CHEMICAL AND MICROSTRUCTURAL ANALYSES TECHNIQUES FOR FUEL DEBRIS SIMULANTS AND AIRBORNE PARTICLES

Abstract

One of the keys of Fukushima Daiichi Nuclear Power Plant (1F) decommissioning steps is the estimation of the Airborne Release Fraction (ARF) during the removal of nuclear Fuel Debris (FD), to evaluate the potential exposure dose for workers and the public and thus contribute to define the equipment and mitigation means for FD retrieval. The URASOL and the DA projects, respectively led by JAEA and CRIEPI in collaboration with ONET/CEA/IRSN, were proposed to obtain basic data on aerosols generation and characteristics from prototypic FD-simulants containing depleted uranium oxide cut by thermal or mechanical processing tools. The whole process developed by ONET/CEA/IRSN allows the manufacturing of specific compositions and supplying corium samples for cutting (Bouyer, 2024; Denoix, 2024), the realization of cutting tests and the on-line dedicated aerosols measurements as well as sampling aerosols (Alage, 2024), to conduct initial FD simulants and aerosols post-trial analyses (Journeau, 2022; Journeau, 2023).

This paper focuses on the initial FD simulant and aerosols chemical and microstructural analyses. Results on an ex-vessel composition of FD, named VF-U3, are given.