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Division Spotlight
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Latest News
Oklo completes end-to-end demonstration of advanced fuel recycling
Oklo Inc. has announced that it has completed the first end-to-end demonstration of its advanced fuel recycling process as part of an ongoing $5 million project in collaboration with Argonne and Idaho National Laboratories. Oklo’s goal: scaling up its fuel recycling capabilities to deploy a commercial-scale recycling facility that would increase advanced reactor fuel supplies and enhance fuel cost effectiveness for its planned sodium fast reactors.
Kenneth M. Wasywich, William H. Hocking, David W. Shoesmith, Peter Taylor
Nuclear Technology | Volume 104 | Number 3 | December 1993 | Pages 309-329
Technical Paper | Special Issue on Waste Management / Radioactive Waste Management | doi.org/10.13182/NT93-A34893
Articles are hosted by Taylor and Francis Online.
In the Canadian research and development program on fuel storage, used CANDU (Canada deuterium uranium) UO2fuel bundles are being exposed in experimental vessels to both dry and moisture-saturated air environments at 150°C. At intervals of several years, individual fuel elements, which were deliberately defected before storage, are recovered for destructive examination to determine the extent of UO2 oxidation that has occurred. The most recent examinations took place after 99.5 and 69 months of storage under dry and moist conditions, respectively. The progress of oxidation in the two different storage environments is compared, and the results of fuel examination by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD) are described. In dry air, oxidation proceeds mainly on exposed UO2 surfaces near the cladding defect and penetrates the fuel along grain boundaries adjoining cracks and the fuel-sheath gap, which provide primary pathways for access of oxygen to the fuel. An oxidized rind, resembling α-U3O7, is visible around UO2 grain cores near the oxide front. In moist air, oxidation is more generally distributed throughout the length of the fuel element. It proceeds along grain boundaries and is most extensive in regions of the fuel expected to have the highest porosity or grain-boundary inventory of fission products. This oxidized layer is too thin to observe by optical microscopy or identify by XRD, but XPS results indicate a higher degree of oxidation at the exposed grain boundaries (U6+/U4+ often »1.0) than in fuel specimens oxidized in dry air (U6+/U4+ usually <1.0). Interpretation of the results is complicated by the different O2/UO2 ratios in the two types of storage vessel and the fact that oxygen was completely consumed during at least some of the storage intervals. Nonetheless, it is clear that the presence of moisture promotes a more generally distributed oxidation of UO2 grain boundaries. The probable involvement of radiolytic processes in the moist oxidation reaction and possible reasons for the sensitization of certain regions of the fuel to moist oxidation are discussed. In addition to oxidation of UO2, the XPS spectra provide evidence for the radiation-induced incorporation of oxygen and nitrogen into adventitious carbon (adsorbed hydrocarbons) on the UO2 surfaces.
