Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

Adamson, Duane J.; Nash, C. A.; McCabe, Daniel J.; Crawford, Charles L.; Wilmarth, W.R.

doi:10.2172/1117838

Cited by 12 publications

(16 citation statements)

References 9 publications

(4 reference statements)

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“…More detail on the basis for and synthesis of the simulant has been documented. 5,6,9 1.2 Decontamination Process One option that has been previously evaluated is disposal of the LAW Off-Gas Condensate stream directly to the ETF, however, this option has a number of consequences to ETF including increases in waste volume, halide levels, and radioactivity.10 , 11 These have not been evaluated any further in this study, but it is recognized that this would have significant impacts that must be addressed by the facility.…”

Section: Simulant Formulation Basismentioning

confidence: 99%

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Investigation of variable compositions on the removal of technetium from Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

Taylor-Pashow

McCabe

Pareizs

2017

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The Low Activity Waste (LAW) vitrification facility at the Hanford Waste Treatment and Immobilization Plant (WTP) will generate an aqueous condensate recycle stream (LAW Off-Gas Condensate) from the offgas system. The plan for disposition of this stream during baseline operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility again. The primary reason to recycle this stream is so that the semi-volatile 99 Tc isotope eventually becomes incorporated into the glass. This stream also contains non-radioactive salt components that are problematic in the melter, so diversion of this stream to another process would eliminate recycling of these salts and would enable simplified operation of the LAW melter and the Pretreatment Facilities. This diversion from recycling this stream within WTP would have the effect of decreasing the LAW vitrification mission duration and quantity of glass waste. The concept being tested here involves removing the 99 Tc so that the decontaminated aqueous stream, with the problematic salts, can be disposed elsewhere. Technetium will not be removed from the aqueous tank waste during pretreatment in the Hanford WTP and will be sent to the LAW melter. It is intended that 99 Tc will be immobilized in the LAW glass. Because it is semi-volatile at melter temperatures and roughly 70% vaporizes, the only way to get it to stay in the glass is by repeated recycle into the LAW melter. Although other radionuclides are expected to be present in low concentration in the LAW Off-Gas Condensate, such as 129 I, 90 Sr, 137 Cs, 241 Pu, and 241 Am, it is the longlived and environmentally mobile 99 Tc that is the primary component of concern. This LAW Off-Gas Condensate stream originates from the Submerged Bed Scrubber (SBS) and the Wet Electrostatic Precipitator (WESP) from the LAW melter off-gas system. Pilot simulant tests indicate that this stream is expected to be a dilute salt solution with near neutral pH, and will likely contain some insoluble solids from melter carryover. The soluble salt components are expected to be mostly sodium and ammonium salts of nitrate, chloride, and fluoride. Although this stream has not yet been generated and will not be available until the WTP begins operation, a simulant has been produced based on models, calculations, and comparison with pilot-scale tests. SRNL-STI-2017-00087 Revision 0 vi that Hg(II) is reduced and removed from the aqueous phase upon addition of Sn(II). Conversely, no reaction was observed with nitrite ion. It was also observed that only trace amounts of hydrogen were generated in the reaction, even with a large excess of SnCl 2 , which will avoid flammable gas operational issues. Additionally, tests showed that perrhenate ion (ReO 4-) is not a suitable surrogate for pertechnetate, as it is not reduced by Sn(II) in this simulant. Another component of this program is to begin to mature the technology readiness of this process. A key component of that...

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Section: Simulant Formulation Basismentioning

confidence: 99%

“…Detail on the basis and synthesis of the simulant has been documented elsewhere, and is repeated here for completeness. 9 The target concentrations of chemicals were derived from the output from the HTWOS calculation, documented in SVF-2732. 8 Two different batches of simulant were used in the testing described in this report.…”

Section: Simulant Preparationmentioning

confidence: 99%

Investigation of variable compositions on the removal of technetium from Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

Taylor-Pashow

McCabe

Pareizs

2017

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“…The HTWOS model run scenario selected as the basis for the solution chemistry was full operation of all of the WTP facilities, including supplemental LAW melters (in the assumed second LAW facility (SLAW). More detail on the synthesis of the simulant used by Taylor-Pashow et al (2014a) has been documented in Adamson et al (2013) and McCabe et al (2013;Appendix A-1) gives selected output from the HTWOS SVF-2732 predictions. These HTWOS predictions are shown in the right side of Table 5-6.…”

Section: Srnl Studies On Off-gas Simulants For Fully Operational Wtpmentioning

confidence: 99%

Options for the Separation and Immobilization of Technetium

Serne¹,

Crum²,

Riley³

et al. 2016

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“…Other simulant formulations of the LMOGC have been prepared [3,4]. Those simulants were primarily based on the calculated output composition generated by the Hanford Tank Waste Operations Simulator (HTWOS), with adjustments based on pilot-scale test results.…”

Section: Previous Testing Basismentioning

confidence: 99%

Formulation and preparation of Hanford Waste Treatment Plant direct feed low activity waste Effluent Management Facility core simulant

McCabe¹,

Nash²,

Adamson³

2016

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Laboratory Evaporation Testing Of Hanford Waste Treatment Plant Low Activity Waste Off-Gas Condensate Simulant

Cited by 12 publications

References 9 publications

Investigation of variable compositions on the removal of technetium from Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

Investigation of variable compositions on the removal of technetium from Hanford Waste Treatment Plant low activity waste melter off-gas condensate simulant

Options for the Separation and Immobilization of Technetium

Formulation and preparation of Hanford Waste Treatment Plant direct feed low activity waste Effluent Management Facility core simulant

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