Pu Glass Fabrication and Product Consistency Testing
The DOE/EM plans to conduct the Plutonium Vitrification Project at the Savannah River Site (SRS). An important part of this project is to reduce the attractiveness of the plutonium by fabricating a plutonium glass form and immobilizing the Pu form within the high level waste (HLW) glass prepared in the Defense Waste Processing Facility (DWPF). This requires that a project schedule that is consistent with EM plans for DWPF and cleanup of the SRS be developed. Critical inputs to key decisions in the vitrification project schedule are near-term data that will increase confidence that lanthanide borosilicate (LaBS) glass product is suitable for disposal in the Yucca Mountain Repository. A workshop was held on April 28, 2005 at Bechtel SAIC Company facility in Las Vegas, NV to define the near term data needs. Dissolution rate data and the fate of plutonium oxide and the neutron absorbers during the dissolution process were defined as key data needs. A suite of short-term tests were defined at the workshop to obtain the needed data. The objectives of these short-term tests are to obtain data that can be used to show that the dissolution rate of a LaBS glass is acceptable and to show that the extent of Pu separation from neutron absorbers, as the glass degrades and dissolves, is not likely to lead to criticality concerns. An additional data need was identified regarding the degree of macroscopic cracking that occurs during processing of the Pu glass waste form and subsequent pouring of HLW glass in the DWPF. A final need to evaluate new frit formulations that may increase the durability of the plutonium glass and/or decrease the degree to which neutron absorbers separate from the plutonium during dissolution was identified. This task plan covers testing to support a near term data need regarding glass dissolution performance. Separate task plans will be developed for testing to address the degree of macroscopic cracking and the development of alternative frit formulations. The Product Consistency Test (PCT) was identified as a means to provide some of the near term performance data. The PCT is a static test method in which known masses of crushed glass and demineralized water are reacted for a desired duration [1]. There are two reasons to perform the PCT. The first is that the results are used as a measure of acceptance in the Waste Acceptance Product Specifications Document (WAPS) [2]. The second is the need for long-term static test results that can be used to verify the applicability of the degradation model. Thus, the primary focus will be on the use of the PCT Method B (PCT-B) to study the formation and stability of colloids and to study alteration phases formed on the glass surface. The standard 7-day PCT in demineralized water (PCT-A) will be included to demonstrate compliance with the waste acceptance criterion and determine the value of the k{sub E} rate parameter for comparison with the Defense HLW Glass Degradation Model [3].
- Research Organization:
- Savannah River Site (SRS), Aiken, SC
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC09-96SR18500
- OSTI ID:
- 881502
- Report Number(s):
- WSRC-RP-2005-01676; TRN: US0603151
- Country of Publication:
- United States
- Language:
- English
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GLASS FABRICATION AND PRODUCT CONSISTENCY TESTING OF LANTHANIDE BOROSILICATE FRIT B COMPOSITION FOR PLUTONIUM DISPOSITION
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