Modeling of ultra-fast accident cooling of the wall of the reactor vessel WWER-1000

Zaporizhzhia Nuclear Power Plant (NPP) is under temporary occupation. There are reasonable suspicions regarding compliance with all the norms and standards of Ukraine and the IAEA recommendations. Deliberate sabotage measures are possible, the result of which will lead to an emergency cooling mode of the WWER-1000 reactor vessel. The reactor vessel resource determines the service life of the entire NPP unit. The complex and dangerous situation that has developed at the Zaporizhzhya NPP, due to possible emergency modes with ultra-rapid cooling of the reactors, may lead to their failure, and therefore to the failure of the Zaporizhzhya NPP units. The emergency mode of ultrafast cooling of the reactor at a speed of 1800 degrees per hour is considered with a numerical solution of the problem of unsteady heat conductivity. The effect of this mode on the cyclic damage of the metal of the reactor vessel and on its brittle strength was evaluated. An appropriate prognosis of its radiation lifetime was made. For this, the worst postulated critical crack, for which the predicted lifetime of the reactor is the smallest, is determined. The express methodology of the specified calculation assessment for the reactor vessels was tested, which contains all the necessary sections according to the norms and recommendations of the IAEA: thermal conductivity, stress state, cyclic damage, radiation lifetime. The methodology is relevant and useful for assessing the safety of reactors of the WWER type and negative consequences, including in the conditions of terrorist actions of the occupation administration