Dual Purpose Canister Reactivity and Groundwater Absorption Analyses

Abstract

Appendix A is added. Appendix A contains (1) post-closure criticality results with principal set of 29 isotopes (recommended for post-closure criticality analysis) for eight sites (total 215 DPCs), (2) reactivity reduction study results by groundwater species applied to as-loaded DPCs, and (3) reactivity impact of filler material applied to as-loaded DPCs. In the main body, Figures 2, 5-9, and 11 are updated to be consistent with FCRD-UFD-2014-000069, Investigation of . Changes in the main body are identified by a black vertical line in the margin. FCRD-UFD-2014-000520, Revision 2Appendix B is added. Appendix B contains (1) post-closure criticality results for 16 new sites (total 339 DPCs), and(2) reactivity reduction study by groundwater species (NaCl) applied to as-loaded DPCs at 16 sites. Changes in the main body are identified by a black vertical line in the margin. FCRD-UFD-2014-000520, Revision 3Appendix C is added. Appendix C contains a misload methodology for as-loaded disposal calculations and an evaluation for misload of 3 sites and 99 canisters. Changes in the main body are identified by a black vertical line in the margin. FCRD-UFD-2014-000520, Revision 4Appendix D is added. Appendix D contains (1) a description of the criticality models for the NUHOMS ® 24PT1-DSC and NUHOMS ® 32 PT-DSC DPCs, (2) post-closure criticality calculation results for five sites (total 60 DPCs), (3) reactivity reduction study results by groundwater species applied to as-loaded DPCs, (4) misload analyses assuming the worst fuel assembly configuration in an asloaded canister, and (5) a filler height scoping calculation. FCRD-UFD-2014-000520, Revision 5Appendix E is added. Appendix E contains: (1) a description of the criticality models for the NUHOMS ® 32 PT-DSC and NUHOMS ® 61 BT-DSC loss of absorber models, (2) post-closure criticality calculation results for five sites (total 92 DPCs), (3) reactivity reduction study results by groundwater species applied to asloaded DPCs, and (4) misload analyses assuming the worst fuel assembly configuration in an as-loaded canister. FCRD-UFD-2014-000520, Revision 6Appendix F is added. Appendix F contains calculations that (1) extend the analytical timeline for the 708 canisters analyzed through FY19 from 22,000 years to 1,100,000 years, (2) characterize the effects of cementitious filler materials have on post closure criticality scenarios, (3) provide post-closure criticality calculation results for four sites (66 new DPCs), (4) provide reactivity reduction study results by groundwater species applied to as-loaded DPCs, and (5) present misload analyses

Insert Modeling in UNF ST&DARDS

“…These depletion calculations include each cycle the assembly experienced, and the associated decay time between cycles. After the last cycle, each assembly was decayed out to the analysis date of this work, which was the year 22,000 [8].…”

Basket Modification Concepts for Disposal Reactivity Control of Dual Purpose Canisters

“…The burnup credit and criticality computational methods used to perform this work are discussed at length in Clarity et al [4]. The same computational pipeline, ORIGEN reactor libraries, and DPC computational templates are used here as in the previous work [4].…”

“…The burnup credit and criticality computational methods used to perform this work are discussed at length in Clarity et al [4]. The same computational pipeline, ORIGEN reactor libraries, and DPC computational templates are used here as in the previous work [4]. All criticality calculations performed to support this work used the SCALE 6.2.3 version of the KENO-VI Monte Carlo code with ENDF/B-VII.1 nuclear data.…”

“…Based on previous screening criteria, options available for excluding a feature, event, or process consisted of a low-probability criterion, a low-consequence criterion, and regulation. Previous work by Clarity et al [4] showed that, in many cases, considering the as-loaded contents of DPCs is enough to offset the [4] by incorporating various basket modification strategies in order to suppress reactivity. The basket modification analysis was performed by modifying the models of selected canisters that were analyzed in the prior work [4] to include proposed neutron absorbing technologies than can be credited in repository environments.…”