Technetium in the Hydrosphere and in the Geosphere

Lieser, Κ. H.; Bauscher, Ch.

doi:10.1524/ract.1988.4445.1.125

Cited by 43 publications

(28 citation statements)

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“…The behavior of plutonium may be controlled by the chemistry of Pu 4 +, PuQ2+, or PuO2 2 + depending on the redox potential of the solution. Under slightly reducing conditions where Pu(IV,V) dominate, important species will include Pu(OH) 4 The behavior of technetium is expected to be dominated by the chemistry of the highly soluble pertechnetate ion, TcO 4 -, which is not hydrolyzed [243,244], complexed, or sorbed onto mineral surfaces. Tc(IV) species may dominate under reducing conditions.…”

Section: 1mentioning

confidence: 99%

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The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

Ebert

1995

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Argonne National Lahoratory. wi1th facilitie, in the states of liiinois and Idaho. is owned by the united States govern lent, and operated by The Un diversity of Chicago under the provisions of a contract with thie department of Enery. DISCLAIM ER THE FFFECTS OF THE GLASS SURFACE AREA/SOLUTION VOLUME RATIO ON GLASS CORROSION: A CRITICAL REVIEW William L. Ebert ABSTRACTThis report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume (SA/V) ratio on the corrosion behavior of borosilicate waste glasses. The SA/V ratio affects the rate of glass corrosion through the extent of dilution ok corrosion products released from the glass into the leachate solution: glass corrosion products are diluted more in tests conducted at low SA/V ratios than they are in tests conducted at high SAN ratios. Differences in the solution chemistries generated in tests conducted at different SA/V ratios then affect the observed glass corrosion behavior. Corrosion of borosilicate waste glasses results in the dissolution of soluble components and the accumulation of sparingly soluble components in a layer on the surface of the corroding glass. Laboratory tests performed to distinguish the effects of the solution chemistry and the surface layer on the glass corrosion rate have shown the rate to be controlled primarily by the solution chemistry. Therefore, any testing parameter that affects the solution chemistry will also affect the glass corrosion rate. The results of static leach tests conducted to assess the effects of the SAN are discussed with regard to the effects of SAN on the solution chemistry. The effects of the SA/V ratio observed in static tests can be understood based on the effects of the solution chemistry on glass corrosion behavior. Test results show several remaining issues with regard to the long-term glass corrosion behavior: Can the SAN ratio be used as an accelerating parameter to characterize the advanced stages of glass corrosion relevant to long disposal times? Is the alteration of the glass surface the same in tests conducted at different SAN, and in tests conducted with monolithic and crushed glass samples? What are the effects of the SAN and the extent of glass corrosion on the disposition of released radionuclides? These issues will bear on the prediction of the long-term performance of waste glasses during storage. The results of an experimental program conducted at ANL to address these and other remaining issues regarding the effects of SA/V on glass corrosion are described. I 2 SUMMARYThis report reviews and summarizes the present state of knowledge regarding the effects of the glass surface area/solution volume ratio (SA/V) on the corrosion behavior of borosilicate waste glasses. The effects of the SA/ occur through dilution of corrosion products and through the effects of the corrosion products on the glass corrosion mechanism and rate. Therefore, the effects of the SA/V on glass corrosion are discussed in terms of the various effects of t...

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Section: 1mentioning

confidence: 99%

“…Reduction to U4+ may occur under mildly reducing conditions. U 4 + is more strongly complexed than The behavior of technetium is expected to be dominated by the chemistry of the highly soluble pertechnetate ion, TcO 4 -, which is not hydrolyzed [243,244], complexed, or sorbed onto mineral surfaces. Tc(IV) species may dominate under reducing conditions.…”

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confidence: 99%

The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

Ebert

1995

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“…Complexation of TcO Ϫ 4 with humic acid and other dissolved organic carbon is only possible when the Eh-value becomes negative (E 0 =Ϫ0.50 V for Tc(VII)/Tc(IV)), (Rößler et al, 2000). As noted by Lieser and Bauscher (1987) (Henrot, 1989). Literature reports therefore suggest that neither chemical nor biological factors have much impact on the generally high availability of 99 Tc in aerobic soils.…”

