{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,23]],"date-time":"2026-07-23T09:21:11Z","timestamp":1784798471479,"version":"3.55.0"},"reference-count":44,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"U.S. Department of Energy NEUP program","award":["DE-NE0009134"],"award-info":[{"award-number":["DE-NE0009134"]}]},{"name":"U.S. Department of Energy NEUP program","award":["DE-AC07-05ID14517"],"award-info":[{"award-number":["DE-AC07-05ID14517"]}]},{"name":"Nuclear Energy of the U.S. Department of Energy and the Nuclear Science User Facilities","award":["DE-NE0009134"],"award-info":[{"award-number":["DE-NE0009134"]}]},{"name":"Nuclear Energy of the U.S. Department of Energy and the Nuclear Science User Facilities","award":["DE-AC07-05ID14517"],"award-info":[{"award-number":["DE-AC07-05ID14517"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>This study presents a novel multiphysics phase-field fracture model to analyze high-burnup uranium dioxide (UO2) fuel behavior under transient reactor conditions. Fracture is treated as a stochastic phase transition, which inherently accounts for the random microstructural effects that lead to variations in the value of fracture strength. Moreover, the model takes into consideration the effects of temperature and burnup on thermal conductivity. Therefore, the model is able to predict crack initiation, propagation, and complex morphologies in response to thermal gradients and stress distributions. Several simulations were conducted to investigate the effects of operational and transient conditions on fracture behavior and the resulting cracking patterns. High-burnup fuels exhibit reduced thermal conductivity, elevating temperature gradients and resulting in extensive radial and circumferential cracks. Transient heating rates and temperatures significantly affect fracture patterns, with higher heating rates generating steeper gradients and more irregular crack trajectories. This approach provides critical insights into fuel integrity during accident scenarios and supports the safety evaluation of extended burnup limits.<\/jats:p>","DOI":"10.3390\/ma18051162","type":"journal-article","created":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T09:37:52Z","timestamp":1741167472000},"page":"1162","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Thermo-Mechanical Phase-Field Modeling of Fracture in High-Burnup UO2 Fuels Under Transient Conditions"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6903-4872","authenticated-orcid":false,"given":"Merve","family":"Gencturk","sequence":"first","affiliation":[{"name":"Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicholas","family":"Faulkner","sequence":"additional","affiliation":[{"name":"Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karim","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843, USA"},{"name":"Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,3,5]]},"reference":[{"key":"ref_1","unstructured":"Geelhood, K. (2019). Fuel Performance Considerations and Data Needs for Burnup Above 62 GWd\/MTU, PNNL-29368, Pacific Northwest National Laboratory."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1016\/0022-3115(86)90028-0","article-title":"Fission gas release from power-ramped UO2 fuel","volume":"139","author":"Hastings","year":"1986","journal-title":"J. Nucl. Mater."},{"key":"ref_3","unstructured":"Bleiberg, M., Berman, R., and Lustman, B. (1963). Effects of High Burn-Up on Oxide Ceramic Fuels, IAEA International Atomic Energy Agency (IAEA). Effets de Taux de Combustion Eleves sur les Oxydes CeramiquesCombustibles; Efectos de un Elevado Grado de Combusti\u00f3n Sobre los Combustibles a Base de \u00f3xidos Cer\u00e1micos."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/0022-3115(95)00116-6","article-title":"Modelling the high burnup UO2 structure in LWR fuel","volume":"226","author":"Lassmann","year":"1995","journal-title":"J. Nucl. Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"65","DOI":"10.1016\/0022-3115(92)90455-T","article-title":"Microstructural change and its influence on fission gas release in high burnup UO2 fuel","volume":"188","author":"Une","year":"1992","journal-title":"J. Nucl. Mater."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/0168-583X(94)96235-9","article-title":"Radiation-induced microstructural change in high burnup UO2 fuel pellets","volume":"Volume 91","author":"Nogita","year":"1994","journal-title":"Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"170","DOI":"10.1016\/S0022-3115(97)00171-2","article-title":"Formation of the rim structure in high burnup fuel","volume":"248","author":"Matzke","year":"1997","journal-title":"J. Nucl. Mater."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/S0022-3115(97)00015-9","article-title":"An electron microscopy study of the RIM structure of a UO2 fuel with a high burnup of 7.9% FIMA","volume":"245","author":"Ray","year":"1997","journal-title":"J. Nucl. Mater."