Development and validation of an agglomeration model for CFD simulations of aerosol dispersion in the frame of Fukushima fuel debris retrieval
Résumé
The general context of this article is related to demonstrate the feasibility of using laser cutting technique for the retrieval of the fuel debris of the Fukushima Daiichi damaged reactors. IRSN is involved in a project led by ONET Technologies, in collaboration with CEA, to bring relevant elements to analyse the risk occurred by the dispersion of aerosols emitted by the dismantling operations. During the laser cutting operations dedicated to retrieve the fuel debris in air condition, particles will be produced, inducing a potential risk of dispersion into the environment. Hence, evaluating the fate of these particles in terms of wall deposition and release into the environment is one of the safety key issues for these dismantling operations. In this objective, IRSN performed CFD simulations of dispersion, agglomeration and deposition of particles representative of inactive fuel debris simulants [1][2][3][4].The first numerical results [5] showed a quite good agreement with the experimental ones but also the need to use more realistic and complex particle size distributions (PSD) than the one used in these first simulations (lognormal distribution). Hence, the work presented here proposes an alternative method to better initialize the agglomeration calculation, in order to take account for different kinds of particle size distribution in the CFD simulations and to better evaluate the fate of aerosols produced by the debris cutting in the damaged reactors of Fukushima-Daiichi pedestal.