The reactor pressure vessel (RPV) has been installed at unit 1 of Akkuyu NPP in Turkey, Russian project company Akkuyu Nuclear said on 2 June. This is a key stage in the assembly of the main equipment. Prior to this, a “melt trap” was, concreting of the support and thrust trusses was carried out, and dry protection and thermal insulation of the cylindrical part of the reactor vessel were installed. Immediately before the installation of the RPV, a support ring was mounted, which carries the main weight load of the vessel.
The installation required special preparation of the on-site roads in order to transport the RPV to the power unit. After levelling the roads along the entire route, a special wheeled platform travelled from the temporary storage site to the construction site. Then, using a Liebherr LR 13000 mobile crawler crane, the RPV (weight - 330 tons, diameter - 4.5 metres , height - 12 metres) was transferred from a horizontal position to a vertical one, raised above the reactor compartment and installed in its place in the reactor shaft.
“Installation of the reactor vessel at unit 1 is one of the main events of this year,” said Akkuyu Nuclear Director Sergei Butskikh. “I would like to note the impeccable work of the assembly team and the operators of the lifting equipment. The installation required jewellery precision: the maximum permissible horizontal deviation does not exceed a tenth of a millimetre. Completing installation of the RPV will allow us to continue work on the construction of the reactor shaft.”
The progress of the installation was monitored by representatives of Turkey’s Nuclear Regulatory Agency (NDK), French engineering group Assystem (an independent organisation construction control), the experimental design bureau Gidropress (designer of the reactor plant) and AEM-Technologies (manufacturer of the RPV).
The installation was carried out using Open Top technology - through the open top of the cylindrical part of the reactor building. This optimises construction and installation operations, making it possible to begin the installation of equipment and pipelines before concreting of the floors is completed. The technology has been used successfully in construction of NPPs in China, Japan, Bulgaria and Russia, including the construction of Leningrad II with VVER-1200 reactors. Using Open Top technology, it is planned to install steam generators, pressure compensators, main circulation pumps and other main technological equipment at the Akkuyu units.
After installation of the RPV, the builders will continue concreting the reactor shaft, install supports for the components of the main circulation pipeline (MCP) and steam generators. After the installation of steam generators and casings of the main circulation pumping unit (MCPA), it will be possible to start welding the MCP, which connects the main equipment of the primary circuit.
The RPV for unit 1 was delivered to the Akkuyu NPP construction site by sea in November 2020. It was unloaded at the Vostochny sea cargo terminal, and was transported to the storage site, where it underwent an incoming control procedure, which confirmed its integrity and quality. The internals for unit 1 were shipped by Rosatom’s AEM-Technologies at the end of April. The Akkuyu NPP construction project is being implemented by Akkuyu Nuclear following an intergovernmental agreement signed between Russian and Turkey in 2010. The Akkuyu NPP, with four VVER-1200 units, is being constructed on a build-own-operate basis by Rosatom, with commissioning of the first unit planned for 2023.
