Waste Package Related Impacts of Plutonium Disposition Waste Form Geologic Repository

This report provides a comprehensive summary of the waste package (WP) related impacts of the Plutonium Disposition waste forms that are being developed and evaluated by the Office of Fissile Materials Disposition of the DOE. These waste forms are of two distinct types. One type is mixed oxide spent nuclear fuel (MOX SNF), which would be received from one or more commercial nuclear reactors using MOX fuel prepared from surplus weapons plutonium. The other type is plutonium immobilized in ceramic disks, which would be embedded in HLW glass in the standard HLW glass disposal canister. The ceramic disks would occupy approximately 12% of the HLW canister volume, while most of the remaining 88% of the volume would be occupied by HLW glass. The studies reported here have been ongoing for five years, and much of the work has been presented in one of four previous annual reports. This is the first of the reports to be subject to requirements of the Office of Civilian Radioactive Waste Management Quality Assurance Requirements (DOE 1998a and CRWMS M&O 1999p). This compliance is necessary in order that the results presented here be applicable to the major upcoming OCRWM project statutory and licensing documents: the Site Recommendation, and the License Application. It is, therefore, necessary to confirm some of the results from the prior year's reports. A summary distinguishing the results that are new this year is given at the end of this executive summary. The two basic WP designs used for this study are identical to those that have been used for the commercial SNF and the HLW glass; they are used here for the MOX SNF and the immobilized plutonium, respectively. These WP designs were used for the OCRWM Viability Assessment of a Repository at Yucca Mountain (VA) document, which was recently delivered to the US Congress. The improved performance expected with these new WP designs will be covered in the Waste Package Related Impacts report for next year