Technetium in the Nuclear Fuel Cycle, in Medicine and in the Environment

Lieser, Κ. H.

doi:10.1524/ract.1993.63.special-issue.5

Cited by 110 publications

(63 citation statements)

References 11 publications

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“…For all three resins, the K d values were lower in 2 M K 2 CO 3 regardless of pretreatment. This is consistent with the results in Figure 2, and indicates competition between TcO 4 − , OH − , and CO 3 2− for the available anion exchange sites. It should be noted that despite the double negative charge of the carbonate anions a nearly 1000-fold excess of carbonate is needed to significantly compete with TcO 4 − for ion exchange.…”

Section: ■ Results and Discussionsupporting

confidence: 92%

“…For this reason, Reillex HPQ was deemed unsuitable for further process development. Both Purolite A530E and Dowex Marathon WBA showed very low affinity for UO 2 (CO 3 ) 3 4− uptake, which could be used to separate technetium from uranium. The selectivity of TcO 4 − to UO 2 (CO 3 ) 3 4− uptake was determined to be 20 300 for Purolite A530E and 500 for Dowex Marathon WBA in 2 M K 2 CO 3 solutions.…”

Section: ■ Conclusionmentioning

confidence: 99%

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Anion Exchange Resins for the Selective Separation of Technetium from Uranium in Carbonate Solutions

Long

Goff

Ware

et al. 2012

Ind. Eng. Chem. Res.

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In alkaline carbonate solutions both technetium and uranium exist as anionic species, TcO 4 − and UO 2 (CO 3 ) 3 4− , which makes separating Tc and U from each other more challenging compared to acidic PUREX type solutions where uranium forms neutral or cationic complexes. We tested the batch separation of 99 Tc, 238 U, and 239 Pu from carbonate solutions using anion exchange resins with different properties, including Purolite A530E, Reillex HPQ, and Dowex Marathon WBA. Overall, the highest K d values for pertechnetate were achieved using the strong base resins in solutions of the lowest carbonate concentration. Pretreating the resins in higher carbonate concentrations before use was shown to increase the K d values for pertechnetate. The measured K d values for uranium generally were low, resulting in high selectivity for the separation of pertechnetate from uranium in carbonate solutions.

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Section: ■ Results and Discussionsupporting

confidence: 92%

Section: ■ Conclusionmentioning

confidence: 99%

Anion Exchange Resins for the Selective Separation of Technetium from Uranium in Carbonate Solutions

Long

Goff

Ware

et al. 2012

Ind. Eng. Chem. Res.

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show abstract

“…At pH 7, pertechnetate in soil can only be found at an E h >200 mV. If the E h drops below this value, the pertechnetate is reduced to TcO 2 , which has been clearly verified by sorption experiments with technetium in ground water/sediment systems [4]. Low redox potentials occur in water-logged soils or in compacted soils where the aeration is inhibited.…”

Section: Fate Of Long-lived Radionuclides In Soilmentioning

confidence: 80%

Considerations on the behaviour of long-lived radionuclides in the soil

Koch-Steindl

Pröhl²

2001

Radiation and Environmental Biophysics

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The migration of radionuclides from waste repositories to the biosphere potentially leads to a contamination of soil. Due to the importance of food production, the mobilisation and accumulation behaviour of long-lived radionuclides in the soil plays a key role in performance assessment studies. In this paper, the main features and processes that control radionuclide behaviour in soil, such as pH, redox potential and sorption to organic and inorganic soil components, are discussed for the radionuclides 36Cl, 79Se, 129I, 99Tc, 237Np and 238U, that are usually most relevant in long-term safety assessments of nuclear waste. The interaction of radionuclide behaviour in soil with environmental factors, such as temperature and humidity as well as farming practices are discussed. The possible impact of future soil development on long-term behaviour in soil are taken into consideration. Due to the physiological constraints of plant growth, appropriate soil conditions for growth will probably not be substantially different from current requirements, bearing in mind that sustainable agriculture strives for optimal plant growth. Against this background, present-day parameters may in general be considered appropriate for roughly estimating the behaviour of radionuclides in the soil-plant system.

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“…Technetium-99 is generated as a fission product during the irradiation of U-containing nuclear fuels, and has a half live (t 1/2 ) of 2.11 × 10 5 yr. The behavior of Tc in environmental systems has been reviewed extensively by Lieser (1993), Gu and Schulz (1991), Sparks and Long (1987), Meyer et al (1985), Beasley and Lorz (1984), Coughtrey et al (1983), Onishi et al (1981), Wildung et al (1979), Ames and Rai (1978), and others. Hughes and Rossotti (1987) review in detail the solution chemistry of Tc.…”

Section: Technetium-99mentioning

confidence: 99%

Advances in Geochemical Testing of Key Contaminants in Residual Hanford Tank Waste

Deutsch¹,

Krupka²,

Cantrell³

et al. 2005

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This document was printed on recycled paper.The cover shows a scanning electron microscope image of aluminum (red) and iron (green) in a particle aggregate of residual waste from tank C-106 at the C Tank Farm on the Hanford Site. Cover design by S. B. Neely, Pacific Northwest National Laboratory. SummaryThis report describes the advances that have been made over the past two years in testing and characterizing waste material in Hanford tanks. This waste is being studied because it will remain in the tanks after closure and represents a potential source of contamination to the environment. The development of a contaminant release model for the residual waste in a tank requires detailed knowledge of the composition of the waste and the phases (liquid and solids) in the waste that contain the contaminant. The contaminant release models developed for the tanks will be used as a component in the performance assessments for tank closures being conducted by CH2M HILL Hanford Group Inc. for the U.S. Department of Energy.

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Technetium in the Nuclear Fuel Cycle, in Medicine and in the Environment

Cited by 110 publications

References 11 publications

Anion Exchange Resins for the Selective Separation of Technetium from Uranium in Carbonate Solutions

Anion Exchange Resins for the Selective Separation of Technetium from Uranium in Carbonate Solutions

Considerations on the behaviour of long-lived radionuclides in the soil

Advances in Geochemical Testing of Key Contaminants in Residual Hanford Tank Waste

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