{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T12:52:22Z","timestamp":1792068742964,"version":"4.4.0"},"reference-count":30,"publisher":"American Chemical Society (ACS)","issue":"41","license":[{"start":{"date-parts":[[2026,9,30]],"date-time":"2026-09-30T00:00:00Z","timestamp":1790726400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"funder":[{"DOI":"10.13039\/100006147","name":"Office of Nuclear Energy","doi-asserted-by":"publisher","award":["DE-AC07-05ID1451"],"award-info":[{"award-number":["DE-AC07-05ID1451"]}],"id":[{"id":"10.13039\/100006147","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100007000","name":"Laboratory Directed Research and Development","doi-asserted-by":"publisher","award":["DE-AC07-05ID14517"],"award-info":[{"award-number":["DE-AC07-05ID14517"]}],"id":[{"id":"10.13039\/100007000","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,10,15]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>The radiolytic stability of hydroxylamine (NH3OH+) in concentrated nitric acid (HNO3) is directly relevant to plutonium finishing in used nuclear fuel reprocessing, where NH3OH+ serves as both a plutonium reductant and nitrous acid (HNO2) scavenger under high-radiation conditions. In this study, aqueous 1 M HNO3 solutions containing NH3OH+ were gamma irradiated to accumulated doses of up to 100 kGy. The radiolytic loss of NH3OH+ was found to be independent of its initial concentration, pointing to its reaction with HNO2 and hydroxyl (\u2022OH) and nitrate (NO3\u2022) radicals as the primary degradation mechanisms. Nitrous oxide (N2O) was the dominant degradation product, with smaller amounts of molecular nitrogen (N2) and hydrogen (H2)\u2500the latter exclusively from water radiolysis. A multiscale computer model was developed, combining stochastic radiation track-structure simulations with a deterministic kinetic model, and validated against the complete experimental dataset. The model quantitatively reproduced the radiolytic loss of solute NH3OH+ and solvent nitrate ions (NO3\u2013), and the evolution of N2 and H2. The N2O yields, however, are determined by reactions of the aminoxyl radical intermediate (NH2O\u2022), whose rate coefficients under strongly acidic conditions remain experimentally uncharacterized, representing the principal source of model uncertainty. Nevertheless, the presented model provides robust, quantitatively accurate predictions of NH3OH+ stability under conditions relevant to plutonium finishing operations. Because maintaining a sufficient NH3OH+ inventory is critical for holding Pu(III) prior to oxalate precipitation, the validated multiscale model is a valuable predictive tool that could be leveraged for process optimization within reprocessing flowsheets.<\/jats:p>","DOI":"10.1021\/acs.jpca.6c04665","type":"journal-article","created":{"date-parts":[[2026,10,1]],"date-time":"2026-10-01T01:01:37Z","timestamp":1790816497000},"page":"8090-8097","source":"Crossref","is-referenced-by-count":0,"title":["Gamma Radiolysis\nof Hydroxylamine in Aqueous Nitric\nAcid Solutions"],"prefix":"10.1021","volume":"130","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0745-588X","authenticated-orcid":true,"given":"Jacy K.","family":"Conrad","sequence":"first","affiliation":[{"name":"Idaho National Laboratory , , 1955 N. Fremont Ave. , , ,","place":["Idaho Falls, Idaho, United States, 83415"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseph R.","family":"Wilbanks","sequence":"additional","affiliation":[{"name":"Idaho National Laboratory , , 1955 N. Fremont