, Howarth-Maddison, Molly, Moody, Samuel, Upton, Rebecca, Apthorp, Christina, Murray, Charlotte, Salthouse, Kirstie, Nadeem, Sabah, Ridley, Grant, White, Francesca, Brown, Andrew, Lawless, Michael, Mohamed, Mohamed, Mulligan, Robert, Belfield, Amy, Brolly, Jacob, Calderon, Maria, Cheveau, James, Cullinan, Milo, Garrad, Sophie, Griffiths, Will, Ireland, Aidan, Ireland, Peter, Milne, Charlotte, Nwajiugo, Paul, Quartey, John, Ghavami-Kia, Bijan, Duncan, Chris, Evans, Adam, Hunter, Ewan, Price, Ashley, Schmid, Matthias, Schwab, Uli, Taha, Yusri, Payne, Brendan, Elliott, Ivo A M, Crowe, Stewart, Woodrow, Charles J, Karageorgopoulos, Drosos E, Davis, Peter J, Lord, Emily, Bannister, Oliver J, Dagens, Andrew B, Harrison, Thomas, Cole, Joby, Tunbridge, Anne, Choudry, Saher, Telfer, Adam, Jhibril, Ihsan, Atta, Syed N, Stone, Ben, Evans, Cariad, Ankcorn, Mike, Akili, Suha, Yavuz, Mehmet, Goodall, Vicky, Farrow, Sam, Mountford, Georgina, Cusack, Tomas-Paul, Beard, Kate, Sutton, Julian, Clark, Tristan, Mason, Annette, Vickers, Mike, Macallan, Derek, Bicanic, Tihana, Houston, Angela, Pope, Cassie, Tan, NgeeKeong, Ward, Christopher, Jones, Imogen, Banerjee, Rishi, Cohen, Jonathan, Emonts-le Clercq, Marieke, Porter, David, Riordan, Andrew, Sinha, Ruchi, Whittaker, Elizabeth, Beynon, William, Heskin, Jospeh, Milligan, Iain, Payne, Lara, AI Payne, Brendan, Elliott, Ivo AM, and Beard, Katie

Published
2023
Full Text
View/download PDF

3. Ceramic wasteforms for wastes arising from potential future fuel cycles

Author

Bailey, Daniel J., Hyatt, Neil C., and Stennett, Martin C.

