The Volgodonsk branch of Russia’s AEM-technology Atommash (part of Rosatom’s mechanical engineering division Atomenergomash) said on 6 August that it had manufactured a set of elbows for the main circulation pipeline (MCP) for units 7 and 8 of China’s Tianwan NPP and units 3 and 4 of the Xudabao NPP. The work was carried out in two stages at the thermal press section of Atommash. At first, the specialists performed ovalisation – the blanks with the help of a press were given the necessary oval shape. At the second stage, the bending of the products took place. After two-stage holding in an oven at a temperature of 870 to 1080 degrees, the elbows were placed in a specialised stamp. Under pressure from a press with a force of 6,000 ton-forces, the workpieces were bent at 29 degrees. The mass of the finished product is 2 tons, the diameter is 1050mm. In total, specialists manufactured 16 MCP components for the two NPPs in China.

After stamping, the plant's specialists carry out visual measurement control, destructive and non-destructive control methods and machining. MCP elbows are the constituent elements of the main circulation pipeline that connects the main equipment of the NPP primary circuit: a reactor, steam generators and main circulation pumps. A coolant circulates through them – water with a temperature of 320°C and a pressure of up to 17.6 MPa. The pipelines are able to withstand a magnitude nine earthquake. The total length of the pipeline is over 160 metres.

In June 2018, Russia and China signed four agreements for the construction of two VVER-1200 reactors as units 7&8 at the Tianwan NPP in Jiangsu province and two more to be built as units 3&4 at the new Xudabao NPP site in Huludao, Liaoning province. Further agreements signed in June 2019 included a general contract for the construction Xudabao 3&4, as well as a contract for the supply of nuclear fuel. Rosatom will design the nuclear island and supply key equipment, as well as provide installation supervision and commissioning services for the equipment. Turbine generators for the plants will be supplied by China. The power units are expected to be commissioned in 2027-2028.

Photo: MCP elbows (photo credit: Rosatom)