Impact of radiation chemistry on surface processes in LWRs

Forskningsprojekt, 2022 – 2024

n this project, the mechanisms behind corrosion, oxide deposition and oxide release in nuclear reactor systems will be studied with particular emphasis on the role of water radiolysis. The aim of the project is to identify situations where a simplified approach (not taking all aspects of water radiolysis into account) can be sufficient to mimic the surface processes and situations where this is not sufficient.

Surface reactions such as metal corrosion, oxide deposition and oxide release/dissolution are processes that have significant impact on the performance of and occupational safety around nuclear reactors. These processes are largely governed by the fairly harsh conditions prevailing inside a nuclear reactor. These conditions include high temperatures, high pressures, intense neutron fluxes and intense gamma fluxes.The primary oxidative radiolysis products in gamma-irradiated water are hydrogen peroxide (H2O2), the hydroxyl radical (HO•) and to some extent also the hydroperoxyl radical (HOO•). Molecular oxygen (O2) is subsequently formed as a secondary oxidative radiolysis product. These products may react with metal and metal oxide surfaces either by redox reactions or via surface catalyzed decomposition. The redox reactions lead to corrosion of the surfaces and the oxides formed may subsequently be dissolved and released to the coolant water. The dissolved corrosion products may deposit on other system surfaces, in particular heat-exchanging surfaces, and form crud.