Section: Tc In Aerobic and Anaerobic Soilsmentioning

confidence: 96%

Soil availability, plant uptake and soil to plant transfer of 99Tc—A review

Bennett

Willey

2003

Journal of Environmental Radioactivity

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“…In another study, Bird and Lopata (1980), in which solutions containing only trace concentrations were used, noted no measurable pertechnetate adsorption by magnetite. Studies by Lieser and Bauscher (1988), in which groundwater was used, and Bostick et al (1990), in which simulant raffinate was used, also showed negligible adsorption of 99 Tc (K d : <0.1 to 3 mL/g). These observations were confirmed by Byegard et al (1992), who observed that magnetite, when tested in synthetic and natural groundwater matrices (containing relatively high concentrations of SO 4 ) under both oxic and anoxic conditions, showed relatively poor affinity for 99 Tc (K d : 0.3 to 1.3 mL/g).…”

Section: Oxide and Hydroxide Mineralsmentioning

confidence: 99%

“…Metallic copper and its oxides (Haq et al 1980), soils and soil minerals (Rancon 1988), cementitious forms (Atkins and Glasser 1990), various types of minerals (Couture and Seitz 1983, Fetter et al 1996, Gradev 1987, Kang et al 1999, Krumhansl 2003, Taylor 1990), organophilic clays (Bors et al 1994a), modified montmorillonites (Sazarashi et al 1995), and novel adsorbents (Kaplan et al 2000 have been tested and evaluated for their getter properties for radioiodine. A similar effort was conducted to identify suitable getters for 99 Tc (Balsley et al 1985, Balsley et al 1996, Balsley et al 1997, Byegard et al 1992, Cui and Eriksen 1996b, Ito and Kanno 1988, Kang et al 1999, Kang et al 1996, Krumhansl 2003, Kunze et al 1996, Liang et al 1996, Lieser and Bauscher, 1988, Moore 2003, Palmer and Meyer 1981, Strickert et al 1980, Viani 1999, Wellman et al 2006, Zhuang et al 1988). …”

Section: Gettersmentioning

confidence: 99%

Review of Potential Candidate Stabilization Technologies for Liquid and Solid Secondary Waste Streams

Pierce¹,

Mattigod²,

Westsik³

et al. 2010

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Executive SummaryPacific Northwest National Laboratory has initiated a waste-form testing program to support the longterm durability evaluation of a waste form for secondary wastes generated from the treatment and immobilization of Hanford radioactive tank wastes. The purpose of the work discussed in this report is to identify candidate stabilization technologies and getters that have the potential to successfully treat the secondary waste stream liquid effluent, mainly from off-gas scrubbers and spent solids, produced by the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Down-selection to the most promising stabilization processes/waste forms is needed to support the design of a solidification treatment unit (STU) to be added to the Effluent Treatment Facility (ETF). To support key decision processes, an initial screening of the secondary liquid waste forms must be completed by February 2010. Later, more comprehensive and longer term performance testing will be conducted, following the guidance provided by the secondary waste-form selection, development, and performance evaluation roadmap. The resulting waste form will be compliant to regulations and performance criteria and will lead to cost-effective disposal of the secondary wastes.This report starts with a brief review of some of the most commonly used solidification formulations that would be candidates for secondary liquid waste streams. In this review, the available data on performance are discussed, and some preliminary recommendations are provided for materials that should undergo additional screening testing. We also 1) discuss options for disposal of WTP secondary solid waste streams, 2) provide a brief overview of standard regulatory test methods used for measuring contaminant leachability and waste-form physical strength (with emphasis on the U.S. Environmental Protection Agency's [EPA's] new methods as a screening tool for comparing waste solidification materials of interest), and 3) provide an overview of factors that must be considered in long-term performance testing, including state-of-the-art characterization tools that can provide the data needed to technically defend predictive modeling simulations of long-term material behavior. The long-term wasteform testing and solid and leachate characterization must be robust enough to effectively predict material performance in the Integrated Disposal Facility over the 10,000-year period of performance for the engineered system. The solidification technologies for liquid waste streams include cement/grout, containerized Cast Stone, phosphate-bonded ceramics, alkali-aluminosilicate geopolymers, hydroceramics, L-TEM, and fluidized-bed steam reforming (FBSR). In addition to these, other mature technologies and two compounds, namely goethite and sodalite (that are still being developed), that show considerable promise as waste forms or getters are also discussed. It is our recommendation, based upon the available literature, that Cast Stone, chemically bonded phosphate ceramics (Ceramicrete...

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Technetium in the Hydrosphere and in the Geosphere

Cited by 43 publications

References 0 publications

The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

The effects of the glass surface area/solution volume ratio on glass corrosion: A critical review

Soil availability, plant uptake and soil to plant transfer of 99Tc—A review

Review of Potential Candidate Stabilization Technologies for Liquid and Solid Secondary Waste Streams

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