28th Symposium of AER on VVER Reactor Physics and Reactor Safety (2018, Olomouc, Czechia)
Reactor dynamics and safety analysis
M.V. Suslov, I.G. Petkevich, M.A. Uvakin (Gidropress)
The paper deals with the results of the Leningrad NPP-2 start-up loss of power test and its simulation with use of KORSAR/GP code. The test was held at the 1st unit with VVER 1200 reactor on the 29th of March.
During the test the steam generators were refilled with EFW system at first. This system is connected to the SG steam space. Therefore injection of water leads to the secondary pressure decrease. This phenomenon is difficult for simulation due to complicated structure of the SG internals.
Also the test provides unique data for the reactor facility cooldown at natural circulation in the primary circuit. The important data for reactor head and pressurizer cooldown were obtained.
Thus the test data provides the validation of several processes such as:
- emergency feedwater injection into the steam generator;
- steam generator filling with “cold” water from AFWS;
- pressure regulation at filled pressurizer;
- cooldown of the reactor head and the coolant circulation beneath the head.
The results of the test were used for the validation of KORSAR/GP code, unit nodalization and equipment models.