Progress Report on the Laboratory Testing of the Bulk Vitrification Cast Refractory

Pierce, Eric M.; McGrail, B. Peter; Bagaasen, Larry M.; Wellman, Dawn M.; Crum, Jarrod V.; Geiszler, Keith N.; Baum, Steven R.

doi:10.2172/15020765

“…The profile from these data shows no tendency for the soluble amount of Re to decrease with distance from the interface up to 10 mm. Earlier tests (Pierce et al 2004) showed that the soluble Re concentration decreased significantly at distances >18 mm from the interface. Future layer-by-layer grinding tests should be conducted to greater depths with increased sample sizes to provide large enough samples for chemical analysis.…”

Section: Comparison To 1/6 Th Scale Melter Datamentioning

confidence: 93%

“…As described in Pierce et al (2004), the refractory sample was weighed, placed into a known volume of 0.001 M HNO 3 leaching solution, and vacuum saturated at a pressure of 84.6 kPa (12.3 lb in -2 ) for no less than 4 hours. An aliquot of the saturation solution was removed and analyzed for Re with ICP-MS.…”

Section: Suspended Refractory Rod Testmentioning

confidence: 99%

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Bulk Vitrification Castable Refractory Block Protection Study

Hrma¹,

Bagaasen²,

Beck³

et al. 2005

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Executive SummaryThe U.S. Department of Energy is constructing a waste treatment plant at the Hanford Site in southeastern Washington State to vitrify the large amount of radioactive waste stored in underground tanks. Supplemental treatment technologies were studied to accelerate the cleanup of low-activity waste, and a decision was made to proceed with a pilot-scale test and demonstration facility to further evaluate bulk vitrification (BV).Experimental research, engineering-scale (ES) tests, and the science of glass melting provide ample evidence that a small fraction of Tc and Re were transferred out of the low-activity waste (LAW) glass feed and molten LAW glass and deposited on the surface and within the internal pore surfaces of the castable refractory block (CRB), both by low-temperature molten salt penetration and by hightemperature evaporation-condensation. In this task, laboratory experiments were undertaken to evaluate the capability of these two mechanisms to transport Tc/Re into the CRB during vitrification and to evaluate various means of CRB protection against the deposition of leachable radioactive Tc (and Re, its nonradioactive surrogate). All tests conducted in this task and described in this report used Re as a chemical surrogate for Tc.Both standard and newly designed experimental methods were applied to assess the extent of Tc/Re transport to the CRB, both unprotected (the baseline) and protected with a glaze or a tile. These methods include:• the measurement of Re concentration distribution in an unprotected CRB sample taken from an ES test • suspended refractory rod test for vapor deposition• simulant condensate penetration tests to determine the penetration of vapor condensates• gas permeability test and porosity measurement for vapor penetration• partially immersed rod test for molten salt penetration• manufacturing demonstration testing to determine the compatibility of tiles and CRB and the adherence of tile to CRB • refractory corrosion test for tiles.In many cases, experimental conditions were selected to enhance the transport mechanism so as to make the very small levels of Tc/Re normally transported easier to detect.The tests with unprotected (baseline) CRB showed that the molten LAW penetrates into CRB pores before it converts to glass, leaving deposits of sulfates and chlorides when the nitrate components decompose. Na 2 O from the LAW reacts with the CRB to create a durable glass phase that may contain limited quantities of insoluble Tc/Re. Limited data from a single CRB sample taken from an ES experiment indicates that, while a fraction of Tc/Re is present in the CRB in a readily leachable form, most of the Tc/Re deposited in the refractory is retained in the form of a durable glass phase.In addition to the direct penetration into the porous CRB, the molten salts from the LAW, mainly sulfates, chlorides, and nitrates, begin to evaporate from BV feeds at temperatures below 800°C and condense on iv solid surfaces at temperatures below 530°C. The condensed salt readily wets and pe...

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“…The techniques and procedures used to sample, analyze, calculate, and estimate the relative uncertainty associated with the soluble fraction of Cs, Re, and 99 Tc contained in the CRB are described in Pierce et al (2004a). To limit duplication, only a brief summary of these techniques are provided here.…”

Section: Soluble Fraction Experimental Materials and Methodsmentioning

confidence: 99%

“…To limit duplication, only a brief summary of these techniques are provided here. Note the sampling and analysis plan discussed below and in Pierce et al (2004a) was not statistically designed. Also, all error values reported are 1σ uncertainties, unless other wise noted.…”

