The bridge of the polar crane for unit 1 of the Sanmen nuclear power plant in China's Zhejiang province has been raised into position near the top of the reactor building. Once the lifting mechanism has been installed on this, the dome of the reactor building can be put in place.
The bridge of Sanmen 1's polar crane during the lift (Image: SNPTC)
The 350-tonne bridge was successfully raised into place on 15 January, State Nuclear Power Technology Corporation (SNPTC) reported. Sitting on a circular rail, it can rotate 360 degrees and will be used to lift reactor components and main pump components.
A trolley and lifting mechanism will now been installed on the bridge to complete the crane, after which the dome of the reactor building can be built on top of the containment walls, marking another milestone.
Polar cranes are used in pressurized water reactors to lift reactor vessel heads, internals, and a multitude of lighter loads during refuelling outages. In some plants the polar crane is also used to lift the reactor vessel itself and the steam generators during construction. The AP1000 crane has a main hoist capacity of 300 tonnes and an auxiliary hoist rated at 25 tonnes. The bridge has a rated capacity of 800 tonnes to enable it to support special construction lifting equipment if necessary. The AP1000 polar crane is almost 38 metres long, 13.5 metres wide, and weighs more than 450 tonnes. This model was manufactured at the NuCrane facility in Hutchinson, Minnesota, USA and was transported in sections.
Sanmen 1 is one of two AP1000 units being constructed at the site and is the lead unit of four AP1000s currently being built in China, the other two being at Haiyang. All these are scheduled to begin operating between November this year and March 2015.
Researched and written
by World Nuclear News