A comprehensive multiscale model determines the fundamental reaction mechanisms of the radical-induced degradation of acetohydroxamic acid in acidic aqueous solutions.

The freeze-cast ceramics process involves the use of an aqueous slurry in which ice acts as a fugitive template, providing control of the morphology of the resultant green body, which is then sintered. Here we report the role of various additives and procedures in tailoring the morphology of ice-templated, freeze-cast alumina ceramics. We show that zirconium acetate (ZrAc) in the slurry can change the structure from lamellar to columnar, whereas polyvinyl alcohol can act as both a binder and as a modifier of the ice surface, and can compete with ZrAc to provide cooperative effects and a wide range of porosities. We also show that the ceramic structure can be influenced by epitaxial growth on an oriented layer of ice. K E Y W O R D Sgel casting, pores/porosity, processing

Ln(iii) complexation by TODGA led to enhanced chemical reactivity with RH˙+ from electron pulse irradiation. Average local ionization energy calculations indicate that this enhancement is likely due to preferential reaction at nitrate counter ions.

Pulse radiolysis with a custom multichannel detection system has been used to measure the kinetics of the radiation chemistry reactions of aqueous solutions of chromium(VI) to 325 °C for the first time. Kinetic traces were measured simultaneously over a range of wavelengths and fit to obtain the associated high-temperature rate coefficients and Arrhenius parameters for the reactions of Cr(VI) + e aq − , Cr(VI) + H • , and Cr(V) + • OH. These kinetic parameters can be used to predict the behavior of toxic Cr(VI) in models of aqueous systems for applications in nuclear technology, industrial wastewater treatment, and chemical dosimetry.

The first reported Raman spectra and ionization constants for the phosphate ion in H2O and D2O above 50 °C quantify deuterium isotope effects under hydrothermal conditions.

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Corrosion of aluminium alloy clad nuclear fuel, during reactor operation and under subsequent wet storage conditions, promotes the formation of aluminium hydroxide and oxyhydroxide layers. These hydrated mineral phases and the chemisorbed and physisorbed waters on their surfaces are susceptible to radiation-induced processes that yield molecular hydrogen gas (H2), which has the potential to complicate the long-term storage and disposal of aluminium clad nuclear fuel through flammable and explosive gas mixture formation, alloy embrittlement, and pressurization. Here, we present a systematic study of the radiolytic formation of H2 from aluminium alloy 1100 (AA1100) and 6061 (AA6061) coupons in “dry” (~0% relative humidity) and “wet” (50% relative humidity) helium environments. Cobalt-60 gamma irradiation of both aluminium alloy types promoted the formation of H2, which increased linearly up to ~2 MGy, and afforded G-values of 1.1 ± 0.1 and 2.9 ± 0.1 for “dry” and “wet” AA1100, and 2.7 ± 0.1 and 1.7 ± 0.1 for “dry” and “wet” AA6061. The negative correlation of H2 production with relative humidity for AA6061 is in stark contrast to AA1100 and is attributed to differences in the extent of corrosion and varying amounts of adsorbed water in the two alloys, as characterized using optical profilometry, scanning electron microscopy, Raman spectroscopy, and X-ray diffraction techniques.

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