ANALYSIS OF FISSION PRODUCTS AND OTHER MATERIALS RELEASE DURING THE PHEBUS TEST TRANSIENT WITH THE ASTEC V1.3REV2 CODE

The previous investigation [1] showed some critical errors of the ASTEC code coupled calculations for the aerosols behavior during the PHEBUS FTP1 test transient [2,3], while ASTEC CPA stand-alone calculation results have a rather good agreement with the experimental data. Looking for the reasons of wrong prediction of aerosols behavior in the containment was made. The research of fission products and other materials flow rates and the evolution of the inventory composition that is reaching the containment had been performed by ASTEC V1.3rev2 code [4]. The prediction of the aerosol behavior shows the following errors: - Time shift (it's clear that the aerosol arrives too earlier); - The curve shape (non pronounced or absentee peak, in fact); - Amount differences. The following objectives are considered: - Cumulative and elemental distributions of mass flow rates of elements reaching the containment during the PHEBUS FPT1 test transient; - Silver problem; - Evolution composition of elements reaching the containment during the PHEBUS FPT1 test transient; - Cumulative and elemental masses of elements reaching the containment during the PHEBUS FPT1 test transient; - Deposits in experimental lines after the test transient.