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McCabe, D.

Publications and source records attributed to McCabe, D..

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Evaluation of Immobilizing Secondary Waste from a Proposed Treatment Process for Hanford WTP LAW Melter Condensate

The off-gas system in the Low Activity Waste (LAW) vitrification facility at the Hanford Waste Treatment and Immobilization Plant (WTP) will generate an aqueous condensate recycle stream. Two unit operations generate this condensate, a Submerged Bed Scrubber and a Wet Electrostatic Precipitator (LAW SBSWESP condensate). The expected 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 to immobilize the semivolatile 99 Tc isotope into the glass. During the Direct Feed Low Activity Waste (DFLAW) portion of the mission, the condensate is sent to the Effluent Management Facility (EMF) where it is evaporated then recycled to the LAW facility where the evaporated condensate is combined with the LAW feed from the pretreatment system.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Phase 2 testing results of immobilization of WTP effluent management facility vaporator bottoms simulant

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate) from the primary off-gas system. This work examined three waste form formulations based on previous testing with related simulants: 8 wt% ordinary portland cement (OPC), 47 wt% blast furnace slag (BFS), 45 wt% fly ash (FA) known as Cast Stone formulation; 20 wt% Aquaset® II-GH and 80 wt% BFS; 20 wt% OPC and 80 wt% BFS. These tests successfully produced one waste form that set within five days (Cast Stone formulation); however the other two formulations, Aquaset® II-GH/BFS and OPC/BFS, took approximately eight and fourteen days to set, respectively.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Preparation and evaporation of Hanford Waste treatment plant direct feed low activity waste effluent management facility simulant

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate, LMOGC) from the off-gas system. The baseline plan for disposition of this stream during full WTP 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. However, during the Direct Feed LAW (DFLAW) scenario, planned disposition of this stream involves concentrating the condensate in a new evaporator at the Effluent Management Facility (EMF) and returning it to the LAW melter. The LMOGC stream will contain components, e.g. halides and sulfates, that are volatile at melter temperatures, have limited solubility in glass waste forms, and present a material corrosion concern. Because this stream will recycle within WTP, these components are expected to accumulate in the LMOGC stream, exacerbating their impact on the number of LAW glass containers that must be produced. Diverting the stream reduces the halides and sulfates in the glass and is a key objective of this program. In order to determine the disposition path, it is key to experimentally determine the fate of contaminants. To do this, testing is needed to account for the buffering chemistry of the components, determine the achievable evaporation end point, identify insoluble solids that form, determine the formation and distribution of key regulatoryimpacting constituents, and generate an aqueous stream that can be used in testing of the subsequent immobilization step. This overall program examines the potential treatment and immobilization of the LMOGC stream to enable alternative disposal. The objective of this task was to (1) prepare a simulant of the LAW Melter Off-gas Condensate expected during DFLAW operations, (2) demonstrate evaporation in order to predict the final composition of the effluents from the EMF evaporator to aid in planning for their disposition, and (3) generate concentrated evaporator bottoms for use in immobilization testing.

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