Application of Radiation Chemistry to Some Selected Technological Issues Related to the Development of Nuclear Energy

Abstract

The most important contributions of radiation chemistry to some selected technological issues related to water-cooled reactors, reprocessing of spent nuclear fuel and high-level radioactive wastes, and fuel evolution during final radioactive waste disposal are highlighted. Chemical reactions occurring at the operating temperatures and pressures of reactors and involving primary transients and stable products from water radiolysis are presented and discussed in terms of the kinetic parameters and radiation chemical yields. The knowledge of these parameters is essential since they serve as input data to the models of water radiolysis in the primary loop of light water reactors and super critical water reactors. Selected features of water radiolysis in heterogeneous systems, such as aqueous nanoparticle suspensions and slurries, ceramic oxides surfaces, nanoporous, and cement-based materials, are discussed. They are of particular concern in the primary cooling loops in nuclear reactors and long-term storage of nuclear waste in geological repositories. This also includes radiation-induced processes related to corrosion of cladding materials and copper-coated iron canisters, dissolution of spent nuclear fuel, and changes of bentonite clays properties. Radiation-induced processes affecting stability of solvents and solvent extraction ligands as well oxidation states of actinide metal ions during recycling of the spent nuclear fuel are also briefly summarized.

The Reaction of Muonium with Hydrogen Peroxide in Aqueous Solution

“…Again, pH can be important, as in the storage of nuclear waste in concrete canisters, where adsorbed water undergoes radiolysis in a high pH environment, due to the calcium hydroxide present in the cement-based materials. [26]…”

Molecular Dynamics Characterization of Dielectron Hydration in Liquid Water with Unique Double Proton Transfers

“…Radiolysis of aqueous environments is always a traditional and fascinating chemical problem because it has the fundamental interest and applications including interpreting numerous reaction mechanisms in various catalytic or nuclear reactions in aqueous systems. − Ionizing radiation in liquid water could produce major radiolysis products. − Hydrated electron (e – aq ), a unique electron entity and special reactive reductant among them, has been evidenced not only to exhibit some special properties but also to participate in various reactions including hydrogen evolution as initiator or catalyst, thus attracting researchers’ continuous attention for more than half a century. − Great progresses have been made on the structures, energies, spectra, and reactivity of solvated electrons in various media with some documented information. − However, questions on the radiation-induced hydrated electrons and other reactivity in aqueous solution still remain (Section S1 in the Supporting Information (SI)). For example, e – aq was experimentally assumed to connect with hydrogen evolution via a recombined form (e 2 2– aq ) as a hypothetical intermediate in interpreting the anti-Arrhenius behavior of the hydrogen evolution rate in radiolysis of water, − but the underlying mechanisms always lack direct evidence.…”

A mathematical model to describe the alpha dose rate from a UO2 surface

“…A consistent risk to the integrity of the fuel matrix is its exposure to water in the event of cladding failure. If exposed to water, spent fuel can undergo radiolytically assisted dissolution, releasing highly radioactive fission products into the local environment [4][5][6]. This could occur in long-term storage but is not expected (e.g.…”