Petrozavodsk Branch of AEM-Technologies, JSC (a member of Atomenergomash, machine engineering division of Rosatom Corporation, and Karelian Regional Branch of the Russian Engineering Union) has started installing internals into half bodies of passive core flooding system (PCFS) hydroaccumulators. The items are intended for Rooppur NPP, Unit 2, which is under construction.
Eight PCFS hydroaccumulators are to be installed per one unit. Hydroaccumulators having a capacity of 120 cubic metres each are manufactured from stainless steel. The item comprises three shells and two heads. Ladders and maintenance platforms as well as other internals are installed into the body.
Three PCFS shells are assembled and joined together and to the lower head by circumferential welds at Petrozavodskmash. The resulting half bodies are fitted with the internals. The first to be installed have been the platforms, which are prefabricated welded structures made of round bar. The diameter of one platform is up to 4 meters, and the weight is more than 400 kilograms. Three such structures are placed into each hydroaccumulator.
PCFS refers to the second level of NPP passive safety systems. It is intended for removal of the coolant residual heat of the reactor primary circuit. An aqueous boric acid solution heated to a temperature of approximately 60 degrees is stored inside the hydroaccumulators during operation at the plant. When the pressure in the primary circuit falls below a certain level, the fluid is automatically fed into the reactor and the active core is cooled down.
Rooppur NPP is being designed and constructed under a Russian project. The Engineering Division of Rosatom State Corporation is responsible for design and construction of the facility. The plant will consist of two power units with VVER-type reactors which life cycle is 60 years with a possibility to extend the life cycle by another 20 years. The capacity of each unit will be 1200 MW. AEM-Technologies is manufacturing the major equipment of the reactor hall for two power units.