On the Oxidation of Plutonium (III) by Hydrogen Peroxide–Probable Formation of an Unstable Plutonium (III) Peroxy Complex

Mazumdar, Abhijit; Vaidyanathan, S.

doi:10.1524/ract.1973.19.4.165

Cited by 6 publications

(2 citation statements)

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“…It is evident from the above equilibria that what was once a single valency Pu(IV) system progressively becomes a multivalency system reflective of eq , containing Pu(III), Pu(IV), Pu(V), and Pu(VI) in various proportions. All of these plutonium oxidation states have been found to interact with the radiolysis products of aqueous HNO 3 to some extent. ,− H 2 O 2 plays a significant role in determining the radiolytic yield of HNO 2 and can also be slowly reduced by Pu(III) and oxidized by Pu(IV) and Pu(VI) (reactions –). ,, …”

Section: Discussionmentioning

confidence: 87%

Plutonium and Americium Alpha Radiolysis of Nitric Acid Solutions

et al. 2017

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The yield of HNO, as a function of absorbed dose and HNO concentration, from the α-radiolysis of aerated HNO solutions containing plutonium or americium has been investigated. There are significant differences in the yields measured from solutions of the two different radionuclides. For 0.1 mol dm HNO solutions, the radiolytic yield of HNO produced by americium α-decay is below the detection limit, whereas for plutonium α-decay the yield is considerably greater than that found previously for γ-radiolysis. The differences between the solutions of the two radionuclides are a consequence of redox reactions involving plutonium and the products of aqueous HNO radiolysis, in particular HO and HNO and its precursors. This radiation chemical behavior is HNO concentration dependent with the differences between plutonium and americium α-radiolysis decreasing with increasing HNO concentration. This change may be interpreted as a combination of α-radiolysis direct effects and acidity influencing the plutonium oxidation state distribution, which in turn affects the radiation chemistry of the system.

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Section: Discussionmentioning

confidence: 87%

Plutonium and Americium Alpha Radiolysis of Nitric Acid Solutions

et al. 2017

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“…Despite these implications, few irradiation studies can be found in the literature, and these are essentially limited to the impact of plutonium oxidation states on the yields of radiolysis products accompanied by mechanistic speculation. − Although these data have been useful for the construction of empirical and stochastic models, they are insufficient for the development of a predictive, mechanistic, multiscale model. Multiscale models for radiation effects are important as they capture the fundamental chemistry of an irradiated system from the point of energy deposition, through the lifetime of the nonhomogeneous radiation track (microseconds in water), and into bulk homogeneous solution (steady state).…”

Section: Introductionmentioning

confidence: 99%

Multiscale Modeling of Plutonium Radiation Chemistry in Nitric Acid Solutions. 1. Cobalt-60 Gamma Irradiation of Pu(IV)

Kynman,

Grimes,

Conrad

et al. 2024

Inorg. Chem.

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Careful manipulation of the plutonium oxidation states is essential in the study and utilization of its rich redox chemistry. To achieve this level of control, a comprehensive mechanistic understanding of radiation-induced plutonium redox chemistry is critical due to the unavoidable exposure of plutonium to ionizing radiation fields, both inherent and from in-process applications. To this end, we have developed an experimentally evaluated multiscale computer model for the prediction of gamma radiation-induced Pu(IV) redox chemistry in concentrated nitric acid solutions (1.0, 3.0, and 6.0 M). Under these acidic, aqueous solution conditions, cobalt-60 gamma irradiation afforded marginal net conversion of Pu(IV) to Pu(VI), the extent of which was dependent on the concentration of HNO 3 and absorbed gamma dose. Multiscale calculations, which are in excellent agreement with experimental data, indicate that this observation is due to a combination of inherent plutonium disproportionation reactions and several radiation-induced processes, including redox cycling between Pu(IV) and Pu(III), as achieved by the reduction of Pu(IV) by nitrous acid and hydrogen peroxide, the oxidation of Pu(III) by nitrate and hydroxyl radicals, and the sequential oxidation of Pu(IV) to Pu(V) and Pu(VI) by the remaining available yield of nitrate radicals.

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