Incorporation of radionuclides in the alteration phases of spent nuclear fuel.
Alteration may be expected for spent nuclear fuel exposed to groundwater under oxidizing conditions such as that which exist at the proposed nuclear waste repository at Yucca Mountain, Nevada. The actinide elements released during the corrosion of spent fuel may be incorporated into the structures of secondary U{sup 6+} phases. The incorporation of transuranics into the crystal structures of the alteration products may significantly decrease their mobility. A series of precipitation tests were conducted at 90 C to determine the potential incorporation of Ce{sup 4+} and Nd{sup 3+} (surrogates for Pu{sup 4+} and Am{sup 3+}, respectively) into uranyl phase. Dehydrated schoepite (UO{sub 3}{center_dot}0.8-1.0HP{sub 2}O) was produced by hydrolysis of a uranium oxyacetate solution containing either cerium or neodymium. ICP-MS analysis of the leachant, leachate, and solid phase reaction products which were dissolved in a HNO{sub 3} solution indicates that 26 ppm of Ce was incorporated into dehydrated schoepite. ICP-MS results from the Nd-doped tests indicate significant neodymium incorporation as well, however, the heterogeneous distribution of Nd in the solid phase noted during the AEM/EELS examination implies that neodymium may not incorporate into the structure of dehydrated schoepite.
- Research Organization:
- Argonne National Lab., IL (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 11950
- Report Number(s):
- ANL/CMT/CP-99894; TRN: US0102300
- Resource Relation:
- Conference: Migration '99, Lake Tahoe, NV (US), 09/26/1999--10/01/1999; Other Information: PBD: 25 Aug 1999
- Country of Publication:
- United States
- Language:
- English
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