Severe Accident Analysis of a PWR during LBLOCA without ECCS using RELAP5/SCDAP and CONTAIN Computer Codes

RELAP5/SCDAP and CONTAIN are two widely used severe accident computer codes for the integral analysis of the core and containment behaviour following the core degradation. Because the containment is an important factor in mitigating the consequences of a severe accident, it is necessary to assess its integrity after the accident has taken. The objective of the paper is the evaluation of thermal hydraulic behaviour of the PWR plant on core damage progression. The analyzed transient was Large Break Loss-of-Coolant (LBLOCA) without actuation of safety injection system (SIS). The RELAP5/SCDAP output used as input to CONTAIN to assess the containment conditions at vessel breach. The RELAP5/SCDAP predictions of the temperature and mass flow rates of water, steam, and hydrogen from the RCS and RPV failure time used as inputs to the CONTAIN calculations.