PAPER STUDY EVALUATIONS OF THE INTRODUCTION OF SMALL COLUMN ION EXCHANGE WASTE STREAMS TO THE DEFENSE WASTE PROCESSING FACILITY

Fox, K. ; Edwards, T. ; Stone, M. ; Koopman, D.

关键词: AR FACILITIES;    CONTAINERS;    CONTROL SYSTEMS;    EVALUATION;    FLEXIBILITY;    FLOWSHEETS;    GLASS;    ION EXCHANGE;    PROCESSING;    PRODUCTION;    RECOMMENDATIONS;    SLUDGES;    TANKS;    TESTING;    TITANATES;    WA;   

DOI  :  10.2172/983149
RP-ID  :  SRNL-STI-2010-00297
PID  :  OSTI ID: 983149
Others  :  TRN: US1004502

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

The objective of this paper study is to provide guidance on the impact of Monosodium Titanate (MST) and Crystalline Silicotitanate (CST) streams from the Small Column Ion Exchange (SCIX) process on the Defense Waste Processing Facility (DWPF) flowsheet and glass waste form. A series of waste processing scenarios was evaluated, including projected compositions of Sludge Batches 8 through 17 (SB8 through SB17), MST additions, CST additions to Tank 40 or to a sludge batch preparation tank (Tank 42 or Tank 51, referred to generically as Tank 51 in this report), streams from the Salt Waste Processing Facility (SWPF), and two canister production rates. A wide array of potential glass frit compositions was used to support this assessment. The sludge and frit combinations were evaluated using the predictive models in the current DWPF Product Composition Control System (PCCS). The results were evaluated based on the number of frit compositions available for a particular sludge composition scenario. A large number of candidate frit compositions (e.g., several dozen to several hundred) is typically a good indicator of a sludge composition for which there is flexibility in forming an acceptable waste glass and meeting canister production rate commitments. The MST and CST streams will significantly increase the concentrations of certain components in glass, such as Nb{sub 2}O{sub 5}, TiO{sub 2}, and ZrO{sub 2}, to levels much higher than have been previously processed at DWPF. Therefore, several important assumptions, described in detail in the report, had to be made in performing the evaluations. The results of the paper studies, which must be applied carefully given the assumptions made concerning the impact of higher Ti, Zr, and Nb concentrations on model validity, provided several observations: (1) There was difficulty in identifying a reasonable number of candidate frits (and in some cases an inability to identify any candidate frits) when a waste loading of 40% is targeted for Sludge Batches 8, 16, and 17, regardless of the addition of SCIX or SWPF streams. This indicates that the blending strategy for these sludge batches should be reevaluated by Savannah River Remediation (SRR). (2) In general, candidate frits were available to accommodate CST additions to either Tank 40 or Tank 51. A larger number of candidate frits were typically available for the sludge batches when CST is added to Tank 51 rather than Tank 40, meaning that more compositional flexibility would be available for frit selection and DWPF operation. Note however that for SB8 and SB17, no candidate frits were available to accommodate CST going to Tank 40 with and without SWPF streams. The addition of SWPF streams generally improves the number of candidate frits available for processing of a given sludge batch. (3) The change in production rate from 40 Sludge Receipt and Adjustment Tank (SRAT) batches per year (i.e., the current production rate) to 75 SRAT batches per year, without SWPF streams included, had varied results in terms of the number of candidate frits available for processing of a given sludge batch. Therefore, this variable is not of much concern in terms of incorporating the SCIX streams. Note that the evaluation at 75 SRAT batches per year (approximately equivalent to 325 canisters per year) is more conservative in terms of the impact of SCIX streams as compared to a production rate of 400 canisters per year. Overall, the outcome of this paper study shows no major issues with the ability to identify an acceptable glass processing window when CST from the SCIX process is transferred to either Tank 40 or Tank 51. The assumptions used and the model limitations identified in this report must be addressed through further experimental studies, which are currently being performed. As changes occur to the planned additions of MST and CST, or to the sludge batch preparation strategy, additional evaluations will be performed to determine the potential impacts. As stated above, the issues with Sludge Batches 8, 16, and 17 should be further evaluated by SRR. A review of Chemical Process Cell (CPC) processing identified no changes to the recommendations from the previous review of the SCIX process impacts. Recommendations for testing were made during the previous review to evaluate the impact of CST on the rheological properties of DWPF process streams and evaluate the impact of CST on catalytic hydrogen generation during CPC processing.