Subjects
620
Abstract

The UK produces considerable volumes of radioactive materials as a result of nuclear power generation and subsequent reprocessing of spent nuclear fuel. Spent fuel is currently reprocessed using the PUREX process and the subsequent High Level Waste is immobilised in a borosilicate glass matrix, however, some elements present in the waste complicate the vitrification process either through volatilisation or the formation of undesirable secondary products. Proposed future fuel cycles offer the opportunity for enhanced segregation of wastes and therefore open up the possibility of more tailored disposal routes such as immobilisation in ceramic matrices. This thesis presents a series of studies on the immobilisation of problematic elements by the use of ceramic matrices. The wastes selected were: caesium, iodine, technetium, plutonium and Mixed Oxide Fuel residues. A summary of the main results for each waste are provided below: Caesium- The titanate phase hollandite was selected as the host matrix of choice for this study. A range of Cs containing iron hollandites were synthesised via an alkoxide-nitrate route and the structural environment of Fe in the resultant material characterised by Mössbauer and X-ray Absorption Near Edge Spectroscopy. The results of spectroscopic analysis found that Fe was present as octahedrally co-ordinated Fe (III) in all cases and acts as an effective charge compensator over a wide solid solution range. Iodine- Iodine immobilisation in the apatite structured iodovanadinite phase was studied using hot isostatic pressing (HIPing) to minimise iodine volatilisation. Increasing the overpressure during HIPing was found to yield products of superior density. The use of AgI as an iodine source was found to complicate the formation of the apatite phase and when used as the sole source was found to not be incorporated into the target phase at all. The possibility of co-immobilisation of Tc was investigated by using the surrogate molybdenum. Limited substitution of Mo into the apatite structure was observed however, this observation is complicated by the aforementioned non-incorporation of AgI. Further investigation is necessary to investigate the possibility of Mo incorporation when not using AgI as the iodine source. Substitution of Ba into the structure resulted in the formation of Ba3(VO4)2 structured phase with solid-solution behaviour observed between Ba and Pb. Mixed Oxide Fuel residues- Brannerite was selected as the potential host matrix for the disposal of MOX residues due to its high potential waste loading. Ce was used as an inactive structural surrogate for plutonium. The resultant phase assemblage was found to be dependent on both processing atmosphere and waste loading. In air, it was found that decreasing waste loading by substituting the neutron absorber gadolinium improved the phase assemblage. Reacting brannerites in a reducing atmosphere was found to produce a highly unfavourable phase assemblage with large amounts of retained UO2. The most favourable phase assemblage was found to be achieved by sintering in argon however, increasing substitution of Gd was found to have a negative impact. XANES study found that Ti oxidation state remained unchanged whereas Ce was found to reduce from the +4 to the +3 oxidation state in all cases. The use of μ-focus XANES confirmed that charge compensation was achieved by the oxidation of U(IV) to higher oxidation states. Technetium and plutonium- Zirconolite was selected as a potential host phase for the co-disposal of technetium and plutonium and studied using the non-active surrogates Ce and Mo. The formation of the zirconolite phase was found to be improved by reaction at higher temperatures and the use of CaTiO3 as the Ca precursor instead of CaCO3. Cold pressed and sintered zirconolites were found to be highly porous and this was attributed to the volatilisation of Mo at elevated temperatures. Hot isostatic pressing was found to improve the density of synthesised zirconolites however, the temperature limitations imposed by the use of stainless steel cans resulted in an unfavourable phase assemblage. HIPing for a longer period of time may compensate for the reaction kinetics or HIPing in an alternative can material at a higher temperature.

Published
2017

5. List of contributors

Author

Bailey, Daniel J., primary, Benzaazoua, Mostafa, additional, Biakhmetov, Bauyrzhan, additional, Cetin, Bora, additional, Charlet, Laurent, additional, Chatain, Vincent, additional, Chen, Jing, additional, Chen, Liang, additional, Chen, Meiqi, additional, Couvidat, Julien, additional, Darricau, Louise, additional, De Gisi, Sabino, additional, Dostiyarov, Abay, additional, Du, Yan-Jun, additional, El Khessaimi, Yassine, additional, Elghali, Abdellatif, additional, Fang, Zhuoting, additional, Fernandez-Martinez, Alejandro, additional, Gardner, Laura J., additional, Geddes, Daniel A., additional, Gowthaman, Sivakumar, additional, Guo, Binglin, additional, Hakkou, Rachid, additional, Hanein, Theodore, additional, Hedin, Niklas, additional, Hossain, Md. Uzzal, additional, Hu, Qing, additional, Huang, Jizhi, additional, Hyatt, Neil C., additional, Jiang, Ning-Jun, additional, Jin, Fei, additional, Jouini, Marouen, additional, Kawasaki, Satoru, additional, Kearney, Sarah, additional, Komatsu, Shin, additional, Labianca, Claudia, additional, Li, Jiangshan, additional, Li, Wengui, additional, Ling, Tung-Chai, additional, Liu, Yue, additional, Lyubartsev, Alexander, additional, Ma, Bin, additional, Ma, Zengyi, additional, Ma, Zhiming, additional, Mabroum, Safaa, additional, Mahedi, Masrur, additional, Mo, Kim Hung, additional, Mwandira, Wilson, additional, Nakashima, Kazunori, additional, Neculita, Carmen Mihaela, additional, Nelson, Shaun, additional, Ng, S. Thomas, additional, Notarnicola, Michele, additional, Pham, Phuong Ngoc, additional, Poon, Chi-Sun, additional, Provis, John L., additional, Qi, Yutong, additional, Qian, Yuandong, additional, Ren, Pengfei, additional, Ruan, Shaoqin, additional, Sasaki, Keiko, additional, Shen, Zhengtao, additional, Sun, Shi-Kuan, additional, Taha, Yassine, additional, Tan, Shengheng, additional, Tang, Pei, additional, Tang, Zhuo, additional, Tian, Quanzhi, additional, Todaro, Francesco, additional, Tong, Lizhi, additional, Tsang, Daniel C.W., additional, Walkley, Brant, additional, Wang, Fei, additional, Wang, Lei, additional, Wang, Linling, additional, Wang, Xin, additional, Xiao, Jianzhuang, additional, Xiong, Xinni, additional, Xu, Weiting, additional, Yan, Jianhua, additional, Yang, Jinqin, additional, Yorkshire, Antonia S., additional, You, Siming, additional, Zhang, Yike, additional, Zhang, Yunhui, additional, Zhang, Yuying, additional, Zhao, Nannan, additional, Zhong, Pucheng, additional, Zhou, Yifan, additional, and Zhuge, Yan, additional

