Criteria of thermochemical conditions of steam gas explosions in dynamic accident modes at nuclear power units with WWER reactors

The main lessons of the major accident at Fukushima-Daiichi NPP in 2011 for nuclear power industry identify need to model, analyze and develop emergency measures relatively unlikely events with catastrophic environmental consequences, taking into account multiple failures safety systems. Steam-gas explosions became one causes consequences Chernobyl Fukushima accidents. Criteria conditions occurrence steam-gas dynamic modes "tight" reactor circuit units (NPP) water-water reactors (WWER) systems valves steam gas removal are determined by rate change thermodynamic physico-chemical parameters. A method determining criteria a failure modeling initial – seismic effects, falling massive objects, etc. is presented. hydrogen maximum increase temperature fuel oil shells, pressure as result intensification vaporization processes. amplitude propagation speed acoustic disturbances volume. And detonation shells average flow coolant active zone reactor.