Announcing installation of the last passive water tank module for the VVER-1200 reactor under construction at China’s Xudabao NPP in Liaoning Province, China National Nuclear Corporation (CNNC) said a modular construction system at Xudabao 4 had been developed.
Since the first lift of the unit 3 reactor shaft module in 2021, the project team has adhered to the principle of “converting non-modular components to modular and using modular components wherever possible”, continuously researching and developing modular construction. This has created a modular construction at Xudabao 4, described by CNNC as a “pioneering modular construction technology both domestically and internationally, significantly improving the internal safety and quality of the project”.
CNNC added: “From reinforcement and steel cladding modules to complex prefabricated concrete structure modules, the Xudabao project team, through extensive finite element analyses and virtual optimisation simulations, controlled the accuracy of the millimetre-level lift, well beyond project requirements.” The project team “successfully researched and implemented [technologies] applicable to the VVER-1200 reactor type, gaining valuable experience for the subsequent construction of nuclear power facilities in China and setting a new benchmark for modular construction”.
As to the water tank installation, CNNC noted that the passive core reservoir of the reactor building at Xudabao 4 consists of four modules, each of which includes reinforced concrete slabs, stainless steel cladding, penetrations, heat exchangers and wall reinforcements. The lifting weight of one water tank module is 325.9 tonnes. The finished tank contains 33 penetrations with 16 heat exchangers located inside it. Its installation marks “completion of the modular construction of large components for the second phase of the Xudabao project, which lasted four years”.
The Xudabao project was originally expected to comprise six CAP1000 reactors with units 1&2 as the first phase. However, plans changed, and two Russian-supplied VVER-1200 reactors were instead designated for Xudabao 3&4 for which the contracts were signed in 2019, with construction starting in July 2021 and May 2022.
In November 2023, the Ministry of Ecology & Environment announced that the National Nuclear Safety Administration had decided to issue a construction licence for Xudabao 1&2 with 1250 MWe CAP1000 reactors – the Chinese version of the Westinghouse AP1000. Two further CAP1000 reactors are proposed for units 5&6. The Xudabao NPP is owned by Liaoning Nuclear Power Company Ltd, in which CNNC holds a 70% stake with Datang International Power Generation Company holding 20% and State Development and Investment Corporation owning 10%.
