The Volgodonsk branch of “AEM-technology” “Atommash” (a part of the machine-building division of Rosatom - Atomenergomash) has manufactured a set of bends for the main circulating pipeline (MCP) for Unit No.7 of Tianwan NPS.
Works on manufacturing of MCP bends are carried out in three stages. First, an oval shape is given to the blanks using a press. The second stage is stamping. The parts are being heated up for about two hours at 870 degrees, and then for about an hour at 1080 degrees. Then the press, with a force of 6300 tons, applies pressure on the blank and forms items with an angle of 90 degrees. At the third stage, it is necessary to perform quenching of the completed bends. To do this, hot sharply-curved bends are taken out of the furnace, with the help of a crane they are transported to a quenching tank with water. Operation time shall not exceed 10 minutes. In total, 12 MCP bends will be manufactured. Weight of one bend is 7 tons, outer diameter is 995 mm.
After stamping, the specialists of the plant will carry out visual and dimensional inspection, destructive and non-destructive tests and machining.
The main circulating pipelines (MCP) are designed to connect the main equipment of the primary circuit of NPS: a reactor, steam generators and main circulating pumps. A coolant circulates through them - water with a temperature of 320°C and a pressure of up to 17.6 MPa. The pipelines belong to the first seismic category and are able to withstand the earthquake of magnitude 9. The total length of the pipeline is over 160 meters.
Tianwan NPS is located in Jiangsu Province, People’s Republic of China. The first power units No.1 and No.2 with VVER-1000 reactors were handed over to the customer and put into warranty operation in 2007. Units No.3 and No.4 were introduced into warranty operation in 2018. On June 8, 2018, an intergovernmental protocol and a framework contract for construction of power units No.7 and No.8 of Tianwan NPS with VVER-1200 reactors, which belong to the newest generation "3+", were signed in Beijing. The design and construction of the object are carried out by the Engineering Division of the State Corporation “Rosatom”.