Section: Soluble Fraction Experimental Materials and Methodsmentioning

confidence: 99%

Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

Pierce¹,

McGrail²,

Bagaasen³

et al. 2005

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SummaryThe Hanford Site in southeastern Washington State has been used extensively to produce nuclear materials for the U. S. strategic defense arsenal by the U. S. Department of Energy (DOE). A large inventory of radioactive and mixed waste has accumulated in 177 single-and double-shell tanks. Waste recovered from the tanks will be pre-treated to separate the low-activity fraction from the high-level and transuranic wastes. The low-activity fraction will be among the largest volumes of radioactive waste within the DOE complex and is one of the largest inventories of long-lived radionuclides planned for disposal in a low-level waste facility. Currently, the DOE Office of River Protection (ORP) is evaluating several options for immobilization of low-activity tank wastes for eventual disposal in a shallow subsurface facility at the Hanford Site. A significant portion of the waste will be converted into immobilized low-activity waste (ILAW) glass with a conventional Joule-heated ceramic melter. In addition to ILAW glass, DOE is considering a supplemental treatment technology; bulk vitrification (BV), to treat a portion of the low-activity waste (LAW). The use of a supplemental treatment technology is expected to accelerate the overall cleanup mission at the Hanford site by at least 35 years. CH2M Hill Hanford Group, Inc. A critical component of the development and testing strategy will be to provide estimates of radionuclide release rates from the engineered portion of the disposal facilities (source term). These data will be used for Subsurface Transport Over Reactive Multi-phases (STORM) simulations of the BV waste package. Documented in this report are data related to 1) kinetic rate law parameters for glass and refractory dissolution, 2) sodium (Na + )-hydrogen (H + ) ion exchange rate, 3) chemical reaction network of secondary phases that form in accelerated weathering tests, and 4) thermodynamic equilibrium constants assigned to these secondary phases for BV vitrified product. The kinetic rate law and Na + -H + ion exchange rate were determined from single-pass flow-through (SPFT) experiments. Product consistency (PCT) tests were used for accelerated weathering or aging of the glasses to determine a chemical reaction network of secondary phases that form. The majority of the thermodynamic data used in this data package were extracted from the thermodynamic database package provided with the geochemical code EQ3/6, version 8.0.Results from SPFT tests suggest that rate law parameters derived for BV glasses are comparable to those determined for WTP glass formulations. SPFT tests also were used to calculate a bounding release rate for the mullite castable refractory block (CRB). The presence of multiple mineral phases in and the uncertainty regarding the true reactive surface area of the CRB may have a significant effect on the reported rates. Therefore, we recommend that rate law parameters be developed for the pure mineral phases identified in the CRB. These results should be combined with literature values to...

show abstract

Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

Pierce¹,

McGrail²,

Bagaasen³

et al. 2005

Self Cite

View full text Add to dashboard Cite

SummaryThe Hanford Site in southeastern Washington State has been used extensively to produce nuclear materials for the U. S. strategic defense arsenal by the U. S. Department of Energy (DOE). A large inventory of radioactive and mixed waste has accumulated in 177 single-and double-shell tanks. Waste recovered from the tanks will be pre-treated to separate the low-activity fraction from the high-level and transuranic wastes. The low-activity fraction will be among the largest volumes of radioactive waste within the DOE complex and is one of the largest inventories of long-lived radionuclides planned for disposal in a low-level waste facility. Currently, the DOE Office of River Protection (ORP) is evaluating several options for immobilization of low-activity tank wastes for eventual disposal in a shallow subsurface facility at the Hanford Site. A significant portion of the waste will be converted into immobilized low-activity waste (ILAW) glass with a conventional Joule-heated ceramic melter. In addition to ILAW glass, DOE is considering a supplemental treatment technology; bulk vitrification (BV), to treat a portion of the low-activity waste (LAW). The use of a supplemental treatment technology is expected to accelerate the overall cleanup mission at the Hanford site by at least 35 years. CH2M Hill Hanford Group, Inc. A critical component of the development and testing strategy will be to provide estimates of radionuclide release rates from the engineered portion of the disposal facilities (source term). These data will be used for Subsurface Transport Over Reactive Multi-phases (STORM) simulations of the BV waste package. Documented in this report are data related to 1) kinetic rate law parameters for glass and refractory dissolution, 2) sodium (Na + )-hydrogen (H + ) ion exchange rate, 3) chemical reaction network of secondary phases that form in accelerated weathering tests, and 4) thermodynamic equilibrium constants assigned to these secondary phases for BV vitrified product. The kinetic rate law and Na + -H + ion exchange rate were determined from single-pass flow-through (SPFT) experiments. Product consistency (PCT) tests were used for accelerated weathering or aging of the glasses to determine a chemical reaction network of secondary phases that form. The majority of the thermodynamic data used in this data package were extracted from the thermodynamic database package provided with the geochemical code EQ3/6, version 8.0.Results from SPFT tests suggest that rate law parameters derived for BV glasses are comparable to those determined for WTP glass formulations. SPFT tests also were used to calculate a bounding release rate for the mullite castable refractory block (CRB). The presence of multiple mineral phases in and the uncertainty regarding the true reactive surface area of the CRB may have a significant effect on the reported rates. Therefore, we recommend that rate law parameters be developed for the pure mineral phases identified in the CRB. These results should be combined with literature values to...

show abstract

Progress Report on the Laboratory Testing of the Bulk Vitrification Cast Refractory

Cited by 4 publications

References 5 publications

Bulk Vitrification Castable Refractory Block Protection Study

Bulk Vitrification Castable Refractory Block Protection Study

Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

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