Effects of on the kinetics of UO2 oxidation by H2O2

Hossain, Mohammad Mohsin; Ekeroth, Ella; Jönsson, Mats

doi:10.1016/j.jnucmat.2006.07.008

Cited by 68 publications

(94 citation statements)

References 15 publications

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“…Hence, the first step in the mechanism is rate limiting. The rate constant for the first step corresponds to a heterogeneous rate constant of 6 x 10 -7 m s -1 which is one order of magnitude higher than the second order rate constant for H 2 O 2 consumption reported in ref [40]. The rate constant used for the second step originates from an extrapolation of a relationship between the logarithm of the rate constant and the one-electron reduction potential of the oxidant.…”

Section: Oxidation Of Uo 2 (S)mentioning

confidence: 76%

“…For this reason, the rate constants cannot be considered to be the true rate constants for oxidation. In a more recent study, the kinetics of UO 2 oxidation by H 2 O 2 as a function of HCO 3 -concentration were studied [40]. The second order rate constant was found to increase linearly with HCO 3 -concentration from 0 to 1 mM.…”

Section: Oxidation Of Uo 2 (S)mentioning

confidence: 96%

“…To the best of our knowledge, second order rate constants for oxidation of UO 2 have only been reported in a very limited number of publications so far [39,40]. In reference [39] 6 2-.…”

Section: Oxidation Of Uo 2 (S)mentioning

confidence: 99%

“…In a relatively recent study, the rate constants for HCO 3 -facilitated dissolution of oxidized UO 2 (k = 1.7 x 10 -5 m s -1 ) and for dissolution of oxidized UO 2 in pure water (k = 7 x 10 -8 mol m -2 s -1 ) were reported [40]. These rate constants were determined indirectly from experimental studies of H 2 O 2 consumption.…”

Section: Dissolution Of Oxidized Uo 2 (S)mentioning

confidence: 99%

“…The concentration of H 2 will be many orders of magnitude higher but the reactivity is low and the reduction by H 2 often requires a catalyst. Numerous studies, aiming at elucidating the mechanistic details as well as the kinetics of radiation induced dissolution of UO 2 , have been performed [30][31][32][33][34][35][36][37][38][39][40][41][42]. Owing to the intrinsic complexity of the system, it has been difficult to draw general conclusions from studies on real spent nuclear fuel.…”

Section: Introductionmentioning

confidence: 99%

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Oxidation of UO2(s) in aqueous solution

Roth

Jönsson

2008

Open Chemistry

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Abstract:In this review the kinetics and mechanism of oxidative dissolution of UO 2 (s), mainly under conditions of relevance for the safety assessment of a deep geological repository for spent nuclear fuel, are discussed. Rate constants for the elementary processes involved (oxidation of UO 2 and dissolution of oxidized UO 2 ) are used to calculate the rates of oxidative UO 2 (s) dissolution under various conditions (type of oxidant, oxidant concentration and HCO 3 -/CO 3 2-concentration) for which experimental data are also available. The calculated rates are compared to the corresponding experimental values under the assumption that the experimental numbers reflect the steady-state conditions of the system. The agreement between the calculated rates and the corresponding experimental ones is very good, in particular for the higher rates. In general, the calculated rates are somewhat higher than the experimental numbers. This can be due partly to the use of initial concentrations rather than steady-state concentrations in the calculations. The kinetic data are also used to quantitatively discuss the dynamics of spent nuclear fuel dissolution under deep geological repository conditions. © Versita Warsaw and Springer-Verlag Berlin Heidelberg.

