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) started assembly of the first vessel of the emergency core cooling system (ECCS) intended for Power Unit 1 of Akkuyu NPP constructed in Turkey.
The ECCS is one of passive safety systems of an NPP which includes 4 primary hydroaccumulators of 60 m3 volume and 60 kg pressure each, 8 secondary hydroaccumulators of 120 m3 volume and 15 kg pressure each and 12 third-stage hydroaccumulators of 60 m3 volume and 1.5 kg pressure each. All the hydroaccumulators are thick-wall vessels. During operation at a plant there is boric acid solution kept in the vessels under pressure of more than 60 atmospheres and temperature of about 50 degrees. In case the primary circuit pressure drops below some specified level, the solution is injected in the reactor instantly to cool the core.
All sets of ECCS vessels blanks have been prepared at Petrozavodskmash. The shells were manufactured from carbon steel sheets. After welding of longitudinal weld joints, the parts were subjected to intermediate tempering. A set for the first hydroaccumulator was assembled in a pipe of diameter greater than 3 meters and length greater than 7 meters.
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 for the reactor room and the turbine island equipment for all four units of the plant.