Published
2022
Full Text
View/download PDF

10. An Investigation of Iodovanadinite Wasteforms for the Immobilisation of Radio-Iodine and Technetium.

Author

Bailey, Daniel J., Johnstone, Erik V., Stennett, Martin C., Corkhill, Claire L., and Hyatt, Neil C.

Subjects
ISOSTATIC pressing, TECHNETIUM, HOT pressing, IODINE, FISSION products, SCANNING electron microscopy
Abstract

99Tc and 129I are two long-lived, highly soluble and mobile fission products that pose a long-term hazard. A proposed wasteform for the disposal of radio-iodine is iodovanadinite (Pb5(VO4)3I), an apatite-structured vanadate. In this investigation, a suite of potential iodovanadinite wasteforms designed for the co-disposal of Tc and I or the sole disposal of I were synthesised via hot isostatic pressing (with Mo as a surrogate for Tc). It was found that direct synthesis from oxide and iodide precursors was possible using hot isostatic pressing (HIPing). Increasing overpressure during HIPing was found to improve the density of the final product. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses indicated that the use of AgI as the source of iodine affected the formation of the target iodovanadinite phase and produced unfavourable phase assemblages. Here, we report the direct synthesis of Pb5(VO4)3I in a single step by hot isostatic pressing. [ABSTRACT FROM AUTHOR]

Published
2023
Full Text
View/download PDF

19. Immobilizing Pertechnetate in Ettringite via Sulfate Substitution

Author

Saslow, Sarah A., primary, Kerisit, Sebastien N., additional, Varga, Tamas, additional, Mergelsberg, Sebastian T., additional, Corkhill, Claire L., additional, Snyder, Michelle M. V., additional, Avalos, Nancy M., additional, Yorkshire, Antonia S., additional, Bailey, Daniel J., additional, Crum, Jarrod, additional, and Asmussen, R. Matthew, additional

Published
2020
Full Text
View/download PDF

20. Spectroscopic evaluation of UVI–cement mineral interactions: ettringite and hydrotalcite.

Author

Yorkshire, Antonia S., Stennett, Martin C., Walkley, Brant, O'Sullivan, Sarah E., Mottram, Lucy M., Bailey, Daniel J., Provis, John L., Hyatt, Neil C., and Corkhill, Claire L.

