UNIQUE DOUNREAY POLAR CRANE REFURBISHED

17th May 2007

Holding centre stage within the historic Dounreay sphere is the unique Goliath crane, one of the first polar cranes in the world. Installed fifty years ago in the Dounreay Fast Reactor (DFR), the original crane was in need of renovation in order to bring it up to the modern standards required to decommission and dismantle the reactor and ancillary plant inside the dome.

Due to the age of the equipment, the curvature of the sphere and the limited access routes, the project presented the DFR project team with many unique challenges. The crane has been safely and successfully upgraded by installing a new crab, replacing the existing two carbon steel crabs, a rewire of the electrical system, anti-collision system and the polar travel drive system.

The £2m refurbishment also needed to increase the reach of the crane to permit the hook to operate at a greater radius and so access more areas of the facility. The overall lifting capacity of the crane and the hook operating envelope were maintained at their original values. A new maintenance access platform was added to the structure to assist in future crab maintenance.

With an exemplary safety record, the extensive crane refurbishment project has contributed to DFR's excellent achievement of over four years without a lost time accident, which given the nature of the work that is being carried out in the plant is a commendable record. Both the NII and the HSE made spot visits to the project in their campaign for working safely at height and were very happy at the work being undertaken. Well deserved praise was given to local contractors Caithness Scaffolding for the unusual scaffolding design required for erecting the assemblies within the
spherical building and confined spaces.

With safety always at the forefront, working with the primary contractor Weir, Strachan & Henshaw, UKAEA has implemented many distinctive design techniques on behalf of the NDA. In order to ensure continued safe operation and maintain full visibility within the spherical building, the main operating control station is housed within the control cab, with a portable pendant control box and umbilical cable to permit the operator to have fine control of the crane motion at the reactor floor level when
required.

Mike Brown, DFR decommissioning manager, said: "The decommissioning of the DFR facility is critical to Dounreay's programme delivery. The refurbished crane will play an integral part in stripping out the reactor and will be used primarily for removing the breeder elements in custom made flasks. UKAEA, and its contractors, have worked tirelessly to overcome the challenges associated with this project and have demonstrated forward thinking and commitment to one of the major decommissioning milestones in the clean-up programme for DFR, whilst maintaining an exemplary safety record in the process."

Complete decommissioning of the famous dome is expected to take until 2030 to complete, at a cost in the region of £250 million.