Fission product and structural material transport estimation during the Phebus-FPT0 transient

Phebus-FP is an international integral experimental programme initiated by the French Nuclear Protection and Safety Institute, the European Commission and 'Electricité de France'. Its objective is to investigate the main phenomena involved in LWR severe accidents through six in-pile tests. The programme is also sponsored by USA, Japan, Canada, Korea and Switzerland. The FPTO test was the first experiment carried out. Up to now, concerning this test, a large extent of experimental data has been collected and presented and best-estimate mass flow-rates (mu g/s) of fission product and structural material transported by the gas carrier in the simulated primary circuit have been even calculated. This concerns several elements, such as: Zr, Ru, Ni, Re, Te, I, Cs, Ba, Ce, Ag, Sn, In, U, Cd, Sr, and W. No data were available, however, for other elements of interest in a transport estimation, namely: Mo, Si, Cr, Fe, Ir, Mn, and Nb. This paper presents the results of a study performed to individuate possible analogy of behaviour between analysed and non-analysed elements in the specific FPTO transient conditions. By the individuation of this analogy, transport flow rates for Mo, Si, Cr, Fe, Ir, Mn, and Nb have been thus derived. As parameter of analogy among two or more elements has been. considered the trend of pressure of the volatile species with temperature and the H2/H2O ratio. Due to the assumptions made to perform this type of calculation, the treatment exposed can be believed realistically simplistic. The results, accordingly, are given solely in terms of approximate estimation.