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Section: Oxidation Of Uo 2 (S)mentioning

confidence: 76%

Section: Oxidation Of Uo 2 (S)mentioning

confidence: 96%

“…To the best of our knowledge, second order rate constants for oxidation of UO 2 have only been reported in a very limited number of publications so far [39,40]. In reference [39] 6 2-.…”

Section: Oxidation Of Uo 2 (S)mentioning

confidence: 99%

Section: Dissolution Of Oxidized Uo 2 (S)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Oxidation of UO2(s) in aqueous solution

Roth

Jönsson

2008

Open Chemistry

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Impact of H₂ and Consecutive H₂O₂ Exposures on the Oxidative Dissolution of (U_1–xGd_x)O₂ Pellets Under Deep Repository Conditions for Spent Nuclear Fuel

2020

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The reactivity of H 2 O 2 towards (U 1-x Gd x )O 2 (x = 0.03, 0.045, 0.08) in the presence of H 2 was studied experimentally to assess the effect of H 2 on oxidative dissolution of Gd-doped UO 2 under deep repository conditions for spent nuclear fuel. Gd-doped UO 2 was chosen as a model substance for spent nuclear fuel due to its chemical similarity but low radiotoxicity. While H 2 O 2 is a radiolysis product capable of driving fuel matrix dissolution, H 2 , which is expected to evolve mainly through the corrosion of cast iron canisters encapsulating the fuel, might 157 Gd have high neutron cross-sections and can be introduced into the reactor core as burnable absorbers by doping standard UO 2 fuel. In addition, Gd builds up as a fission product in minor quantities in nuclear fuel during in-reactor irradiation. Therefore, Gd-doped UO 2 is part of the nuclear fuel cycle and after being discarded from the nuclear reactor it will eventually be stored in a deep geological repository according to the current plans in many countries. [3] After being discarded from a nuclear reactor, used fuel still consists mainly of UO 2 with small fractions (approx. 5 %) of highly radioactive fission products and heavier actinides that are present in different forms within the fuel matrix. [4,5] Among [a] Dr.

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H₂O₂‐Induced Oxidative Dissolution of UO₂ in Saline Solutions

Jamal

Jönsson

2021

Eur J Inorg Chem

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H2O2 is one of the oxidants responsible for driving the process of radiation‐induced dissolution of spent nuclear fuel in geological repositories for spent nuclear fuel. As the groundwater composition will vary depending on geographical location as well as on the age of the repository (in relation to glacial cycles, etc.), it is important to elucidate the impact of different groundwater constituents. While several studies have addressed the impact of HCO3− and halide ions on the radiation chemistry of water in general and radiation‐induced oxidative dissolution of spent nuclear fuel in particular, very few studies have addressed the impact of halide ions on the mechanism of the reaction between H2O2 and UO2. In this work, the impact of Cl−, Br− and ClO4− on the mechanism and kinetics of H2O2‐induced oxidative dissolution of UO2‐powder in aqueous suspensions with and without added HCO3− has been studied experimentally. The experiments reveal both ionic strength effects and specific ion effects on the kinetics of the reactions involved. These are discussed in connection to the results.

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Effects of on the kinetics of UO2 oxidation by H2O2

Cited by 68 publications

References 15 publications

Oxidation of UO2(s) in aqueous solution

Oxidation of UO2(s) in aqueous solution

Impact of H₂ and Consecutive H₂O₂ Exposures on the Oxidative Dissolution of (U_1–xGd_x)O₂ Pellets Under Deep Repository Conditions for Spent Nuclear Fuel

H₂O₂‐Induced Oxidative Dissolution of UO₂ in Saline Solutions

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Effects of on the kinetics of UO2 oxidation by H2O2

Cited by 68 publications

References 15 publications

Oxidation of UO2(s) in aqueous solution

Oxidation of UO2(s) in aqueous solution

Impact of H2 and Consecutive H2O2 Exposures on the Oxidative Dissolution of (U1–xGdx)O2 Pellets Under Deep Repository Conditions for Spent Nuclear Fuel

H2O2‐Induced Oxidative Dissolution of UO2 in Saline Solutions

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Impact of H₂ and Consecutive H₂O₂ Exposures on the Oxidative Dissolution of (U_1–xGd_x)O₂ Pellets Under Deep Repository Conditions for Spent Nuclear Fuel

H₂O₂‐Induced Oxidative Dissolution of UO₂ in Saline Solutions