Speciation and Radiation Stability of Cr and Ln “Grey-Phases” within Cr-doped (Ln,U)O 2 Spent Fuel Model Materials

Speciation and Radiation Stability of Cr and Ln “Grey-Phases” within Cr-doped (Ln,U)O 2 Spent Fuel Model Materials | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Speciation and Radiation Stability of Cr and Ln “Grey-Phases” within Cr-doped (Ln,U)O 2 Spent Fuel Model Materials Daniil Shirokiy, Andrey Bukaemskiy, Maximilian Henkes, Elena F. Bazarkina, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7704941/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 16 Feb, 2026 Read the published version in npj Materials Degradation → Version 1 posted 8 You are reading this latest preprint version Abstract Cr-doped UO₂ fuels are increasingly adopted for their superior in-reactor performance compared to undoped UO₂, but their spent fuel behaviour, particularly potential Cr speciation and fission product reactivity, remains poorly understood. This investigation has used high energy resolution fluorescence detected X-ray absorption spectroscopy to examine speciation of Cr and Pr/Gd within 200 ppm Cr-doped (U,Pr 3+ )O 2 − x and 200 ppm Cr-doped (U,Gd 3+ )O 2 − x compounds. Despite both being UO 2 soluble and undersaturated, analysis indicates that Cr 3+ and Pr 3+ /Gd 3+ form perovskite type (Pr 3+ /Gd 3+ )Cr 3+ O 3 phases, consistent with classical “grey phases” of spent fuel. The radiation tolerance of these phases was examined via swift heavy ion irradiations of PrCrO 3 and GdCrO 3 compounds where electron microscopy and grazing incidence synchrotron diffraction indicate significant amorphization but retention of the crystal structure. The investigation highlights the pertinence of considering the chemistry of dopants used for nuclear fuel enhancements regarding their speciation during irradiation and subsequent occurrence within spent fuel. Physical sciences/Chemistry Physical sciences/Materials science Physical sciences/Physics Cr-doped UO2 Grazing Incidence diffraction X-ray absorption spectroscopy Spent fuel Advanced Nuclear Fuels Full Text Additional Declarations No competing interests reported. Supplementary Files SpeciationandradstabofCrLndopedUO2SIFinal.docx Cite Share Download PDF Status: Published Journal Publication published 16 Feb, 2026 Read the published version in npj Materials Degradation → Version 1 posted Editorial decision: Revision requested 23 Dec, 2025 Reviews received at journal 18 Nov, 2025 Reviewers agreed at journal 16 Oct, 2025 Reviewers agreed at journal 15 Oct, 2025 Reviewers invited by journal 13 Oct, 2025 Editor assigned by journal 08 Oct, 2025 Submission checks completed at journal 08 Oct, 2025 First submitted to journal 24 Sep, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7704941","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":530682246,"identity":"48965ff0-925b-4d62-904f-fe48f774a714","order_by":0,"name":"Daniil Shirokiy","email":"","orcid":"","institution":"Forschungszentrum Jülich GmbH","correspondingAuthor":false,"prefix":"","firstName":"Daniil","middleName":"","lastName":"Shirokiy","suffix":""},{"id":530682247,"identity":"3f3e3c95-a8db-4a92-a18a-fe25892ff71f","order_by":1,"name":"Andrey Bukaemskiy","email":"","orcid":"","institution":"Forschungszentrum Jülich GmbH","correspondingAuthor":false,"prefix":"","firstName":"Andrey","middleName":"","lastName":"Bukaemskiy","suffix":""},{"id":530682248,"identity":"50e0072d-213c-44b9-b9c4-095a6db0f023","order_by":2,"name":"Maximilian Henkes","email":"","orcid":"","institution":"Forschungszentrum Jülich GmbH","correspondingAuthor":false,"prefix":"","firstName":"Maximilian","middleName":"","lastName":"Henkes","suffix":""},{"id":530682249,"identity":"553b16b1-1255-4d48-9549-4ae033956371","order_by":3,"name":"Elena F. 