Subjects
FLY ash, ETTRINGITE, HYDROTALCITE, MAGIC angle spinning, ACTINIDE elements, NUCLEAR magnetic resonance
Abstract

Portland cement based grouts used for radioactive waste immobilization contain high replacement levels of supplementary cementitious materials, including blast‐furnace slag and fly ash. The minerals formed upon hydration of these cements may have capacity for binding actinide elements present in radioactive waste. In this work, the minerals ettringite (Ca6Al2(SO4)3(OH)12·26H2O) and hydrotalcite (Mg6Al2(OH)16CO3·4H2O) were selected to investigate the importance of minor cement hydrate phases in sequestering and immobilizing UVI from radioactive waste streams. U LIII‐edge X‐ray absorption spectroscopy (XAS) was used to probe the UVI coordination environment in contact with these minerals. For the first time, solid‐state 27Al magic angle spinning nuclear magnetic resonance (MAS‐NMR) spectroscopy was applied to probe the Al coordination environment in these UVI‐contacted minerals and make inferences on the UVI coordination, in conjunction with the X‐ray spectroscopy analyses. The U LIII‐edge XAS analysis of the UVI‐contacted ettringite phases found them to be similar (>∼70%) to the uranyl oxyhydroxides present in a mixed becquerelite/metaschoepite mineral. Fitting of the EXAFS region, in combination with 27Al NMR analysis, indicated that a disordered Ca‐ or Al‐bearing UVI secondary phase also formed. For the UVI‐contacted hydrotalcite phases, the XAS and 27Al NMR data were interpreted as being similar to uranyl carbonate, that was likely Mg‐containing. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

24. Contribution of energetically reactive surface features to the dissolution of CeO2 and ThO2 analogues for spent nuclear fuel microstructures

Author

Corkhill, Claire L., Myllykyla, Emmi, Bailey, Daniel J., Thornber, Stephanie M., Qi, Jiahui, Maldonado, Pablo, Stennett, Martin C., Hamilton, Andrea, and Hyatt, Neil C.

Subjects
TP, TA, TK, QE, TS
Abstract

In the safety case for the geological disposal of nuclear waste, the release of radioactivity from the repository is controlled by the dissolution of the spent fuel in groundwater. There remain several uncertainties associated with understanding spent fuel dissolution, including the contribution of energetically reactive surface sites to the dissolution rate. In this study, we investigate how surface features influence the dissolution rate of synthesised CeO2 and ThO2, spent nuclear fuel analogues which approximate as closely as possible the mineral structure characteristics of fuel-grade UO2 but are not sensitive to changes in oxidation state of the cation. The morphology of grain boundaries (natural features) and surface facets (specimen preparation-induced features) were investigated during dissolution. The effects of surface polishing on dissolution rate was also investigated. We show that preferential dissolution occurs at grain boundaries, resulting in grain boundary decohesion and enhanced dissolution rates. A strong crystallographic control was exerted, with high misorientation angle grain boundaries retreating more rapidly than those with low misorientation angles, which may be due to the accommodation of defects in the grain boundary structure. The data from these simplified analogue systems support the hypothesis that grain boundaries play a role in the so-called "instant release fraction" of spent fuel, and should be carefully considered, in conjunction with other chemical effects, in safety performance assessements for the geological disposal of spent fuel. Surface facets formed during the sample annealing process also exhibited a strong crystallographic control and were found to dissolve rapidly on initial contact with dissolution medium. Defects and strain induced during sample polishing caused an overestimation of the dissolution rate, by up to 3 orders of magnitude.

Published
2014

27. Role of Microstructure and Surface Defects on the Dissolution Kinetics of CeO2, a UO2Fuel Analogue

Author

Corkhill, Claire L., Bailey, Daniel J., Tocino, Florent Y., Stennett, Martin C., Miller, James A., Provis, John L., Travis, Karl P., and Hyatt, Neil C.

