UK Nuclear Licensed Site – Semi-Automated Raft Cranes

A UK nuclear-licensed site had a pair of existing Goliath cranes that were beginning to fall short of the site’s increasingly demanding requirements. A wide range of factors needed addressing including operator safety, facility capacity, and future-proofing. To meet the challenge, SCX engineered one of the most advanced cranes it has ever produced. It called on every engineering discipline from mechanical, to electrical, to hydraulic, to controls and safety.

The Challenge

Our client has a facility handling nuclear processing materials at its site in north-west England. The waste is packaged into cement and steel cylinders and stored on two 330-metre long ‘rafts’.

The previous raft cranes were operated from the raft itself. This placed operators in controlled areas with an increased risk of exposure, and manual visual positioning meant that cylinders could only be stacked two high.

The Solution

Our solution was two semi-automated and remotely controlled ‘Goliath’ raft cranes, significantly reducing operator exposure and facilitating triple-stacking of cylinders to make better use of the storage facility.

SCX designed, built, tested and installed two cranes, each with a sophisticated rotating and latching grapple, to run on the existing raft rails. The solution has bespoke nuclear protection features including our MotoSuiveur load arrest devices, CCTV and load recovery.

Technical Details

Extensive acceptance testing at our Sheffield facility

A blend of proven MOTS (modified off the shelf) lifting equipment with bespoke mechanical, electrical and control design
Design working life of 30 years, supported by calculations, documentation and comprehensive acceptance testing
Replica raft and rails constructed at our Sheffield assembly site to match the client’s site specifications

Semi-automated control for operator safety

A quad-scrolled hoist, customised to give a 16-rope fall for true vertical lift and pinpoint positioning
Semi-automated control, allowing operators to be sited well away from radioactive assets
A laser and radar tracking system that knows where any asset is on the raft
Data and 13 CCTV cameras feed back to control room SCADA workstations

Advanced crane and hoist design

330-metre long-travel, 35-metre span between the rails, and 30-metre cross-travel to allow the crane access to all areas of the raft
25-tonne safe working load, significantly de-rated for safety, with a lift height of 5.0 metres
VSD-controlled motors for long travel and lifting

MotoSuiveur load arrest device

Exclusive to SCX in the UK, and in use at many UK Nuclear-Licenced Sites
Independent of other electrical and mechanical systems, plus a damping effect to reduce shock loading
Even with complete mechanical failure of the hoist gearbox, the load would fall a maximum of just 30mm

Safety and integrity through expert EC&I design

Extensive data logging including load position in all dimensions and rotations, load weights, plus wind speed and temperature
High-speed cross and long travel are only allowed when the grab and its load are interlocked to the crab
Laser, radar and absolute encoder systems for X-Y-Z positioning

Precise payload handling, indexing and positioning

Cylinders are moved between indexed raft locations, facilitating regular movement of packages until ready for re-processing
3-D cylinder location map, delivering a triple-stacking capability to increase storage capacity by nearly 50%
Hoist lift speed of 5.0/0.25 m/min, cross travel of 50/5 m/min, and long travel of 90/5 m/min, slew speed of 0.5 rpm, all VSD-controlled

From initial designs, to build, to commissioning and beyond

SCX is uniquely positioned to design and build nuclear lifting projects, as well as deliver ongoing maintenance
Decades of experience working with Tier 1 and Tier 2 providers
A deep understanding of meeting nuclear functional safety requirements

Nuclear safety is a priority

Seismically tested, with mechanical anti-uplift devices added to end carriages and crab units
Multiple braking solutions including primary VSD, secondary MotoSuiveur load arrest devices and storm anchors
Full traceability and documentation to required standards for UK Nuclear Licensed Sites

Innovative design considerations

Each cylinder is bar-coded, read by a camera mounted on an articulated retractable arm
Detachable inspection mast for maintenance and observation
Electro-mechanical grab removes the need for hydraulic power supplies, plus associated spillage and fire risks

Explore more specialist handling solutions from SCX

UK Nuclear Licensed Site – Semi-Automated Raft Cranes

The Challenge

The Solution

Technical Details

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