COMPARISON OF CALCULATION RESULTS OF TRANSIENTS IN THE VVER-1000 AND VVER-1200 CORES OBTAINED USING NOSTRA CODE WITH EXPERIMENTAL DATA
29th Symposium of AER on VVER Reactor Physics and Reactor Safety (2019, Energoland, Mochovce NPP, Slovakia)
reactor dynamics and safety analysis
D. Afanasyev, A. Pinegin, S. Semenov, A. Ryzhov, NRC “Kurchatov institute”, Russian Federation
In the paper the results of comparison of experimental and calculation data for two transients in the VVER-1000 and VVER-1200 cores are considered. The calculations were performed using the code NOSTRA. The code NOSTRA is intended for simulation of processes in reactors VVER cores with defined coolant parameters at the inlet of the core.
The first of considered processes took place during switching-off one of four MCP operating on Unit 3 of Kalinin NPP in the beginning of the first fuel cycle. This process is considered in OECD benchmark. In the presented paper the data from solutions some of tasks of this benchmark are shown.
In addition to deterministic calculation of considered process the statistical analysis of the process with taking into account uncertainties of values of some process parameters and possible errors of the model of the code NOSTRA was performed. The comparison of calculation results using the code NOSTRA not only with experimental data but also with calculation results using other codes is shown.
The second considered process took place in the reactor VVER-1200 core on Unit 1 of Novovoronezh NPP-2 during the switching on of one MCP when the other three MCPs are in operation. This experiment was held at the power ascension stage to 100 %. The initial data on temperature and flow rate distribution in FA was prepared using the certified code ATHLET/BIPR-VVER.
The purpose of given research is the verification of the code NOSTRA on dynamic experiments that are concerned with changing of coolant flow rate. It is shown that the code NOSTRA describes considered processes satisfactory.