Through its exclusive UK dealer Cooper SH, Konecranes has supplied a special reach stacker to handle 45t concrete overpacks containing intermediate level nuclear waste (ILW) for Magnox North at its Trawsfynydd site in Wales. The machine will move the ILW into a purpose built store that will contain the waste until a national repository has become available.

Konecranes has designed a special attachment to handle the specially built 2,5 m2 overpacks that encase a heavy duty stainless steel box in which the waste is transported. Critical factors to the safe application include the control of the vertical lift, the distance of the driver from the box of ILW and a number of bespoke recovery procedures.

Doug Barber, ILW Store Project Lead at Trawsfynydd, commented: "This is an unusual handling application in that the number of lifts is small, but the operation needs to meet the highest levels of environmental, security and safety standards.

"The UK nuclear industry is one of the toughest industrial regimes in the world. And we needed absolute control of the vertical lift, a machine that could perform accurately under extremely slow conditions as well as a facility for total manual override."

Magnox North personnel were involved throughout the design, manufacturing and testing process that saw numerous visits to the Konecranes production facility in Markaryd, Sweden. This was an essential pre-requisite of the supply contract to adhere to the strict quality demands of the nuclear industry.

The specially designed attachment has elongated twist locks that produce a synchronised arc and extension as the boom moves in, ensuring a permanent vertical lift. The machine has also been programmed with different logic and load curve characteristics to handle the waste load versus the lighter stillage utilised for handling drums, thereby ensuring each load is handled with the same care and attention.

"This is the first time we have been asked how slow our reach stacker could lift and lower, or how much air spare there is between the driver and the load", said David Cooper, managing director of Cooper SH, Konecranes distributor in the UK. Both parameters were critical in safe operation at Magnox. In addition, we were asked to provide an override system to raise the boom manually in the eventuality of truck power failure.

"A second electronic override system was also specified to ensure the machine could only travel empty when the boom was at a pre-determined height to eliminate accidental damage to the extended twistlocks."