The Petrozavodsk branch of AEM-technology (a part of machine-building division of Rosatom State Atomic Energy Corporation - Atomenergomash) has completed manufacturing of valves for Units 3 & 4 of the Kudankulam Nuclear Power Plant in Tamil Nadu, India.
Six swing check valves and twelve wedge gate valves with 80 to 400 mm throat diameter are intended for the turbine island and will be operated under pressure of up to 12 MPa and temperature of up to 350 ºC.
Valves are designed to stop, allow or throttle the flow of a process fluid. The main steam isolation valve is installed at the outlet part of the steam generator and is used to shut off the steam to prevent its release into the atmosphere at the time of an unforeseen accident such as breakage of the main steam pipe. VVER-1000 is a thermal neutron reactor with pressurized water used both as coolant and moderator. Its design features include a two-circuit steam generating system with four cooling loops, main circulation pump, pressurizer, relief and emergency valves on steam pipes, and accumulator tanks of the emergency core cooling system (ECCS).
The emergency core cooling system features advanced technologies, and one of them is cold boric acid stored under pressure in special tanks. In case of containment or pipeline rupture, valves open and boric acid is injected into the reactor core to stop the chain reaction and cool down the reactor.
The valves have passed the whole scope of factory tests including hydrostatic tests for strength and tightness of assembled item when it is held under pressure of 16.5 MPa for 10 minutes. Indian side carried out an acceptance inspection of the equipment. The supply package is ready for dispatch.
Pipeline valves are a serial product of Petrozavodskmash. It is manufactured at a specialized site according to design documentation developed by the company. The blocking element of a gate valve has a shape of a wedge and moves straight across the flow of the operating medium by actuator action; in a check valve the blocking element moves by flow when it is turning back. The valves are used in both low-pressure and high-pressure nuclear power plant pipelines.