Performance Properties of Saltstone Produced Using SWPF Simulants

Harbour, John R.; Edwards, T. B.

doi:10.2172/973190

Cited by 5 publications

(9 citation statements)

References 5 publications

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“…Based on the temperature profile, the monolith reached temperatures of ~ 152°F (67°C) and then started to progressively decrease after the fourth day. This maximum temperature is slightly above the limit that SRNL staff suggests for temperatures that should not be exceeded during waste form curing to minimize thermal stress cracking and microstructure changes (Harbour and Edwards 2009; see Section 5.0 discussion). Also Langton (1998) found that prolonged curing at temperatures above 60°C is not advised; see discussion below in Section 5.2.…”

mentioning

confidence: 87%

“…Several studies on the impact of increasing the dissolved aluminum (generally aluminate AlO 2 -) in the liquid waste have been performed at SRNL (Harbour and Edwards 2009;Harbour et al 2007bHarbour et al , 2007cHarbour et al , 2008Harbour et al , 2009aHarbour et al , 2009bHarbour et al , 2009c. The results of these studies are discussed in Section 5.1.…”

Section: Identification Of Waste Constituents That Adversely Impact Wmentioning

confidence: 99%

“…The key factors that control the performance of the Cast Stone and Saltstone waste forms have been identified by Harbour and Edwards (2009) as follows: 1) the time/temperature profile for curing, 2) water-to-cementitious materials ratio, 3) aluminate concentration in the waste stream, and 4) wt% slag in the dry blend premix.…”

Section: • Compressive Strengthmentioning

confidence: 99%

“…At Savannah River, some tank waste process changes being considered would significantly increase the amount of dissolved Al in the waste; therefore, numerous studies Harbour et al 2007b, c;Harbour and Edwards 2009;Harbour et al 2009a, b, c) have been performed to quantify the effects of Al concentrations (and in some studies other variables such as percentage of BFS and Portland cement used at the expense of removing fly ash) used in the dry blend mix on Saltstone waste form production and subsequent performance. A summary of the findings follows.…”

mentioning

confidence: 99%

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Data Package for Secondary Waste Form Down-Selection—Cast Stone

Serne¹,

Westsik²

2011

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Executive SummaryThe objective of the data packages being generated for four potential waste forms for solidification/ stabilization of Hanford liquid secondary waste streams is to identify, evaluate, and summarize the existing information. This Cast Stone data package includes information available in the open literature and from data obtained from testing currently underway at Pacific Northwest National Laboratory (PNNL). As used at Hanford, the term Cast Stone describes a "grout"-based waste form made predominantly with fly ash and blast furnace slag (BFS) with lesser amounts of Portland cement as the starting dry blend. At Savannah River, this waste form is called Saltstone. The blend of grout reagents in Saltstone has been constant (45 weight percent [wt%] Grade 100 slag cement, 45 wt% Class F fly ash, and 10-wt% Type I/II Portland cement) since the Saltstone Disposal Facility began production in the early 1990s. At Hanford, some cementitious variants to Cast Stone have also been investigated, in which either the fly ash or the BFS is absent or replaced with another material. In this data package, these Cast Stone variants are included for completeness in the review. However, almost all the current Cast Stone waste form testing performed at PNNL uses a dry blend consisting of 47-wt% blast furnace slag (Grade 100), 45-wt% fly ash (Class F), and 8-wt% Portland cement (Type I/II). The sources of the three dry blend ingredients used at Hanford and Savannah River differ and may have subtle impacts on the physical and chemical attributes of the subsequent waste forms. The compositions of the secondary waste simulants used for the PNNL Cast Stone studies also differ from the simulants and actual wastes solidified at Savannah River; although both are caustic-, saline-and sodium-dominated solutions. The Hanford secondary waste simulants anion composition contains much less nitrate/nitrite than the waste streams solidified at Savannah River.Available literature on Cast Stone and Saltstone was reviewed with an emphasis on determining how Cast Stone and related grout waste forms performed in relationship to various criteria that will be used to decide whether a specific type of waste form meets acceptance criteria for disposal in the Integrated Disposal Facility (IDF) at Hanford. The draft waste acceptance criteria include the following requirements or targets:• acceptable leachate concentrations (less than the Universal Treatment Standards in 40 CFR 268) for Resource Conservation and Recovery Act (RCRA) metals using the Toxicity Characteristic Leach Procedure (TCLP) leach test• low bleed water criteria (i.e., no bleed water is tolerated after 28 days of curing)• low leachability index (LI) values for sodium (LI>6), technetium-99 (target LI>9) and iodine-129 (target LI>11)• minimum compressive strength of 500 psi (3.45 MPa).Other attributes of the Cast Stone process were compared with additional criteria, such as:• worker and public safety concerns• cost effectiveness versus other candidate waste forms in regard to ...