Ave. , , ,","place":["Idaho Falls, Idaho, United States, 83415"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0596-0660","authenticated-orcid":true,"given":"Gregory P.","family":"Horne","sequence":"additional","affiliation":[{"name":"Idaho National Laboratory , , 1955 N. Fremont Ave. , , ,","place":["Idaho Falls, Idaho, United States, 83415"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"316","published-online":{"date-parts":[[2026,9,30]]},"reference":[{"key":"2026101508073879100_cit1","doi-asserted-by":"publisher","first-page":"104903","DOI":"10.1016\/j.pnucene.2023.104903","article-title":"A review of alternative\nfinishing options for uranium\/plutonium and minor actinide nitrate\nproducts from thermal and fast reactor fuels reprocessing","volume":"165","author":"Colledge","year":"2023","journal-title":"Prog. Nucl. Energy"},{"key":"2026101508073879100_cit2","volume-title":"Reprocessing and Recycling\nof Spent Nuclear Fuel","author":"Taylor","year":"2015"},{"issue":"1\u20132","key":"2026101508073879100_cit3","doi-asserted-by":"publisher","first-page":"3","DOI":"10.1524\/ract.1984.36.12.3","article-title":"Chemistry\nof the PUREX process","volume":"36","author":"McKibben","year":"1984","journal-title":"Radiochim. Acta"},{"key":"2026101508073879100_cit4","doi-asserted-by":"crossref","DOI":"10.2172\/4585342","article-title":"In The reaction\nof hydroxylamine with nitrous acid","volume-title":"26th Northwest\nRegional American Chemical Society Meeting","author":"Barney","year":"1971"},{"issue":"9","key":"2026101508073879100_cit5","doi-asserted-by":"publisher","first-page":"1677","DOI":"10.1016\/0022-1902(76)80660-4","article-title":"A kinetic\nstudy of the reaction of plutonium(IV) with hydroxylamine","volume":"38","author":"Barney","year":"1976","journal-title":"J. Inorg. Nucl. Chem."},{"key":"2026101508073879100_cit6","doi-asserted-by":"publisher","first-page":"756","DOI":"10.1016\/j.jnucmat.2015.06.058","article-title":"A review of plutonium\noxalate decomposition\nreactions and effects of decomposition temperature on the surface\narea of the plutonium dioxide product","volume":"465","author":"Orr","year":"2015","journal-title":"J. Nucl.\nMater."},{"key":"2026101508073879100_cit7","doi-asserted-by":"crossref","DOI":"10.2172\/4634035","volume-title":"Precipitation\nOf Plutonium(IV) Oxalate","author":"Facer","year":"1954"},{"issue":"18","key":"2026101508073879100_cit8","doi-asserted-by":"publisher","first-page":"8092","DOI":"10.1021\/acs.inorgchem.4c00138","article-title":"Multiscale\nModeling of Plutonium Radiation Chemistry in Nitric Acid Solutions.\n1. Cobalt-60 Gamma Irradiation of Pu(IV)","volume":"63","author":"Kynman","year":"2024","journal-title":"Inorg.\nChem."},{"issue":"23","key":"2026101508073879100_cit9","doi-asserted-by":"publisher","first-page":"5982","DOI":"10.1021\/ja00752a005","article-title":"Intermediates produced from the one-electron\noxidation and reduction\nof hydroxylamines. Acid-base properties of the amino, hydroxyamino,\nand methoxyamino radicals","volume":"93","author":"Simic","year":"1971","journal-title":"J. Am. Chem. Soc."},{"key":"2026101508073879100_cit10","doi-asserted-by":"publisher","first-page":"29757","DOI":"10.1039\/D2RA03392E","article-title":"Multiscale\nModelling of the Radical-Induced Chemistry of Acetohydroxamic Acid\nin Aqueous Solution","volume":"12","author":"Conrad","year":"2022","journal-title":"RSC Adv."