Pressure waves in the primary circuit of the VVER-1000 reactor at instant stop of the MCP

Abstract

The initial stage of the accident caused by the instantaneous stop of the main circulation pump (MCP) of the first loop of the VVER-1000 reactor plant (RP) is considered. The appearance of pressure waves and their propagation in the equipment of the primary circuit of the RP is shown. For the calculation, the parameters of the typical RP V-320 (VVER-1000), in particular, the 3rd unit of the Kalinin NPP, are used. All initial data for the calculation is obtained from the international standard problem Kalinin-3 [1-2]. Calculations were carried out using the computational best estimated code ATHLET [3], developed the society for reactor safety (Gesellschaft fbr Anlagen-und Reaktorsicherheit-GRS), Germany and certified in Russia for use in calculations to justify the safety of reactors with water coolant [4]. In case of an accident, the failure of the load-off and reactor power controller (LRPC), automatic reactor power controller (APC), warning protection systems is assumed. Emergency protection reactor (PR-1) only works on the 2nd signal. The considered emergency situation is included in the list of mandatory reports for different types in the justification of VVER safety [5]. The obtained results can be used as boundary conditions for the analysis of equipment strength in this transition process.