4,000-tonne Zoomlion crawler sets nuclear dome at Changjiang

The lift

The dome was raised at the Phase II construction site of the Hainan Changjiang nuclear power plant and set on the reactor building cylinder. Zoomlion reports final positioning accurate to within millimetres after roughly two hours of work.

The ZCC89000 is the company’s flagship 4,000-tonne class crawler, developed for nuclear power, petrochemical and comparable heavy industrial work. It is designed to work with a superlift counterweight arrangement and carries an intelligent co-ordinated control system. The dome itself was an integrally welded module — large in both mass and volume, and with tight tolerances at the point of connection.

Dome placement is one of the set-piece milestones of a nuclear build. The module is lifted complete, there is no practical way to adjust it once it is landed, and the surrounding structure leaves very little clearance, so the crane has to be able to hold a large load steady at height for an extended period rather than simply pick it.

Controlling the deviation

The main technical difficulty was not the weight but the tendency of a component of that size to drift during the lift, and the accuracy demanded when landing it. The project’s engineering team developed a purpose-built guiding and limiting device for the operation.

During the lift the crane worked against that device, using fine circumferential angle adjustment and positional guidance to hold deviation of the steel liner within millimetres and secure a clean fit between the outer shell and the liner.

Rehearsed in three dimensions

The whole sequence was modelled before it was executed. A full-size digital model of the outer dome was built and used to simulate the lift path and the critical connection points, with collision detection run against the surrounding structure. Zoomlion says the crane reproduced the simulated path in the actual operation, which was completed in a single attempt.

That approach — digital rehearsal followed by a one-shot lift — has become standard practice on nuclear dome placements, where a second attempt is costly and the tolerances leave little room for on-the-day improvisation. The manufacturer says it will continue to supply intelligent and digitally equipped heavy machines to major projects in the clean energy sector.

Source: Zoomlion — Photos: Zoomlion