Aerosols released during the laser cutting of a Fukushima Daiichi debris simulant

Christophe Journeau (1) , Justine Zanini (1) , Emmanuel Excoffier (2) , Véronique Testud (2) , Emmanuelle Brackx (2) , Christophe Chagnot (3) , Ioanna Doyen (3) , Emmanuel Porcheron (4) , Damien Roulet (5)

1 LEAG - Laboratoire d'Etudes et d'Expérimentation pour les Accidents Graves
2 LMAC - Laboratoire Métallographie et Analyse Chimique
3 LTA - Laboratoire Technologie d'Assemblage
4 IRSN - Institut de Radioprotection et de Sûreté Nucléaire
5 ONET Technologies

One of the important challenges for the decommissioning of the damaged reactors of the Fukushima Daiichi Nuclear Power Plant is the safe retrieval of the fuel debris or corium. It is especially primordial to investigate the cutting conditions for air configuration and for underwater configuration at different water levels. Concerning the cutting techniques, the laser technique is well adapted to the cutting of expected material such as corium that has an irregular shape and heterogeneous composition. A French consortium (ONET Technologies, CEA and IRSN) is being subsidized by the Japanese government to implement R&D related to the laser cutting of Fukushima Daiichi fuel debris and related to dust collection technology. Debris simulant have been manufactured in the PLINIUS platform to represent Molten Core Concrete Interaction as estimated from Fukushima Daiichi calculations. In this simulant, uranium is replaced by hafnium and the major fission products have been replaced by their natural isotopes. During laser cutting experiments in the DELIA facility, aerosols have been collected thanks to filters and impactors. The collected aerosols have been analyzed. Both chemical analysis (dissolution + ICP MS and ICP AES) and microscopic analyses (SEM EDS) will be presented and discussed. These data provide insights on the expected dust releases during cutting and can be converted to provide radioactivity estimates. They have also been successfully compared to thermodynamic calculations with the NUCLEA database.

Keywords: Fukushima Daiichi; Aerosols; Fission Product simulants; Debris cutting

Domains: Engineering Sciences [physics]; Reactive fluid environment; Physics [physics]; Condensed Matter [cond-mat]; Materials Science [cond-mat.mtrl-sci]

Christophe Journeau, Justine Zanini, Emmanuel Excoffier, Véronique Testud, Emmanuelle Brackx, et al.. Aerosols released during the laser cutting of a Fukushima Daiichi debris simulant. The 9TH European Review Meeting on Severe Accident Research (ERMSAR2019), Mar 2019, Prague, Czech Republic. ⟨cea-02023046⟩