Local Structures and Electronic States of C-S-H–Sodium–H<sub>2</sub>O Interface: NMR and DFT Studies

Tachikawa, Hiroto; Haga, Kazuko; Watanabe, Shuichi; Yamada, Kazuo

doi:10.1021/acs.jpcc.9b11302

Cited by 10 publications

(5 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Calcium silicate hydrate (C-S-H) is the most significant cement hydrate phase that interacts with Cs, and these interactions have been investigated extensively (Missan et al 2018;). These interactions have also been studied using atomistic models that considered molecular dynamics or quantum chemistry (Arayro et al 2018;Jian et al 2017;Duque-Redondo et al 2018;Tachikawa et al 2020). The contribution of aggregates in concrete has also been considered (Idemitsu et al 1992;Fuller et al 2014).…”

Section: Discussionmentioning

confidence: 99%

Cement and Concrete for Nuclear Waste Management

Nakarai¹,

Kosakowski²

2022

ACT

View full text Add to dashboard Cite

The safe management and disposal of radioactive wastes are of critical importance for maintaining a sustainable society. In nuclear waste management, cement and concrete are commonly used to immobilize radioactive waste. Cementation is a common technique used for conditioning low-level and intermediate-level radioactive wastes, which should ensure safe interim storage of waste packages, and act as a first long-term barrier during waste disposal. In addition, cement-based materials are utilized for construction and barrier materials in surface disposals for very low-level to low-level waste and deep geological disposals for low-level, intermediate-level, and high-level wastes.Furthermore, recovery from the nuclear disaster at the Fukushima Daiichi Nuclear Power Station (F1NPS) is an important and urgent issue in Japan. To solve the difficult problems associated with radioactive contaminated materials in the plant and in the environment, contributions of cement and concrete technologies are highly expected.The understanding end prediction of the long-term evolution of cement materials interacting with wastes and other barrier materials during interim and final storage is indispensable and needs to be studied by experts from different scientific and engineering disciplines. The very long times associated with the safe disposal of radioactive waste, which are well beyond the lifetime of ordinal engineered structures and therefore not experimentally accessible, make this task even more demanding.In the first part of this special issue, three technical contributions summarize research and development projects for nuclear waste management with cement and concrete technologies in Japan. and Ichikawa and Hamamoto (19-1275) give general overviews on the use of cement-based materials for low-level radioactive waste (LLW) and for high-level radioactive waste (HLW), respectively. Furthermore, Abe and Iida (20-236) present a comparative discussion of approaches used for LLW in Japan and Belgium.In the second part, the contributions concentrate on processes and applications related to the performance assessment of cement and concrete for nuclear waste management. The scientific papers describe sorption experiments with Cl, I, HTO, and C by Nedyalkova et al. (19-811), diffusion experiments with NaCl of leached cement paste by Kurmisawa et al. (19-426), leaching experiments of cement paste with quick setting admixture by Yokozeki et al. (19-1173), immersion experiments of cement-bentonite samples by Nakarai et al. (19-433, 19-447), and chemo-mechanical modelling of degraded concrete by Oda et al. (19-1075).Finally, the third part contains contributions that investigate, in a broad sense, how cement and concrete technologies can be used to deal with the aftermath of the F1NPS nuclear disaster. At first, a technical paper by summarizes the outcome of a research initiative that aimed at identifying the cause and extent of radioactive contamination of concrete at the F1NPS.A set of scientific contributions is related to water abso...

show abstract

Section: Discussionmentioning

confidence: 99%

Cement and Concrete for Nuclear Waste Management

Nakarai¹,

Kosakowski²

2022

ACT

View full text Add to dashboard Cite

show abstract

“…All calculations were performed using the Gaussian 09 software package . In previous studies, − we investigated the interaction between graphene and various molecules using DFT at the same level of theory. A similar technique was applied to the GR–Mg–(H 2 ) n system in this study.…”

