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Gamma radiation induces hydrogen absorption by copper in water.

Lousada CM, Soroka IL, Yagodzinskyy Y, Tarakina NV, Todoshchenko O, Hänninen H, Korzhavyi PA, Jonsson M - Sci Rep (2016)

Bottom Line: One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste.Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel.At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system.

View Article: PubMed Central - PubMed

Affiliation: Division of Materials Technology, Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.

ABSTRACT
One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

No MeSH data available.


Related in: MedlinePlus

Time scale of events in water radiolysis leading to the primary products: H2; HO•; H2O2; H3O+; HO−; H• and eaq−.
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f1: Time scale of events in water radiolysis leading to the primary products: H2; HO•; H2O2; H3O+; HO−; H• and eaq−.

Mentions: The consequences of the exposure of many homogeneous systems to ionizing radiation are well-known on the basis of both experimental and theoretical studies performed over a period close to a century15. However, most systems of practical relevance are not homogeneous. In fact, one of the most crucial and thereby also interesting components of a system from a performance perspective is the interface between two phases. In nuclear technology, interfaces exposed to ionizing radiation constitute a key-point in any safety assessment and a common theme is the impact of radiation-induced corrosion in nuclear power plants, nuclear fuel reprocessing plants and repositories for radioactive waste1617. In spite of the obvious importance of interfacial radiation chemistry, surprisingly, little is known about underlying mechanisms.To describe the radiation chemistry at an interface it is necessary to have information about: the homogeneous radiation chemistry of the two phases in contact; the energy deposition in the system; the yield of radiolysis products; and the reactivity of radiolysis products at the interface between the two homogeneous phases. γ-radiolysis of liquid water leads to a number of reactive species that are formed on different time scales18 as depicted in Fig. 1. The radiation chemical yield (G-value) of a product of γ-radiolysis of water may be affected by the presence of chemical species or materials in the aqueous medium19. Several studies have shown that the yield of the aqueous radiolysis product H2 can be significantly higher in water layers close to an oxide surface when compared to pure bulk water2021. The magnitude of this effect depends on the nature of the oxide. However, no convincing mechanistic explanation that accounts for these observations has been given. In addition to the somewhat puzzling observations regarding the radiation chemical yield of H2, a number of studies on the interactions between other aqueous radiolysis products and oxide surfaces have been presented. It has been shown that H2O2 is catalytically decomposed22 to O2 and H2O via the intermediate formation of hydroxyl radicals on most oxide surfaces, and that the hydroxyl radical has a high affinity for oxide surfaces23. Additionally, under certain conditions, the decomposition of H2O2 at oxide surfaces can also lead to the formation of H224.


Gamma radiation induces hydrogen absorption by copper in water.

Lousada CM, Soroka IL, Yagodzinskyy Y, Tarakina NV, Todoshchenko O, Hänninen H, Korzhavyi PA, Jonsson M - Sci Rep (2016)

Time scale of events in water radiolysis leading to the primary products: H2; HO•; H2O2; H3O+; HO−; H• and eaq−.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834571&req=5

f1: Time scale of events in water radiolysis leading to the primary products: H2; HO•; H2O2; H3O+; HO−; H• and eaq−.
Mentions: The consequences of the exposure of many homogeneous systems to ionizing radiation are well-known on the basis of both experimental and theoretical studies performed over a period close to a century15. However, most systems of practical relevance are not homogeneous. In fact, one of the most crucial and thereby also interesting components of a system from a performance perspective is the interface between two phases. In nuclear technology, interfaces exposed to ionizing radiation constitute a key-point in any safety assessment and a common theme is the impact of radiation-induced corrosion in nuclear power plants, nuclear fuel reprocessing plants and repositories for radioactive waste1617. In spite of the obvious importance of interfacial radiation chemistry, surprisingly, little is known about underlying mechanisms.To describe the radiation chemistry at an interface it is necessary to have information about: the homogeneous radiation chemistry of the two phases in contact; the energy deposition in the system; the yield of radiolysis products; and the reactivity of radiolysis products at the interface between the two homogeneous phases. γ-radiolysis of liquid water leads to a number of reactive species that are formed on different time scales18 as depicted in Fig. 1. The radiation chemical yield (G-value) of a product of γ-radiolysis of water may be affected by the presence of chemical species or materials in the aqueous medium19. Several studies have shown that the yield of the aqueous radiolysis product H2 can be significantly higher in water layers close to an oxide surface when compared to pure bulk water2021. The magnitude of this effect depends on the nature of the oxide. However, no convincing mechanistic explanation that accounts for these observations has been given. In addition to the somewhat puzzling observations regarding the radiation chemical yield of H2, a number of studies on the interactions between other aqueous radiolysis products and oxide surfaces have been presented. It has been shown that H2O2 is catalytically decomposed22 to O2 and H2O via the intermediate formation of hydroxyl radicals on most oxide surfaces, and that the hydroxyl radical has a high affinity for oxide surfaces23. Additionally, under certain conditions, the decomposition of H2O2 at oxide surfaces can also lead to the formation of H224.

Bottom Line: One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste.Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel.At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system.

View Article: PubMed Central - PubMed

Affiliation: Division of Materials Technology, Department of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden.

ABSTRACT
One of the most intricate issues of nuclear power is the long-term safety of repositories for radioactive waste. These repositories can have an impact on future generations for a period of time orders of magnitude longer than any known civilization. Several countries have considered copper as an outer corrosion barrier for canisters containing spent nuclear fuel. Among the many processes that must be considered in the safety assessments, radiation induced processes constitute a key-component. Here we show that copper metal immersed in water uptakes considerable amounts of hydrogen when exposed to γ-radiation. Additionally we show that the amount of hydrogen absorbed by copper depends on the total dose of radiation. At a dose of 69 kGy the uptake of hydrogen by metallic copper is 7 orders of magnitude higher than when the absorption is driven by H2(g) at a pressure of 1 atm in a non-irradiated dry system. Moreover, irradiation of copper in water causes corrosion of the metal and the formation of a variety of surface cavities, nanoparticle deposits, and islands of needle-shaped crystals. Hence, radiation enhanced uptake of hydrogen by spent nuclear fuel encapsulating materials should be taken into account in the safety assessments of nuclear waste repositories.

No MeSH data available.


Related in: MedlinePlus