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Ultra-high-performance grout (UHPG) grout appears to be good candidate for solidification and encapsulation of waste containing 99 Tc and 129 I that benefits from low Dobs. The properties that make UHPG a good candidate for encapsulating HEPA filters would make it a good option for microencapsulating other solid secondary waste (SSW) such as granular activated carbon, silver mordenite, and ion exchange resins. Containers made of UHPG would also be good candidates for dry disposal of SSW due to its very low diffusivity which prevents contaminant migration. Contaminated high-efficiency particulate air (HEPA) filters will be generated during operation of the secondary off-gas treatment system in the Low Activity Waste (LAW) Facility of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The HEPA filters receive off-gas from the vessel vent header and primary off-gas treatment system in LAW Facility and remove particulate contaminants including 99 Tc and 129 I salts. The current disposal method for HEPA filters is encapsulation in metal containers using grout and placement in the Integrated Disposal facility (IDF), (Nichols et al., 2017). Results from calculations supporting the IDF Performance Assessment (PA) demonstrated that contaminated HEPA filters from the WTP are the largest contributors to groundwater impacts and dose to a member of the public in the future from contaminants of potential concern (CoPC), including 129 I and 99 Tc. 129 I Kd, mL/g 110 110 Rf 517 1600 Dobs, m 2 /s 3.2 x 10-13 1.7 x 10-19 Deff, m 2 /s 1.7 x 10-10 2.7 x 10-16 Note: a insufficient spike in Baseline grout to measure Kd, b not solubility controlled in Baseline grout, c solubility controlled in UHPG.
Ultra-high-performance grout (UHPG) grout appears to be good candidate for solidification and encapsulation of waste containing 99 Tc and 129 I that benefits from low Dobs. The properties that make UHPG a good candidate for encapsulating HEPA filters would make it a good option for microencapsulating other solid secondary waste (SSW) such as granular activated carbon, silver mordenite, and ion exchange resins. Containers made of UHPG would also be good candidates for dry disposal of SSW due to its very low diffusivity which prevents contaminant migration. Contaminated high-efficiency particulate air (HEPA) filters will be generated during operation of the secondary off-gas treatment system in the Low Activity Waste (LAW) Facility of the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The HEPA filters receive off-gas from the vessel vent header and primary off-gas treatment system in LAW Facility and remove particulate contaminants including 99 Tc and 129 I salts. The current disposal method for HEPA filters is encapsulation in metal containers using grout and placement in the Integrated Disposal facility (IDF), (Nichols et al., 2017). Results from calculations supporting the IDF Performance Assessment (PA) demonstrated that contaminated HEPA filters from the WTP are the largest contributors to groundwater impacts and dose to a member of the public in the future from contaminants of potential concern (CoPC), including 129 I and 99 Tc. 129 I Kd, mL/g 110 110 Rf 517 1600 Dobs, m 2 /s 3.2 x 10-13 1.7 x 10-19 Deff, m 2 /s 1.7 x 10-10 2.7 x 10-16 Note: a insufficient spike in Baseline grout to measure Kd, b not solubility controlled in Baseline grout, c solubility controlled in UHPG.
Washington River Protection Solutions (WRPS) commissioned the Savannah River National Laboratory (SRNL) (Brown, 2016) to develop and implement a testing program to support the findings presented in the SSW data package for the Integrated Disposal Facility Performance Assessment (IDF PA) (Flach et al., 2016a). The specific objectives of the work in this report are to; measure fresh and cured properties of a grouted waste form consisting of cementitious material and spherical rescorcinol formaldehyde cation exchange resin measure the partition coefficient of technetium and iodine in grout matrices This a report presents results from the work on this project completed by SRNL in FY17.Operation of the low activity waste vitrification facility (LAW) part of the Waste Treatment and Immobilization Plant (WTP) at Hanford will generate several solid secondary waste (SSW) streams including used process equipment, contaminated tools and instruments, decontamination wastes, highefficiency particulate air filters (HEPA), carbon absorption beds, silver mordenite iodine sorbent beds, and spent ion exchange resins (IXr), all of which are to be disposed of in the Integrated Disposal Facility (IDF). The baseline treatment method in the IDF Performance Assessment (PA) for SSW is solidification/stabilization using cementitious material. The Hanford Mix 5 has been identified as the baseline grout for encapsulation of debris SSW (HEPA filters) and solidification/stabilization of non-debris SSW (carbon absorption beds, silver mordenite iodine sorbent beds, and spent ion exchange resins). Hanford Mix 5 is a blend of ASTM (C150-18) Type I-II cement (OPC), Class F fly ash (FA), water, BASF Pozzolith 80 and BASF Master Fiber M100 (fiber) that is currently used for disposal of debris in carbon steel containers (B25) in Hanford's 200 West Area Low Level Waste Burial Ground trenches. This report documents the results of studies performed by the SRNL to evaluate (1) the stabilization of spherical rescorcinol formaldehyde (sRF) resin, a cation exchange resin in grout consisting of OPC, FA, and blast furnace slag (BFS) and (2) retention of 99Tc and iodine in grout. Three different mixes of cementitious material (CM) were tested including the Hanford Grout Mix 5. The CM mixes tested contained 75:25:0 (
An expert panel consisting of the document authors was assembled by Washington River Protection Solutions, LLC (WRPS) and tasked with (1) identifying technical and regulatory limitations to treating and disposing of grouted low-activity waste (LAW), and (2) with identifying and evaluating a wide range of technical solutions to these limitations. The analysis included technologies to allow inventory management and/or improve retention of iodine, technetium, and nitrate either in the waste packages, or within the Integrated Disposal Facility (IDF), and, technologies to ensure regulated organics are below Resource Conservation and Recovery Act of 1976 (RCRA) Land Disposal Restriction (LDR) levels.The expert panel completed their analysis in three distinct phases. In Phase I, the team reviewed the chemical and physical characteristics of the most recent projected supplemental LAW (SLAW) feed vector along with disposal site waste acceptance criteria and the fiscal year 2019 results from Pacific Northwest National Laboratory that identified the level of improvement that would be needed to meet onsite disposal requirements in the IDF (Asmussen et al. 2019a). The two regulatory constraints targeted for technology solutions by the expert panel were (1) current estimates based on performance assessment fate-andtransport modeling indicate that if the entire quantity of LAW currently designated for supplemental treatment were solidified as a cementitious material, nitrate, 99-Tc, and 129-I could exceed groundwater standards after DOE's time of compliance (1,000 years) but within 10,000 years after IDF closure and (2) LAW may contain RCRA LDR organics at levels that require removal to meet LDR concentration-based limits. It should also be noted that the first issue is only applicable to on-site disposal, not offsite at WCS and is based on calculations that assume either a low-performing grout is used, or high-performance grout does not maintain its performance (SRNL-RP-2018-00687). Asmussen et al. (2019a) estimated that the inventory of grouted SLAW could meet IDF groundwater requirements if the release rate of nitrate, 99-Tc, and 129-I were reduced by a factor of approximately 3.2, 10, and 32, respectively versus baseline formulation performance.In Phase II, an extensive list of technologies and engineering approaches was identified and subjected to an initial assessment by the group. Current knowledge associated with technology maturation needs and constraints to implementation at Hanford were recorded in 13 distinct categories. In the final phase of the process (Phase III), the expert panel selected 7 of the 13 categories for qualitative rating and a series of meetings were held between the expert panel to discuss and rate each technology in each category. All ratings were developed by consensus. After the qualitative rating was complete, a numerical scoring criterion for each category was applied and a composite score for the individual technologies was calculated. An uncertainty score was also developed for each technolo...
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