Abstract

The release of radionuclides from spent fuel in a geological disposal facility is controlled by the surface mediated dissolution of UO2in groundwater. In this study we investigate the influence of reactive surface sites on the dissolution of a synthesized CeO2analogue for UO2fuel. Dissolution was performed on the following: CeO2annealed at high temperature, which eliminated intrinsic surface defects (point defects and dislocations); CeO2-xannealed in inert and reducing atmospheres to induce oxygen vacancy defects and on crushed CeO2particles of different size fractions. BET surface area measurements were used as an indicator of reactive surface site concentration. Cerium stoichiometry, determined using X-ray Photoelectron Spectroscopy (XPS) and supported by X-ray Diffraction (XRD) analysis, was used to determine oxygen vacancy concentration. Upon dissolution in nitric acid medium at 90 °C, a quantifiable relationship was established between the concentration of high energy surface sites and CeO2dissolution rate; the greater the proportion of intrinsic defects and oxygen vacancies, the higher the dissolution rate. Dissolution of oxygen vacancy-containing CeO2-xgave rise to rates that were an order of magnitude greater than for CeO2with fewer oxygen vacancies. While enhanced solubility of Ce3+influenced the dissolution, it was shown that replacement of vacancy sites by oxygen significantly affected the dissolution mechanism due to changes in the lattice volume and strain upon dissolution and concurrent grain boundary decohesion. These results highlight the significant influence of defect sites and grain boundaries on the dissolution kinetics of UO2fuel analogues and reduce uncertainty in the long term performance of spent fuel in geological disposal.

Published
2016
Full Text
View/download PDF

28. Contribution of Energetically Reactive Surface Features to the Dissolution of CeO2and ThO2Analogues for Spent Nuclear Fuel Microstructures

Author

Corkhill, Claire L., Myllykylä, Emmi, Bailey, Daniel J., Thornber, Stephanie M., Qi, Jiahui, Maldonado, Pablo, Stennett, Martin C., Hamilton, Andrea, and Hyatt, Neil C.

Abstract

In the safety case for the geological disposal of nuclear waste, the release of radioactivity from the repository is controlled by the dissolution of the spent fuel in groundwater. There remain several uncertainties associated with understanding spent fuel dissolution, including the contribution of energetically reactive surface sites to the dissolution rate. In this study, we investigate how surface features influence the dissolution rate of synthetic CeO2and ThO2, spent nuclear fuel analogues that approximate as closely as possible the microstructure characteristics of fuel-grade UO2but are not sensitive to changes in oxidation state of the cation. The morphology of grain boundaries (natural features) and surface facets (specimen preparation-induced features) was investigated during dissolution. The effects of surface polishing on dissolution rate were also investigated. We show that preferential dissolution occurs at grain boundaries, resulting in grain boundary decohesion and enhanced dissolution rates. A strong crystallographic control was exerted, with high misorientation angle grain boundaries retreating more rapidly than those with low misorientation angles, which may be due to the accommodation of defects in the grain boundary structure. The data from these simplified analogue systems support the hypothesis that grain boundaries play a role in the so-called “instant release fraction” of spent fuel, and should be carefully considered, in conjunction with other chemical effects, in safety performance assessements for the geological disposal of spent fuel. Surface facets formed during the sample annealing process also exhibited a strong crystallographic control and were found to dissolve rapidly on initial contact with dissolution medium. Defects and strain induced during sample polishing caused an overestimation of the dissolution rate, by up to 3 orders of magnitude.

Published
2014
Full Text
View/download PDF

30. A feasibility investigation of speciation by Fe K-edge XANES using a laboratory X-ray absorption spectrometer.

Author

MOTTRAM, Lucy M., CAFFERKEY, Samuel, MASON, Amber R., OULTON, Tom, SUN, Shi Kuan, BAILEY, Daniel J., STENNETT, Martin C., and HYATT, Neil C.

