Estimation of the Behaviors of Selenium in the Near Field of Repository

Kim, Seung-Soo; Min, Jin‐Young; Baik, Min Hoon; Kim, Gye Nam; Choi, Jongwon

doi:10.5516/net.06.2012.010

Cited by 3 publications

(6 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In Figure 1 The sorption tendency was also in agreement with the previous one [12]. The dominant sorption mechanism of Se(IV) onto goethite has been reported to be innersphere surface complexation [12,52,69]. The results of the current study can also be explained by inner-sphere surface complexation.…”

Section: Sorption Behavior Of Se(iv)supporting

confidence: 89%

“…The sorption of Se(IV) onto ≡FeOH sites can be described as inner-sphere surface complexation [12,22,27,52,69]. Biotite includes aluminol (≡AlOH) and silanol (≡SiOH) sites on the edge surfaces, in addition to ≡FeOH sites [3].…”

Section: Sorption Behavior Of Se (Iv)mentioning

confidence: 99%

“…The K int Cl value, which was not reported by Hayes et al [12] is in the range of 6.4-9.0 in the literatures [3,52,70,[72][73][74]; the intermediate value of 8.0 reported by Fukushi and Sverjensky [50] was adopted. The model parameters are summarized in Table 10.…”

Section: Sorption Behavior Of Se (Iv)mentioning

confidence: 99%

“…The dominant surface species predicted by the TLM were an innersphere complex (≡FeHSeO 3 0 ) at pH < 9 and an outersphere complex (≡FeOH 2 + − SeO 3 2− ) at pH > 10. In contrast to Se(IV) and Se(VI), the data of Se(−II) are scarce [9,13,52] and the sorption mechanisms of Se(−II) are poorly understood. Although the exact speciation of selenium in the vitrified HLW waste is unclear, it is estimated as Se(IV) or Se(VI) because selenium is exposed to oxidizing conditions during the reprocessing of spent fuel, and SeO 3 2− and SeO 4 2− can substitute trigonal borate or tetrahedral silicate entities, respectively, in the glass network [53][54][55][56].…”

mentioning

confidence: 99%

See 3 more Smart Citations

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Iida

Yamaguchi

Tanaka

2013

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

The sorption behavior of selenium onto iron-containing minerals such as goethite, ferrous oxide, magnetite, and biotite under reducing conditions were investigated by batch sorption experiments. Selenium was spiked as HSe − and Se 4 2− in the experimental solutions and reducing conditions were maintained throughout the sorption periods. The sorption behaviors of HSe − were analyzed by the triple-layer surface complexation model with the Visual Minteq computer program. The sorption data and the model calculations suggested that the dominant sorption mechanisms of HSe − were inner-sphere surface complexation for goethite and ferrous oxide but outer-sphere surface complexation for magnetite and biotite. The intrinsic equilibrium constant of the inner-sphere surface complexation reaction of HSe − with goethite, logK int HSe = 6.0, was determined by the fitting to the experimental results. The value of the equilibrium constant for outer-sphere complexation for magnetite and biotite was estimated to be around 12.

show abstract

Section: Sorption Behavior Of Se(iv)supporting

confidence: 89%

Section: Sorption Behavior Of Se (Iv)mentioning

confidence: 99%

Section: Sorption Behavior Of Se (Iv)mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Sorption behavior of hydroselenide (HSe⁻) onto iron-containing minerals

Iida

Yamaguchi

Tanaka

2013

Journal of Nuclear Science and Technology

View full text Add to dashboard Cite

show abstract

“…Previous investigations on Se immobilization with corrosion products have focused mostly on Se(IV) and Se(VI), but anoxic conditions in the subsurface, coupled with the reducing conditions imposed by H 2 generation during steel corrosion, are likely to keep Se in the −II oxidation state. It is commonly assumed, based on thermodynamics, that iron selenides control Se(−II) concentrations at reducing and ferruginous conditions. − Most studies of Se(−II) have thus focused on “secondary” immobilization reactions with iron oxides and sulfides, assuming Se concentrations close to equilibrium with iron selenides; − but fundamental information about the primary reactions forming iron selenides is scarce. Specifically, what role does Se(−II) coprecipitation and its interactions with transient, metastable corrosion products like Fe(OH) 2 play in initial immobilization?…”

Section: Introductionmentioning

confidence: 99%

Selenide [Se(−II)] Immobilization in Anoxic, Fe(II)-Rich Environments: Coprecipitation and Behavior during Phase Transformations

Francisco

Matsumura

Kikuchi

et al. 2022

Environ. Sci. Technol.

View full text Add to dashboard Cite

The radionuclide selenium-79 (Se-79) is predicted to be a key contributor to the long-term radiologic hazards associated with geological high-level waste (HLW) repositories; hence its release is of pertinent concern in the safety assessment of repositories. However, interactions of reduced Se species with aqueous Fe(II) species and solid phases arising from the corrosion of a steel overpack could play a role in mitigating its migration to the surrounding environment. In this study, we examined the immobilization mechanisms of Se(−II) during its interaction with aqueous Fe(II) and freshly precipitated Fe(OH)2 at circumneutral and alkaline conditions, respectively, its response to changes in pH, and its behavior during aging at 90 °C. Using microscopic and spectroscopic techniques, we observed β-FeSe precipitation, regardless of whether Se(−II) reacts with aqueous species or solid phases, and that modifying the pH following initial immobilization did not remobilize Se(−II). These observations indicate that Se(−II) migration beyond the overpack can be effectively and rapidly retarded via interactions with Fe(II) species arising from overpack corrosion. Thermodynamic calculations, however, showed that iron selenides became metastable at alkaline conditions and will dissolve in the long term. Aging experiments at 90 °C showed that Se(−II) can be completely retained via the crystallization of ferroselite at circumneutral conditions, while it will be largely remobilized at alkaline conditions. Our results show that Se(−II) mobility can be significantly influenced by its interactions with the corrosion products of the steel overpack and that these behaviors will have to be considered in repository safety assessments.

show abstract