CV bottom head successfully hoisted at Unit 2 of CGN Lufeng Nuclear Power Project

At 16:36 on Feb. 6, 2026, the steel containment vessel (CV) bottom head for Unit 2 of the CGN Lufeng Nuclear Power Project was precisely positioned at the center of the reactor building's raft foundation. This followed a series of high-precision maneuvers, including lifting, rotating, traveling with load, and fine-tuning. As the first large nuclear-grade module hoisted for Unit 2, its placement marks a critical phase in the civil engineering work of the reactor building.

The steel containment vessel serves as a vital barrier for the nuclear island and is assembled from six components: the bottom head, four ring sections, and the top head. The hoisted CV bottom head features a hemispherical structure with a maximum inner diameter of approximately 39.6 meters, a height of 11.4 meters, and a total hoisting weight of about 843 tons.

For this operation, a joint engineering management team was formed by Lufeng Nuclear Power, Hepeng Supervision, the Shanghai Nuclear Engineering Research and Design Institute (SNERDI), and other participating units. The team addressed on-site technical and coordination challenges, assessed difficulties faced by construction crews, and resolved practical issues to ensure smooth transitions and rapid responses across all operational stages.

Prior to the hoisting, the project team established a comprehensive technical support system. They utilized finite element analysis for stress simulation, 3D modeling for center-of-gravity calculations, and 3D laser scanning to identify and resolve interferences. The bottom head and its support structures were precisely measured and marked, followed by an on-site dry run. A real-time stress monitoring system and multi-point balanced control technology enabled precise management throughout the lifting, horizontal movement, and final positioning, ensuring quality and safety. The integration of technical simulations with an on-site guidance and positioning system provided a robust framework for high-precision placement.

During assembly, the project team successfully applied automated gas metal arc welding (GMAW) to the CV bottom head for the first time, significantly improving welding efficiency and quality, setting an industry benchmark. This technology ensures highly consistent process parameters through innovations such as integrated welding equipment, a strong-magnetic flexible track system, and an intelligent oscillation mode. Additionally, the team optimized the construction logic, decoupling the constraints between inter-layer steel plate welding and hoisting. These advancements substantially accelerated the assembly process, enhancing both quality and efficiency for the project.