CSNF Waste Form Degradation, Summary Abstraction

Steward, S.A.

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Oxygen;    Uranium Minerals;    36 Materials Science;    Waste Forms;    Dissolution;   

DOI  :  10.2172/759928
RP-ID  :  ANL-EBS-MD-000015, Rev.00
RP-ID  :  AC08-91RW00134
RP-ID  :  759928

美国|英语

来源: UNT Digital Library

【 摘 要 】

The purpose of this analysis is to provide a current summary of data and updated models for commercial spent nuclear fuel (CSNF) intrinsic (forward) dissolution (high water-flow) rates. A summary of the chemical interaction of UO{sub 2} with groundwater and its components is given in the initial analysis section. This analysis also provides a comparison of the three types of CSNF dissolution measurements available within and outside of the program. The three types of dissolution tests available are semi-static/batch, low-flow/drip, and high-flow/flow-through tests. This analysis also provides a summary of the gap and grain boundary radionuclide inventories of clad spent fuel. The final analysis topic is a comparison of the current knowledge of uranium mineral phases that form in laboratory tests with spent fuel and UO{sub 2} with the mineral assemblages found in natural uranium-bearing sites. This analysis will be incorporated into the Waste Form Degradation Process Model Report (PMR) for the Total Systems Performance Assessment-Site Recommendation. This report was developed in accordance with the technical product development plan Waste Package Materials Department Analysis and Modeling Reports Supporting the Waste Form PMR (CRWMS M and O 1999c). These models of CSNF degradation are bounding models that apply to all UO{sub 2}-based spent fuel expected to be disposed in a repository. These models are valid within the range of qualified experimental data: pH down to 3 and up to 10, oxygen pressure from 0.002 to 0.2 atmospheres, carbonate/bicarbonate concentrations from 2 x 10{sup -4} to 2 x 10{sup -2} molar. At pHs less than or equal to 7, these models are only shown to be valid at CO{sub 2} pressures of 10{sup -3} atmospheres. Corroborating data outside of these ranges indicate that the valid ranges may extend beyond those stated.