The report deals with the work performed in the frame of the safety assessment for ITER in order to quality codes and tools used for the Non Site Specific Safety Report 2. An ex-vessel loss of coolant accident evolving in an in-vessel break for melting due to the failure of the plasma shutdown system has been studied by means of the ATHENA and INTRA codes The loop affected by the break is the FW/IBB cooling circuit The scope of the analysis is to perform a comparison with the results obtained in NSSR-2 by means of the MELCOR application, for the same accident The analysis results demonstrated a congruent behaviour of the FW/IBB cooling loop models adopted in ATHENA and in MELCOR Some discrepancies have been revealed due to the fact that ATHENA simulates only the cooling loop and the fluid contained in it, while MELCOR takes into account the radiative exchange among walls in the W too. This effect and other conservative assumptions in ATHENA modelling explain-in the faster rise of the cooling pipe wall temperatures to the set point assumed as critical for the passive plasma shutdown.
|Titolo:||Loss of Coolant Accident in the ITER FW/SB Cooling Loop. A Comparison between ATHENA/INTRA and MELCOR Analyses|
|Data di pubblicazione:||1-apr-1999|
|Appare nelle tipologie:||5.3 Documento tecnico|