Subjects
*X-ray spectrometers, *CHEMICAL speciation, *ELECTRON configuration, *X-ray tubes, *OXIDATION states
Abstract

We demonstrate effective speciation of Fe in model compounds from analysis of the weak pre-edge features in Fe K-edge XANES spectra, with a commercially available laboratory X-ray spectrometer, using a spherically bent crystal analyser and a low-power X-ray tube, in Rowland circle geometry. Direct comparison with XANES data acquired from a third generation synchrotron bending magnet beamline, using the same specimens, validated quantitative agreement in determination of the total integrated intensity and centroid position of the pre-edge feature, which are a probe of the electronic configuration and symmetry of the absorber atom, and hence oxidation state and co-ordination number. This work opens the door to rapid and routine speciation studies of Fe by laboratory XANES, even for materials with relatively dilute absorber concentration of only a few mol. %. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

31. Spectroscopic evaluation of U VI -cement mineral interactions: ettringite and hydrotalcite.

Author

Yorkshire AS, Stennett MC, Walkley B, O'Sullivan SE, Mottram LM, Bailey DJ, Provis JL, Hyatt NC, and Corkhill CL

Abstract

Portland cement based grouts used for radioactive waste immobilization contain high replacement levels of supplementary cementitious materials, including blast-furnace slag and fly ash. The minerals formed upon hydration of these cements may have capacity for binding actinide elements present in radioactive waste. In this work, the minerals ettringite (Ca 6 Al 2 (SO 4 ) 3 (OH) 12 ·26H 2 O) and hydrotalcite (Mg 6 Al 2 (OH) 16 CO 3 ·4H 2 O) were selected to investigate the importance of minor cement hydrate phases in sequestering and immobilizing U VI from radioactive waste streams. U L III -edge X-ray absorption spectroscopy (XAS) was used to probe the U VI coordination environment in contact with these minerals. For the first time, solid-state 27 Al magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy was applied to probe the Al coordination environment in these U VI -contacted minerals and make inferences on the U VI coordination, in conjunction with the X-ray spectroscopy analyses. The U L III -edge XAS analysis of the U VI -contacted ettringite phases found them to be similar (>∼70%) to the uranyl oxyhydroxides present in a mixed becquerelite/metaschoepite mineral. Fitting of the EXAFS region, in combination with 27 Al NMR analysis, indicated that a disordered Ca- or Al-bearing U VI secondary phase also formed. For the U VI -contacted hydrotalcite phases, the XAS and 27 Al NMR data were interpreted as being similar to uranyl carbonate, that was likely Mg-containing., (open access.)

Published
2022
Full Text
View/download PDF

32. Contribution of energetically reactive surface features to the dissolution of CeO2 and ThO2 analogues for spent nuclear fuel microstructures.

Author

Corkhill CL, Myllykylä E, Bailey DJ, Thornber SM, Qi J, Maldonado P, Stennett MC, Hamilton A, and Hyatt NC

Abstract

In the safety case for the geological disposal of nuclear waste, the release of radioactivity from the repository is controlled by the dissolution of the spent fuel in groundwater. There remain several uncertainties associated with understanding spent fuel dissolution, including the contribution of energetically reactive surface sites to the dissolution rate. In this study, we investigate how surface features influence the dissolution rate of synthetic CeO2 and ThO2, spent nuclear fuel analogues that approximate as closely as possible the microstructure characteristics of fuel-grade UO2 but are not sensitive to changes in oxidation state of the cation. The morphology of grain boundaries (natural features) and surface facets (specimen preparation-induced features) was investigated during dissolution. The effects of surface polishing on dissolution rate were also investigated. We show that preferential dissolution occurs at grain boundaries, resulting in grain boundary decohesion and enhanced dissolution rates. A strong crystallographic control was exerted, with high misorientation angle grain boundaries retreating more rapidly than those with low misorientation angles, which may be due to the accommodation of defects in the grain boundary structure. The data from these simplified analogue systems support the hypothesis that grain boundaries play a role in the so-called "instant release fraction" of spent fuel, and should be carefully considered, in conjunction with other chemical effects, in safety performance assessements for the geological disposal of spent fuel. Surface facets formed during the sample annealing process also exhibited a strong crystallographic control and were found to dissolve rapidly on initial contact with dissolution medium. Defects and strain induced during sample polishing caused an overestimation of the dissolution rate, by up to 3 orders of magnitude.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results