Analysis of Accidents with CPS CR Ejection at VVER Reactor Plants with Regard to Real Hydrodynamic Forces

This work is aimed at substantiating the conservative approach used in the analysis of an accident at a VVER reactor plant (AES-2006 project) with the ejection of one cluster of absorber elements (AE) from the core. The problem of finding the law of motion of the control and protection system control rod (CPS CR) is solved with its postulated ejection in an accident with a rupture of the drive housing. For this purpose, a mathematical model of CPS CR is used that takes into account the geometric characteristics of AE and the hydrodynamic situation in the core in the event of a leak. An analysis is made of the influence of the law of motion of one CPS CR cluster on the disturbances introduced into the reactor at different initial states of the reactor plant.