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Impact of H 2 and Consecutive H 2 O 2 Exposures on the Oxidative Dissolution of (U 1– x Gd x )O 2 Pellets Under Deep Repository Conditions for Spent Nuclear Fuel
Author(s) -
Maier Annika Carolin,
Barreiro Fidalgo Alexandre,
Jonsson Mats
Publication year - 2020
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000133
Subject(s) - dissolution , chemistry , reactivity (psychology) , pellets , uranium dioxide , spent nuclear fuel , nuclear fuel , redox , nuclear chemistry , radiolysis , analytical chemistry (journal) , pellet , radiochemistry , inorganic chemistry , uranium , metallurgy , materials science , aqueous solution , environmental chemistry , medicine , alternative medicine , pathology , composite material
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 limit or even suppress fuel dissolution. Commercial (U 1– x Gd x )O 2 pellets were immersed in 10 m m HCO 3 – solutions and consecutively exposed to 2 m m H 2 O 2 in an autoclave under either 40 bar H 2 or 5 bar N 2 atmosphere. The results indicate that H 2 does not influence the oxidative dissolution of (U 1– x Gd x )O 2 . Instead, the reactivity of the pellets decreases with increasing H 2 O 2 exposure due to an irreversible alteration of the pellet surfaces resulting in decreased redox reactivity.