Section: Methodsmentioning

confidence: 99%

Molecular Design of a Reversible Hydrogen Storage Device Composed of the Graphene Nanoflake–Magnesium–H₂ System

et al. 2021

Self Cite

View full text Add to dashboard Cite

Carbon materials such as graphene nanoflakes (GRs), carbon nanotubes, and fullerene can be widely used for hydrogen storage. In general, metal doping of these materials leads to an increase in their H2 storage density. In the present study, the binding energies of H2 to Mg species on GRs, GR–Mg m+ (m = 0–2), were calculated using density functional theory calculations. Mg has a wide range of atomic charges. In the case of GR–Mg (m = 0, Mg atom), the binding energy of one H2 molecule is close to 0, whereas those for m = 1 (Mg+) and 2 (Mg2+) are 0.23 and 13.2 kcal/mol (n = 1), respectively. These features suggest that GR–Mg2+ has a strong binding affinity toward H2, whereas GR–Mg+ has a weak binding energy. In addition, it was found that the first coordination shell is saturated by four H2 molecules, GR–Mg2+–(H2) n (n = 4). Next, direct ab initio molecular dynamics calculations were carried out for the electron-capture process of GR–Mg2+–(H2) n and a hole-capture process of GR–Mg+–(H2) n (n = 4). After electron capture, the H2 molecules left and dissociated from GR–Mg+: GR–Mg2+–(H2) n + e– → GR–Mg+ + (H2) n (H2 is released into the gas phase). In contrast, the H2 molecules were bound again to GR–Mg2+ after the hole capture of GR–Mg+: GR–Mg+ + (H2) n (gas phase) + hole → GR–Mg2+–(H2) n . On the basis of these calculations, a model device with reversible H2 adsorption–desorption properties was designed. These results strongly suggest that the GR–Mg system is capable of H2 adsorption–desorption reversible storage.

show abstract

“…Calcium silicate hydrate (C-S-H) is the most significant cement hydrate phase that interacts with Cs, and these interactions have been investigated extensively (Missan et al 2018;Haga et al 2019). These interactions have also been studied using atomistic models that considered molecular dynamics or quantum chemistry (Arayro et al 2018;Jian et al 2017;Duque-Redondo et al 2018;Tachikawa et al 2020). The contribution of aggregates in concrete has also been considered (Idemitsu et al 1992;Fuller et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Experimental Study Investigating the Effects of Concrete Conditions on the Penetration Behaviors of Cs and Sr at Low Concentration Ranges

Yamada

Igarashi

Osawa³

et al. 2021

ACT

Self Cite

View full text Add to dashboard Cite

To decommission of the Fukushima-Daiichi nuclear power plant after the reactor accident, it is important to estimate the distribution of radionuclide contamination in the concrete for key elements such as Cs and Sr. A reaction transport model will be developed for these calculations. However, for a realistic model, the behaviors of Cs and Sr penetration in concrete must be experimentally investigated. A part of the results of a MEXT project called "The Analysis of Radionuclide Contamination Mechanisms of Concrete and the Estimation of Contamination Distribution at the Fukushima Daiichi Nuclear Power Station" are presented in this technical report. From our penetration analyses, the behaviors of neither Cs nor Sr were affected by each other. Additionally, the apparent diffusion coefficients of Cs and Sr were not significantly affected by the concentration or the presence of clay in the mortars. The penetration depth of Sr was smaller than that of Cs, and fly ash blended cement increased the resistance to penetration compared with ordinary Portland cement. Carbonation in the mortar samples increased the adsorption of Cs especially. Sr interacted with cement hydrates more than with clays. In oven-dried mortars, under the condition of water suction, the presence of clay retarded Cs penetration but had no effect on Sr. When the mortars were carbonated and oven-dried, the interactions between the solid phase and Cs or Sr took hours at least to complete.

show abstract

Local Structures and Electronic States of C-S-H–Sodium–H₂O Interface: NMR and DFT Studies

Cited by 10 publications

References 24 publications

Cement and Concrete for Nuclear Waste Management

Cement and Concrete for Nuclear Waste Management

Molecular Design of a Reversible Hydrogen Storage Device Composed of the Graphene Nanoflake–Magnesium–H₂ System

Experimental Study Investigating the Effects of Concrete Conditions on the Penetration Behaviors of Cs and Sr at Low Concentration Ranges

Contact Info

Product

Resources

About

Local Structures and Electronic States of C-S-H–Sodium–H2O Interface: NMR and DFT Studies

Cited by 10 publications

References 24 publications

Cement and Concrete for Nuclear Waste Management

Cement and Concrete for Nuclear Waste Management

Molecular Design of a Reversible Hydrogen Storage Device Composed of the Graphene Nanoflake–Magnesium–H2 System

Experimental Study Investigating the Effects of Concrete Conditions on the Penetration Behaviors of Cs and Sr at Low Concentration Ranges

Contact Info

Product

Resources

About

Local Structures and Electronic States of C-S-H–Sodium–H₂O Interface: NMR and DFT Studies

Molecular Design of a Reversible Hydrogen Storage Device Composed of the Graphene Nanoflake–Magnesium–H₂ System