Government owned nuclear fuel from naval ship reactors, fuel element rods from Core 2 of the Shippingport, PA, pressurized water reactor, and from a variety of experimental reactors is processed to recover U-235 enriched uranium. The uranium extracted from the dissolved fuel elements is purified, converted to uranium oxide, and shipped to Oak Ridge, TN, to make fresh fuel elements. Standard practice is to optimize the production process and then select materials of construction for the equipment. The procedure had to be reversed for the Fluorinel facility because of extremely corrosive conditions sometimes encountered during the process. Selection of materials and construction of the equipment are critical because even the slightest leakage of the fluids cannot be tolerated, and repairs to highly radioactive equipment are very difficult. There are several dissolution systems, each designed to process a different type of fuel element, prior to the recovery of the uranium in the extraction process. Preliminary experiments indicated that nickel-base alloys were the only reasonable possibilities for construction of the dissolver, complexer tanks, off-gas condenser and associated piping. Alloy C-4 exhibits excellent resistance to many corrosives including mineral and organic acids, solvents, and to chlorine and its salts that cause stress corrosionmore » cracking. Alloy C-4 was selected as the best available material but the corrosion rates were still higher than might be accepted in the chemical processing industry. It was therefore necessary to determine the influence of concentration and other process variables on corrosion rate, and then to modify the dissolution and complexing process to minimize the corrosion problem.« less

The present invention provides an improved dissolution process for ZrO.sub.2 -UO.sub.2 -CaO-type pressurized water reactor fuels. The zirconium cladding is dissolved with hydrofluoric acid, immersing the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers in the resulting zirconium-dissolver-product in the dissolver vessel, and nitric acid is added to the dissolver vessel to facilitate dissolution of the uranium from the ZrO.sub.2 -UO.sub.2 -CaO fuel wafers.

During the dissolution of newer uranium-aluminum alloy fuels, uranium dissolved more slowly than aluminum.This study showed that the elutriation of uranium-aluninide particles from a continuous dissolver can be experienced.The effects of irradiation, the fuel fabrication method (wrought alloys vs powder metallurgy), and dissolver operating conditions upon this phenomenon were determined.and the shapes and sizes of such particles were compared.tions for procedures to insure complete dissolution of uranium during chemical reprocessing of uranium-aluminum fuels are made. The dissolution ratesRecommenda-

satisfactory for all solutions could not be selected. The optimum treatment for a salvage solution which was grossly contaminated with zirconium, soluble and colloidal silica, and dibutyl phosphate was to boil a 1N acid deficient solution with 600 milligrams of gelatin per liter, filter, and use a Hexone extraction system. A silicic colloid in fuel processing solutions was characterized as a surface active material by this study. (auth)

More economical methods of manufacturing aluminum-uranium fuel elements used extensively in high thermal-neutron flux reactors might be employed if the quantity of silicon allowed in the fuels could be substantially increased. Since silicon has created problems in reprocessing this type of fuel, various core and cladding alloys were examined for the effect of the silicon content upon dissolution, extraction, and solids production during dissolution. Dissolution rates in nitric acid were related to the metallurgical compositions of the alloys which, in turn, were related to their silicon content, but the effect was not sufficient to interfere with the reprocessing of the fuels. Emulsion stabilization, a problem during liquid-liquid extraction of uranium, is caused by the silicon that dissolves from the alloy as the intermetallic phase U(Al,Si)3. Silicon present in the alloy at a silicon:uranium atom ratio <1 is in the intermetallic fuel particle, while silicon in excess of approximately one atom per atom of uranium does not enter into the intermetallic phase and is present in the alloys as segregations of elemental silicon. This elemental silicon does not dissolve and remains in the dissolver solution as undesirable solids.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBarium Fluozirconate Precipitation. Improved Process for Uranium-Zirconium Alloy FuelsB. E. Paige, B. J. Newby, and K. L. RohdeCite this: Ind. Eng. Chem. Process Des. Dev. 1963, 2, 2, 112–116Publication Date (Print):April 1, 1963Publication History Published online1 May 2002Published inissue 1 April 1963https://pubs.acs.org/doi/10.1021/i260006a005https://doi.org/10.1021/i260006a005research-articleACS PublicationsRequest reuse permissionsArticle Views46Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltraviolet Spectrophotometric Determination of UraniumB. E. Paige, M. C. Elliott, and J. E. ReinCite this: Anal. Chem. 1957, 29, 7, 1029–1032Publication Date (Print):June 21, 1957Publication History Published online1 May 2002Published inissue 21 June 1957https://pubs.acs.org/doi/10.1021/ac60127a010https://doi.org/10.1021/ac60127a010research-articleACS PublicationsRequest reuse permissionsArticle Views124Altmetric-Citations15LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts