Effects of the start-up characteristics of hydrogen recombiners on the formation of explosive environment in the containment: a calculation study for the AES-2006 project

The present article assesses the effect of the time nessesary for a hydrogen recombiner to reach its nominal capacity on the formation of explosive concentration for a hydrogen-containing environment in the containment rooms under the conditions of a severe accident at a VVER nuclear power plant. We calculate thermodynamic parameters of the environment in the containment rooms for various times of achieving the nominal capacity of the recombiner. The calculations are performed in the KUPOL‑M integral code. The LIMITS‑V code is used to analyse possible combustion modes of the hydrogen-containing mixture formed during the development of the considered severe accident. An increase in the time for reaching the nominal capacity of the hydrogen recombiner leads to the growth of hydrogen concentration in the containment rooms and emergence of conditions for the detonation of the hydrogen-containing mixture.