Petrozavodsk Branch of JSC “AEM-Technology” (a part of machine-building division of Rosatom State Corporation – Atomenergomash, and a member of Karelian Regional Wing of the Russian Engineering Union) has manufactured cylindrical parts – shells – for assembly of passive core flooding system (PCFS) tanks for Unit 1 of Akkuyu NPP (Turkey).
Every PCFS tank consists of three shells and two dished ends. The shells are made of 60 mm thick stainless steel rolled plates. In order to make one part, a 2.5 m wide and 13 m long blank is formed on a bending machine into a cylinder with inner diameter of 4.1 m. Petrozavodskmash manufactured all 24 shells for a set of PCFS tanks for Akkuyu NPP. After machining the shells will be used to assembly PCFS vessels.
PCFS belongs to the second stage of NPP passive safety systems; it is designed to remove the residual heat of the primary circuit coolant. The system comprises eight hydroaccumulators with capacity of 120 cubic meters. During operation at NPP boric acid water solution, heated up to the temperature of about 60 degrees, is stored in the tanks. In case the primary circuit pressure falls below some specified value, the fluid is supplied automatically into the reactor and the core cooling takes place.
Akkuyu NPP in Turkey is constructed according to an improved NPP design with GenIII+ VVER-1200 power units with enhanced safety and improved technical and economic features. JSC "Atomenergomash" is the single-source manufacturer of equipment for the reactor system and the turbine island for all four units of the plant.