A lumped parameter modelling of particle generation from Na-pool fires in SFR containments

Abstract

Modelling of sodium-evaporation and formation of sodium-oxide aerosols from a sodium-pool fire is of fundamental

importance for the assessing of the radiological consequences in Sodium-cooled Fast Reactors severe

accidents. This paper summarizes the derivation of a simple model to estimate the amount and size of particles

being generated from Na-pool fires and its performance assessment, once implemented in an integral severe

accident tool (ASTEC-Na), against available large-scale separate effect tests. The model has been transposed in

analytical correlations which implementation in lumped-parameter severe accident codes is straightforward.

According to the comparisons to data set, the correlations do not adversely impact the code estimates with

respect to other more empirical alternative approaches and, in addition, the correlations remove any need of

user-defined ad-hoc parameters in the input deck concerning Na-based particles behaviour, as other alternates

do. Regarding code behaviour, the model predictions yield the same order of magnitude both in terms of suspended

aerosol concentration and diameter as data and capture the reliable measured data trends.