},{"issue":"9","key":"2026101508073879100_cit11","doi-asserted-by":"publisher","first-page":"5188","DOI":"10.1039\/C9CP07034F","article-title":"Pulse radiolysis study on the reactivity\nof NO3 radical toward uranous(iv), hydrazinium nitrate\nand hydroxyl ammonium nitrate at room temperature and at 45 \u00b0C","volume":"22","author":"Musat","year":"2020","journal-title":"Phys. Chem. Chem. Phys."},{"issue":"5","key":"2026101508073879100_cit12","doi-asserted-by":"publisher","DOI":"10.1002\/cphc.202200749","article-title":"Gamma Radiation-Induced\nDegradation of Acetohydroxamic Acid (AHA) in Aqueous Nitrate and Nitric\nAcid Solutions Evaluated by Multiscale Modelling","volume":"24","author":"Conrad","year":"2023","journal-title":"ChemPhyschem"},{"key":"2026101508073879100_cit13","doi-asserted-by":"publisher","first-page":"382","DOI":"10.1016\/j.jhazmat.2013.03.031","article-title":"Thermal decomposition\nof hydroxylamine: Isoperibolic calorimetric measurements at different\nconditions","volume":"254","author":"Adamopoulou","year":"2013","journal-title":"J. Hazard. Mater."},{"issue":"5\u20136","key":"2026101508073879100_cit14","first-page":"212","article-title":"A detailed\nkinetics model for the\ndecomposition of aqueous hydroxylammonium nitrate","volume":"80","author":"Izato","year":"2019","journal-title":"Sci. Technol. Energy Mater."},{"issue":"45","key":"2026101508073879100_cit15","doi-asserted-by":"publisher","first-page":"11781","DOI":"10.1021\/acs.jpcb.6b06862","article-title":"Multi-Scale\nModeling of the Gamma Radiolysis of Nitrate Solutions","volume":"120","author":"Horne","year":"2016","journal-title":"J. Phys. Chem. B"},{"key":"2026101508073879100_cit16","doi-asserted-by":"publisher","first-page":"60","DOI":"10.1063\/1.1749558","article-title":"The Oxidation of\nFe2+ to Fe3+ by the Irradiation with\nX-Rays of Solutions of Ferrous Sulfate in Sulfuric Acid","volume":"3","author":"Fricke","year":"1935","journal-title":"J. Chem. Phys."},{"issue":"3","key":"2026101508073879100_cit17","doi-asserted-by":"publisher","first-page":"377","DOI":"10.1016\/1359-0197(91)90006-N","article-title":"Stochastic models of spur kinetics\nin water","volume":"37","author":"Pimblott","year":"1991","journal-title":"Radiat. Phys. Chem."},{"key":"2026101508073879100_cit18","doi-asserted-by":"publisher","first-page":"2673","DOI":"10.1039\/f19868202673","article-title":"Stochastic\nmodels of multispecies kinetics in radiation-induced spurs","volume":"82","author":"Clifford","year":"1986","journal-title":"J. Chem. Soc, Faraday Trans. I"},{"issue":"4","key":"2026101508073879100_cit19","first-page":"146","article-title":"The Two-Film\nTheory of Gas Absorption","volume":"26","author":"Whitman","year":"1923","journal-title":"Chem. Metall. Eng."},{"key":"2026101508073879100_cit20","unstructured":"MCPA Software.\n          \n          FACSIMILE Kinetic Modeling\nSoftware Package. MCPA Software."},{"key":"2026101508073879100_cit21","volume-title":"The Reaction Set,\nRate Constants and G-Values for the Simulation of the Radiolysis of\nLight Water Over the Range 20\u00b0 to 350\u00b0C Based on Information\nAvailable in 153-127160-450-001","author":"Elliot","year":"2009"},{"issue":"17","key":"2026101508073879100_cit22","doi-asserted-by":"publisher","first-page":"10373","DOI":"10.1021\/acs.est.5b00483","article-title":"Production of Hydroxyl Radical via\nthe Activation of Hydrogen Peroxide by Hydroxylamine","volume":"49","author":"Chen","year":"2015","journal-title":"Environ. Sci. Technol."},{"issue":"3","key":"2026101508073879100_cit23","doi-asserted-by":"publisher","first-page":"105","DOI":"10.1016\/S1010-6030(99)00191-4","article-title":"Removal of hydroxylamine\nby processes generating \u2022OH radicals in aqueous solution","volume":"129","author":"Leitner","year":"1999","journal-title":"J. Photochem. Photobiol. A-Chem."