Rosatom’s Engineering Division (ASE) said on 2 December the serial use of two types of automatic orbital welding machines has been launched at the Rooppur nuclear power plant under construction in Bangladesh.
Use of the new automatic welding machines had been agreed with the design organisation and supervisory authorities as a result of joint work by Energospecmontazh JSC and the Centre for Technology Transfer and Technical Policy of ASE.
Three automatic argon-arc welding apparatuses (AADs) and an argon-arc welding apparatus based on the auto-pressing method are now in operation at the site. Previously such devices were tested during the construction of Novovoronezh-II in Russia and the Belarus nuclear power plant.
AADs are 15% faster than manual welding. Their main advantage is ensuring a consistently high quality of seams. The use of devices at Novovoronezh showed that there is no need to redo work, while a person sometimes admits a defect and has to spend time fixing it. These devices have been used at the Rooppur since September, but the main load will fall on them in 2022.
Bengali personnel were trained to work at the AADs. Students first completed a 16-hour theory course, followed by a two-week practical course. The AADs purchased by Energospecmontazh operate using argon-arc welding technology with automatic wire feed. The operator only needs to adjust the device to the parameters of the pipeline.
Another new automatic device is based on TIG welding technology by the method of auto-pressing (flashing). This makes it possible to weld a joint 40% faster than a professional welder. In this case, it is not required to prepare pipe joints. The only limitation of this technology is the diameter and wall thickness of the pipe being welded. Therefore, the auto-pressing welding machine at the Rooppur NPP is used in parallel with AADs.
“It is important for us that welding using AADs and auto-pressing can be performed not by welders, but by operators who can be trained in two weeks,” said Denis Kalinin, head of the production system development at Energospecmontazh. “Often there are enough installers at our construction sites, and qualified welders are always in short supply. A big plus of automatic devices is that we can ensure high quality and speed of welding, freeing welders to perform more complex installation work.”
Polar crane installed at Rooppur 2
Meanwhile, work is proceeding at the Rooppur NPP. A polar crane bridge was installed at Rooppur 2 on 29 November.
Energospecmontazh specialists lifted and installed the beams of the polar crane bridge at the elevation of +38.50 metres on the rail tracks using a Liebherr heavy crawler crane with a lifting capacity of 1350 tons.
“The installation of a polar crane is one of the most important events in the construction of a power unit, said Aleksey Deriy, ASE Vice President and Director of the Rooppur NPP Construction Project. “After the adjustment and testing of the crane, installation of the main heavy equipment and pipelines in the reactor compartment will begin.”
Currently, work is underway to install structures and crane mechanisms on the crane runways. After the NPP is put into operation, the crane will be used for repair work and fuel transportation.
The Rooppur plant is being built by Rosatom on the eastern bank of the Ganges River in Bangladesh’s Pabna district about 160 km northwest of the capital city of Dhaka. It will comprise two VVER-1200 reactors: Rooppur 1 is scheduled to start operating 2023, followed by Rooppur 2 in 2024.
Automatic argon-arc welding sets are being used at Rooppur (Photo credit: Rosatom)