Petrozavodsk Branch of JSC “AEM-technology” (a part of machine-building division of Rosatom State Corporation) entered upon manufacture of reactor coolant pipeline (RCP) for Tianwan NPS, Unit 7 (People's Republic of China). There was commenced application of anticorrosive layer by electroslag overlaying on the inner surface of the pipe blanks.
Totally 36 pipes are going to be overlaid, which will then be assembled into 16 pipe spools of RCP for Tianwan NPS, Unit 7, as well as the sets of rings intended for welding procedure qualification and welder performance qualification during installation. The reactor coolant pipeline with the inner diameter 850 mm and total length 146 m connects the major equipment of NPS primary circuit: the reactor, the steam generators and the reactor coolant pumps.
The RCP manufactured for Tianwan NPS is the first project of Petrozavodskmash related to supply of nuclear equipment to China. Apart from the items intended for Unit 7, the factory is going to manufacture the equipment for Unit 8 of Tianwan NPS, as well as for Units 3 and 4 of Xudapu NPS.
The NPS RCP is intended for primary coolant circulation at a temperature up to 330 oC under high pressure — 160 atmospheres. The anticorrosive overlay is to be applied on the inner surface of the forged blanks to protect the pipeline from the aggressive exposure to coolant. It bears reminding that Petrozavodskmash was the first in Russia to master the technique of manufacturing the seamless clad pipes for nuclear power plants.
Tianwan NPS is located in Jiangsu Province, China. The first power units 1 and 2 equipped with VVER-1000 reactors were delivered to the customer and brought into warranty period operation in 2007. Units 3 and 4 were brought into warranty period operation in 2018. An intergovernmental protocol and a framework contract for construction of Tianwan NPS, power units 7 and 8 equipped with VVER-1000 reactors which belong to the newest "3+" generation were signed that same year.