Benchmark calculation on reactivity compensation initiated by dilution of boron acid in VVER-1000 primary circuit coolant by stepwise control rods group insertion

28th Symposium of AER on VVER Reactor Physics and Reactor Safety (2018, Olomouc, Czechia)
[2] Reactor physics experiments and code validation (benchmarks)

Authors

O.Yu. Kavun, V.V. Semishin, V.O. Kavun, G.R. Pipchenko (SEC NRS)

Abstract

This work represents benchmark calculation which is designed to provide the framework to assess the ability of the traditional multi-physics codes to predict the transient response of the NPP. This benchmark is based on the measurements results obtained while power increasing during Rostov NPP unit 2 commissioning.

During the experiment, the make-up system is switched to a pure condensate mode. The above action leads to a decrease of boron acid concentration in the primary circuit coolant and to subsequent increase of the core power. To keep the power constant the control rods group number 10 is inserted with the small step increment.

Calculation of fuel burnup up to the date of the experiment was made with neutron-physical module Desna of Rainbow-TPP code according to the average daily load schedule provided in the input data. The modeling of the experiment was carried out using the full-scale model of VVER-1000 based on Rainbow-NPP code complex. Two-group neutron-physical cross-section library has been calculated by Sapphire-95 code. Obtained results were compared with the results presented in the benchmark specification.