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mentioning

confidence: 87%

Section: Identification Of Waste Constituents That Adversely Impact Wmentioning

confidence: 99%

Section: • Compressive Strengthmentioning

confidence: 99%

mentioning

confidence: 99%

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Data Package for Secondary Waste Form Down-Selection—Cast Stone

Serne¹,

Westsik²

2011

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“…35 The first mix measured contained 85 wt % Big Brown Raw Class F Fly Ash and 15 wt % slag with the low aluminate simulant at a 0.60 water to powder ratio (Figure 4.18). The second mix contained 85 wt % Class C Fly Ash and 15 wt % slag with the low aluminate simulant (0.60 water to powder ratio) shown in Figure 4.19.…”

Section: Heat Generationmentioning

confidence: 99%

Solidification of the Hanford Law Waste Stream Produced as a Result of Near-Tank Continuous Sludge Leaching and Sodium Hydroxide Recovery

Reigel¹,

Johnson²,

Crawford³

et al. 2011

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Secondary Waste Form Down-Selection Data Package—DuraLith

Mattigod¹,

Westsik²

2011

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SummaryThe Hanford Site in southeast Washington State has 56 million gallons of radioactive and chemically hazardous wastes stored in 177 underground tanks (DOE 2010). The U.S. Department of Energy Office of River Protection, through its contractors, is constructing the Hanford Tank Waste Treatment and Immobilization Plant (WTP) to convert the radioactive and hazardous wastes into stable glass waste forms for disposal. Within the WTP, the pretreatment facility will receive the retrieved waste from the tank farms and separate it into two treated process streams. These waste streams will be vitrified, and the resulting waste canisters will be sent to offsite (high-level waste) and onsite (immobilized low-activity waste) repositories. As part of the pretreatment and immobilized low-activity waste processing, liquid secondary wastes will be generated that will be transferred to the Effluent Treatment Facility on the Hanford Site for further treatment. These liquid secondary wastes will be converted to stable solid waste forms that will be disposed of in the Integrated Disposal Facility.To support the selection of a waste form for the liquid secondary wastes from the WTP, Washington River Protection Solutions has initiated secondary waste form testing work at Pacific Northwest National Laboratory. In anticipation of a down-selection process for a waste form for the Solidification Treatment Unit to be added to the Effluent Treatment Facility, Pacific Northwest National Laboratory is developing data packages to support that down-selection. The objective of the data packages is to identify, evaluate, and summarize the existing information on the four waste forms being considered for stabilizing and solidifying the liquid secondary wastes. This data package developed for the DuraLith waste form includes information available in the open literature and from data obtained from testing currently underway.DuraLith is an alkali-activated geopolymer waste form developed by the Vitreous State Laboratory at The Catholic University of America (VSL-CUA) for encapsulating liquid radioactive waste. A DuraLith waste form developed for treating Hanford secondary waste liquids is prepared by alkali-activation of a mixture of ground blast furnace slag and metakaolin with sand used as a filler material.Based on optimization tests, solid waste loading of ~7.5% and ~14.7% has been achieved using the Hanford secondary waste S1 and S4 simulants, respectively. The Na loading in both cases is equivalent to ~6 M. Some of the critical parameters for the DuraLith process include hydrogen generation and heat evolution during activator solution preparation using the waste simulant, heat evolution during and after mixing the activator solution with the dry ingredients, and a working window of ~20 minutes to complete the pouring of the DuraLith mixture into molds. Results of the most recent testing indicated that the working window can be extended to ~30 minutes if 75 wt% of the binder components, namely, blast furnace slag and metakaolin are replace...

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Performance Properties of Saltstone Produced Using SWPF Simulants

Cited by 5 publications

References 5 publications

Data Package for Secondary Waste Form Down-Selection—Cast Stone

Data Package for Secondary Waste Form Down-Selection—Cast Stone

Solidification of the Hanford Law Waste Stream Produced as a Result of Near-Tank Continuous Sludge Leaching and Sodium Hydroxide Recovery

Secondary Waste Form Down-Selection Data Package—DuraLith

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