The verification results of Methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER‐1000 reactor plants
26th Symposium of AER on VVER Reactor Physics and Reactor Safety (2016, Helsinki, Finland)
Core surveillance and monitoring continues
Abstract
THE VERIFICATION RESULTS OF METHODOLOGY FOR DETERMINING THE WEIGHTED MEAN COOLANT TEMPERATURE IN THE PRIMARY CIRCUIT HOT LEGS OF WWER-1000 REACTOR PLANTSIu. Saunin, A. Dobrotvorski, A. Semenikhin, A. Korolev, S. Ryasny JSC “ATOMTECHENERGO”, Mytishchi, RussiaABSTRACTThe new methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants has been developed by experts of JSC “Atomtechenergo”. It was represented at 25th Symposium АER on WWER reactor physics and safety research. The new methodology development was defined by necessity to decrease error in calculation of the weighted mean coolant temperature in hot legs due to the coolant temperature stratification. The executed experimental and calculating researches results have been considered in the developed methodology.Methodology verification has been fulfilled by comparison of calculations results received with using and without using methodology in various operational conditions of three WWER-1000 power units. These power units have differences in structure and placing of temperature detectors and also differed in fuel loading. For the aims of verification 39 operational conditions have been analysed. They were differed in reactor power levels, positions of control rod regulating group and etc.The received results of verification have confirmed that with using of new methodology the objective decreasing of error in determining the weighted mean coolant temperature in the primary circuit hot legs is reached. The amount of decreasing depends on the character of stratification which is various for different objects. The maximum decreasing of error among investigated objects during verification was 0,6 °С.The executed verification shows that it is necessary to continue researches of coolant temperature stratification in hot legs and possibilities of new methodology for determining the weighted mean coolant temperature in the primary circuit hot legs of WWER-1000 reactor plants.26th Symposium of AER on VVER Reactor Physics and Reactor Safety 32 10 – 14 October 2016, Helsinki, Finland