Atommash, AEM-Technologies, JSC Branch in Volgodonsk (part of the machine-building division of Rosatom - Atomenergomash) has manufactured the lower semi-vessel of the Reactor for Unit No.7 of the Tianwan NPP, which is being built in China.
This is one of the milestone stages in manufacturing a nuclear reactor. The lower semi-vessel consists of two shells and a bottom - the total weight of the structure is more than 160 tons. The welding process of these parts took place for 12 days with continuous heating of the weld zone. Next, the lower semi-vessel was heated to 300 degrees and moved to a gas furnace for heat treatment. The item was in the furnace for three days at a temperature of 650 degrees.
After the inspection of welded joints, an internal corrosion-resistant overlay was applied to the inner surface in the zones of welded joints.
The Reactor is a vertical cylindrical vessel with an elliptical bottom, inside which the Core and Internals are located. From above, the Reactor is hermetically sealed by a Cover with drives of mechanisms and control and protection devices installed on it. There are pipes for supplying and discharging the coolant in the upper part of the vessel, as well as pipes for emergency supply of the coolant in case of depressurization of the circuit.
Tianwan NPS is located in Jiangsu Province, China. The first power units No.1 and No.2 with VVER-1000 reactors were supplied to the customer and put into warranty operation in 2007. Units No. 3 and No.4 were put into warranty operation in 2018. On June 8, 2018, an intergovernmental agreement and a framework contract for the construction of power units No.7 and No.8 of the Tianwan NPS with VVER-1200 reactors, which refer to the latest generation “3+”. The design and construction of the facility is carried out by the Engineering Division of Rosatom State Corporation. The capacity of each new nuclear power unit will be 1200 MW.***