Validation of System Thermal Hydraulics Neutronics Computer Code ATMIKA LWR for KKNPP Reactors

The system thermal hydraulics neutronics computer Code “ATMIKA-LWR” is developed with the objective to perform indigenous safety analysis of VVER 1000 MWe reactors of Kudankulam Nuclear Power Plant (KKNPP) of India. The code is developed for analysis of various Postulated Initiating events (PIEs) which include Anticipated Operational Occurrences (AOO), Design Basis Accident (DBA) and Design Extension–A (DEC–A) events of VVER 1000 Reactors. The code simulates the overall thermal hydraulics of the plant along with integrated control systems viz. Primary pressure control, Steam Generator (SG) pressure and level controls, Turbine Governor controls, Reactor power control system along with Emergency protection and Preventive Protection, Safety Injection and other systems and automatic actuation logics. The various simulation studies performed and results of AOOs such as Reactor Coolant Pump (RCP) trip, Turbine trip, Reactor trip, Load rejection, Turbine Driven Feed Pump (TDFP) trips etc. are compared with KKNPP Commissioning Test results and plant events. This paper presents the validation of computer code with simulation of turbine trip test of KKNPP.