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/0022-3115(92)90457-V","article-title":"Microstructural analysis of LWR spent fuels at high burnup","volume":"188","author":"Thomas","year":"1992","journal-title":"J. Nucl. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Barner, J.O., Cunningham, M.E., Freshley, M.D., and Lanning, D.D. (1990). High Burnup Effects Program, U.S. Department of Energy. Technical Report.","DOI":"10.2172\/5876135"},{"key":"ref_11","unstructured":"Raynaud, P. (2012). NUREG-2121: Fuel Fragmentation, Relocation, and Dispersal During the Loss-of-Coolant Accident, US Nuclear Regulatory Commission."},{"key":"ref_12","unstructured":"NEA (2016). Report on Fuel Fragmentation, Relocation and Dispersal (FFRD), OECD Publishing."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"152750","DOI":"10.1016\/j.jnucmat.2020.152750","article-title":"A Critical Review of High Burnup Fuel Fragmentation, Relocation, and Dispersal under Loss-of-Coolant Accident Conditions","volume":"546","author":"Capps","year":"2021","journal-title":"J. Nucl. Mater."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/0022-3115(94)90276-3","article-title":"Temperature measurements in high burnup UO2 nuclear fuel: Implications for thermal conductivity, grain growth and gas release","volume":"211","author":"Bagger","year":"1994","journal-title":"J. Nucl. Mater."},{"key":"ref_15","unstructured":"Nakamura, J., Uchida, M., Uetsuka, H., and Furuta, T. (1998). Thermal Diffusivity of High Burnup UO2 Pellet, International Atomic Energy Agency (IAEA). IAEA-TECDOC\u20131036."},{"key":"ref_16","unstructured":"International Atomic Energy Agency (1998). Advances in Fuel Pellet Technology for Improved Performance at High Burnup Proceedings of a Technical Committee Meeting, International Atomic Energy Agency (IAEA). IAEA-TECDOC\u20131036."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"477","DOI":"10.13182\/NSE14-20","article-title":"An Assessment of the Fuel Pulverization Threshold During LOCA-Type Temperature Transients","volume":"179","author":"Turnbull","year":"2015","journal-title":"Nucl. Sci. Eng."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.net.2017.12.002","article-title":"Focused ion beam\u2013scanning electron microscope examination of high burn-up UO2 in the center of a pellet","volume":"50","author":"Noirot","year":"2018","journal-title":"Nucl. Eng. Technol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1016\/j.jnucmat.2018.05.077","article-title":"Restructuring in high burnup UO2 studied using modern electron microscopy","volume":"509","author":"Gerczak","year":"2018","journal-title":"J. Nucl. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"154605","DOI":"10.1016\/j.jnucmat.2023.154605","article-title":"Characterization of the radial microstructural evolution in LWR UO2 using electron backscatter diffraction","volume":"585","author":"McKinney","year":"2023","journal-title":"J. Nucl. Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"153719","DOI":"10.1016\/j.jnucmat.2022.153719","article-title":"Experimentally validated multiphysics modeling of fracture induced by thermal shocks in sintered UO2 pellets","volume":"565","author":"McClenny","year":"2022","journal-title":"J. Nucl. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"793","DOI":"10.1016\/j.ceramint.2020.08.191","article-title":"Multiphysics phase-field modeling of quasi-static cracking in urania ceramic nuclear fuel","volume":"47","author":"Li","year":"2021","journal-title":"Ceram. Int."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1085","DOI":"10.1016\/0001-6160(79)90196-2","article-title":"A microscopic theory for antiphase boundary motion and its application to antiphase domain coarsening","volume":"27","author":"Allen","year":"1979","journal-title":"Acta Metall."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.ijplas.2018.07.005","article-title":"Thermodynamically consistent and scale-dependent phase field approach for crack propagation allowing for surface stresses","volume":"111","author":"Levitas","year":"2018","journal-title":"Int. J. Plast."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"134206","DOI":"10.1103\/PhysRevB.66.134206","article-title":"Three-dimensional Landau theory for multivariant stress-induced martensitic phase transformations. I. Austenite \u2194 martensite","volume":"66","author":"Levitas","year":"2002","journal-title":"Phys. Rev. B"},{"key":"ref_26","first-page":"163","article-title":"VI. The phenomena of rupture and flow in solids. Philosophical Transactions of the Royal Society of London. Series A, Containing Papers of a Mathematical or Physical Character","volume":"221","author":"Griffith","year":"1921","journal-title":"Royal Soc."