Investigation of Hydrogen Behaviour in the Test Facility THAI by Simulation of Severe Accident Conditions in the Containment – V. Krusteva, P. Groudev

This paper presents a discussion of the results received in a simulation of hydrogen deflagration and flame propagation during experiment HD-22 in the test facility THAI. The analysis has been performed by the integral computer code ASTEC.

The assessment of severe accidents indicates that a significant load on the containment may occur, reaching or even exceeding the design loads due to hydrogen combustion. Therefore, loads such as melt jets, direct heating of the containment structure, deflagration or detonation of hydrogen are likely to cause significant risks to the integrity of the containment. The mode of destruction of the containment is the decisive factor for external effects. One of the factors that can occur at each stage of a severe accident and threatens the final barrier against non-proliferation of radioactivity is the generation, spread and burning of hydrogen. Therefore, it is very important to properly simulate the processes in the containment. For this purpose, modules for processing hydrogen behavior in the containment have been developed. These modules are introduced into the integral code ASTEC.

Keywords: THAI (Thermal- hydraulics, Hydrogen, Aerosols, and Iodine) facility, ASTEC (Accident Source Term Evaluation Code), HD (Hydrogen- Deflagration), CPA (Containment Part of ASTEC).