Computer Simulation of Measurements of VVER-1200 Emergency Protection Efficacy

The ratio of the reactivity calculated from the solution of a conditionally critical problem for the neutron flux density and the reactivity obtained using the measured values of the ionization-chamber currents. The efficacy of the emergency protection was measured at reactor startup of the Nos. 6 and 7 power units of the Novovoronezh NPP and No 5 unit of the Leningrad NPP. The ionization chambers are situated in the biological-protection concrete. The measured and calculated values of the efficiency of the emergency protection are compared using the results of design modeling based on calculations of the ionization-chamber currents. The measured values of the quantities are compared with the calculated values.