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Materials","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"npj-materials-degradation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"npjmatdeg","sideBox":"Learn more about [npj Materials Degradation](http://www.nature.com/npjmatdeg/)","snPcode":"41529","submissionUrl":"https://submission.springernature.com/new-submission/41529/3","title":"npj Materials Degradation","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Cr-doped UO2, Grazing Incidence diffraction, X-ray absorption spectroscopy, Spent fuel, Advanced Nuclear Fuels","lastPublishedDoi":"10.21203/rs.3.rs-7704941/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7704941/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eCr-doped UO₂ fuels are increasingly adopted for their superior in-reactor performance compared to undoped UO₂, but their spent fuel behaviour, particularly potential Cr speciation and fission product reactivity, remains poorly understood. This investigation has used high energy resolution fluorescence detected X-ray absorption spectroscopy to examine speciation of Cr and Pr/Gd within 200 ppm Cr-doped (U,Pr\u003csup\u003e3+\u003c/sup\u003e)O\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e and 200 ppm Cr-doped (U,Gd\u003csup\u003e3+\u003c/sup\u003e)O\u003csub\u003e2\u0026thinsp;\u0026minus;\u0026thinsp;x\u003c/sub\u003e compounds. Despite both being UO\u003csub\u003e2\u003c/sub\u003e soluble and undersaturated, analysis indicates that Cr\u003csup\u003e3+\u003c/sup\u003e and Pr\u003csup\u003e3+\u003c/sup\u003e/Gd\u003csup\u003e3+\u003c/sup\u003e form perovskite type (Pr\u003csup\u003e3+\u003c/sup\u003e/Gd\u003csup\u003e3+\u003c/sup\u003e)Cr\u003csup\u003e3+\u003c/sup\u003eO\u003csub\u003e3\u003c/sub\u003e phases, consistent with classical \u0026ldquo;grey phases\u0026rdquo; of spent fuel. The radiation tolerance of these phases was examined via swift heavy ion irradiations of PrCrO\u003csub\u003e3\u003c/sub\u003e and GdCrO\u003csub\u003e3\u003c/sub\u003e compounds where electron microscopy and grazing incidence synchrotron diffraction indicate significant amorphization but retention of the crystal structure. The investigation highlights the pertinence of considering the chemistry of dopants used for nuclear fuel enhancements regarding their speciation during irradiation and subsequent occurrence within spent fuel.\u003c/p\u003e","manuscriptTitle":"Speciation and Radiation Stability of Cr and Ln “Grey-Phases” within Cr-doped (Ln,U)O 2 Spent Fuel Model Materials","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-27 11:38:42","doi":"10.21203/rs.3.rs-7704941/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-23T14:55:53+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-11-18T10:57:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"111258975782449605939189485820984086843","date":"2025-10-16T13:35:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"333216748604907786415301705150689335873","date":"2025-10-15T15:22:35+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-13T14:55:10+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-08T15:33:43+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-08T09:33:10+00:00","index":"","fulltext":""},{"type":"submitted","content":"npj Materials Degradation","date":"2025-09-24T14:51:51+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-materials-degradation","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"npjmatdeg","sideBox":"Learn more about [npj Materials Degradation](http://www.nature.com/npjmatdeg/)","snPcode":"41529","submissionUrl":"https://submission.springernature.com/new-submission/41529/3","title":"npj Materials Degradation","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"NPJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"1bebf92f-9f4e-4b49-ac61-4e8d9d8fbced","owner":[],"postedDate":"October 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":56416361,"name":"Physical sciences/Chemistry"},{"id":56416362,"name":"Physical sciences/Materials science"},{"id":56416363,"name":"Physical sciences/Physics"}],"tags":[],"updatedAt":"2026-02-23T16:02:34+00:00","versionOfRecord":{"articleIdentity":"rs-7704941","link":"https://doi.org/10.1038/s41529-026-00752-5","journal":{"identity":"npj-materials-degradation","isVorOnly":false,"title":"npj Materials Degradation"},"publishedOn":"2026-02-16 15:58:57","publishedOnDateReadable":"February 16th, 2026"},"versionCreatedAt":"2025-10-27 11:38:42","video":"","vorDoi":"10.1038/s41529-026-00752-5","vorDoiUrl":"https://doi.org/10.1038/s41529-026-00752-5","workflowStages":[]},"version":"v1","identity":"rs-7704941","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7704941","identity":"rs-7704941","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}