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"152209","DOI":"10.1016\/j.jnucmat.2020.152209","article-title":"Fracture properties of an irradiated PWR UO2 fuel evaluated by micro-cantilever bending tests","volume":"538","author":"Henry","year":"2020","journal-title":"J. Nucl. Mater."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/bs.aams.2019.08.001","article-title":"Phase-field modeling of fracture","volume":"Volume 53","author":"Wu","year":"2020","journal-title":"Advances in Applied Mechanics"},{"key":"ref_29","unstructured":"OECD, and Nuclear Energy Agency (1999). Thermal Performance of High Burn-Up LWR Fuel: Seminar Proceedings, Cadarache, France, 3\u20136 March 1998, OECD."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.jnucmat.2014.07.006","article-title":"Effect of burn-up on the thermal conductivity of uranium\u2013gadolinium dioxide up to 100 GWd\/tHM","volume":"453","author":"Staicu","year":"2014","journal-title":"J. Nucl. Mater."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1768","DOI":"10.1016\/j.nucengdes.2009.05.021","article-title":"MOOSE: A parallel computational framework for coupled systems of nonlinear equations","volume":"239","author":"Gaston","year":"2009","journal-title":"Nucl. Eng. Des."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/0022-3115(65)90089-9","article-title":"Elastic constants of single crystal UO2 at 25 \u00b0C","volume":"16","author":"Wachtman","year":"1965","journal-title":"J. Nucl. Mater."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"012025","DOI":"10.1088\/1757-899X\/130\/1\/012025","article-title":"Thermal properties of nonstoichiometry uranium dioxide","volume":"130","author":"Kavazauri","year":"2016","journal-title":"IOP Conf. Ser. Mater. Sci. Eng."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/0022-3115(81)90541-9","article-title":"Thermophysical properties of uranium dioxide","volume":"102","author":"Fink","year":"1981","journal-title":"J. Nucl. Mater."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1005","DOI":"10.1080\/18811248.1982.9734249","article-title":"Microstructure Effects on Fracture Strength of U02 Fuel Pellets","volume":"19","author":"Oguma","year":"1982","journal-title":"J. Nucl. Sci. Technol."},{"key":"ref_36","unstructured":"Williamson, R., and Knoll, D. (2009). Simulating Dynamic Fracture in Oxide Fuel Pellets Using Cohesive Zone Models, IASMiRT."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1016\/0029-5493(83)90045-6","article-title":"Cracking and relocation behavior of nuclear fuel pellets during rise to power","volume":"76","author":"Oguma","year":"1983","journal-title":"Nucl. Eng. Des."},{"key":"ref_38","unstructured":"Motta, A., Olander, D., and Wirth, B. (2017). Light Water Reactor Materials, American Nuclear Society. American Nuclear Society Scientific Publications."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"153163","DOI":"10.1016\/j.jnucmat.2021.153163","article-title":"Mechanistic verification of empirical UO2 fuel fracture models","volume":"556","author":"Gamble","year":"2021","journal-title":"J. Nucl. Mater."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1016\/j.actamat.2020.06.038","article-title":"Extended defect change in UO2 during in situ TEM annealing","volume":"196","author":"Onofri","year":"2020","journal-title":"Acta Mater."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1016\/0022-3115(79)90165-X","article-title":"Effect of fabrication parameters and microstructure on the mechanical strength of UO2 fuel pellets","volume":"84","author":"Radford","year":"1979","journal-title":"J. Nucl. Mater."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"102665","DOI":"10.1016\/j.tafmec.2020.102665","article-title":"UO2 micron scale specimen fracture: Parameter identification and influence of porosities","volume":"108","author":"Doitrand","year":"2020","journal-title":"Theor. Appl. Fract. Mech."},{"key":"ref_43","unstructured":"Karb, E.H., Pr\u00fc\u00dfmann, M., Sepold, L., Hofmann, P., and Schanz, G. (1983). LWR Fuel Rod Behaviorin the FR2 Ln-Pile Tests Simulating the Heatup Phase of a LOCA, IAEA."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/0022-3115(85)90062-5","article-title":"Integrity degradation of UO2 pellets subjected to thermal shock","volume":"127","author":"Oguma","year":"1985","journal-title":"J. Nucl. Mater."}],"container-title":["Materials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1996-1944\/18\/5\/1162\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T16:47:43Z","timestamp":1760028463000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1996-1944\/18\/5\/1162"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,5]]},"references-count":44,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2025,3]]}},"alternative-id":["ma18051162"],"URL":"https:\/\/doi.org\/10.3390\/ma18051162","relation":{},"ISSN":["1996-1944"],"issn-type":[{"value":"1996-1944","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,5]]}}}