},{"issue":"2","key":"2026101508073879100_cit24","doi-asserted-by":"publisher","first-page":"180","DOI":"10.1021\/j100646a006","article-title":"Photolysis\nof hydroxylamine in aqueous\nsolution","volume":"76","author":"Behar","year":"1972","journal-title":"J. Phys. Chem."},{"issue":"1","key":"2026101508073879100_cit25","doi-asserted-by":"publisher","first-page":"192","DOI":"10.1021\/jp054747t","article-title":"Kinetic and Thermodynamic\nProperties of the Aminoxyl\n(NH2O\u2022) Radical","volume":"110","author":"Lind","year":"2006","journal-title":"J. Phys. Chem. A"},{"issue":"5","key":"2026101508073879100_cit26","doi-asserted-by":"publisher","first-page":"753","DOI":"10.1016\/1359-0197(89)90279-8","article-title":"A pulse\nradiolysis study of the temperature dependence of reactions involving\nH, OH and e-aq in aqueous solutions","volume":"34","author":"Elliot","year":"1989","journal-title":"Radiat.\nPhys. Chem."},{"issue":"15","key":"2026101508073879100_cit27","doi-asserted-by":"publisher","first-page":"8800","DOI":"10.1039\/C6RA27793D","article-title":"Reaction of\nthe hydrogen atom with\nnitrous oxide in aqueous solution - pulse radiolysis and theoretical\nstudy","volume":"7","author":"Kazmierczak","year":"2017","journal-title":"RSC Adv."},{"key":"2026101508073879100_cit28","doi-asserted-by":"publisher","first-page":"344","DOI":"10.1039\/j29680000344","article-title":"Kinetics\nand mechanism of reaction\nbetween nitrous acid and hydroxylamine 2. Alkyl hydroxylamines","volume":"3","author":"Morgan","year":"1968","journal-title":"J. Chem. Soc. B"},{"issue":"2","key":"2026101508073879100_cit29","doi-asserted-by":"publisher","first-page":"513","DOI":"10.1063\/1.555805","article-title":"Critical review\nof rate constants for reactions of hydrated electrons, hydrogen atoms\nand hydroxyl radicals (\u00b7OH\/\u00b7O-) in aqueous solution","volume":"17","author":"Buxton","year":"1988","journal-title":"J. Phys. Chem. Ref. Data"},{"issue":"11","key":"2026101508073879100_cit30","doi-asserted-by":"publisher","first-page":"7340","DOI":"10.1073\/pnas.112202099","article-title":"Nitroxyl and its\nanion in aqueous solutions: Spin states,\nprotic equilibria, and reactivities toward oxygen and nitric oxide","volume":"99","author":"Shafirovich","year":"2002","journal-title":"Proc. Natl. Acad. Sci. U. S. A."}],"container-title":["The Journal of Physical\nChemistry A"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.acs.org\/doi\/pdf\/10.1021\/acs.jpca.6c04665","content-type":"application\/pdf","content-version":"vor","intended-application":"unspecified"},{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article-pdf\/130\/41\/8090\/68720656\/acs.jpca.6c04665.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article-pdf\/130\/41\/8090\/68720656\/acs.jpca.6c04665.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T12:24:15Z","timestamp":1792067055000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.acs.org\/jpcafh\/article\/130\/41\/8090\/5443047\/Gamma-Radiolysis-of-Hydroxylamine-in-Aqueous"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,30]]},"references-count":30,"journal-issue":{"issue":"41","published-online":{"date-parts":[[2026,9,30]]},"published-print":{"date-parts":[[2026,10,15]]}},"URL":"https:\/\/doi.org\/10.1021\/acs.jpca.6c04665","relation":{},"ISSN":["1089-5639","1520-5215"],"issn-type":[{"value":"1089-5639","type":"print"},{"value":"1520-5215","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,30]]}}}