Nuclear Travelling Crane Overhaul - Magnox Harwell Vault Store

Aerospace, Nuclear & Defence

The challenge

A 5-tonne SWL overhead travelling crane at Magnox Harwell had reached the end of its design life. The vault store that it serviced however, would be active for many decades and a fit-for-purpose lifting solution was vital.

Modern safety requirements, a desire to retain as much of the solid underlying infrastructure, and an extremely tight working area added to the challenge. Overhauling the crane was preferable to the expense of an entirely new system, but was it a viable option?

The solution

After undertaking a full assessment of the site, SCX Special Projects delivered a full electrical and mechanical upgrade of the crane and ancillary systems. The complete solution includes a new retrieval system, cable management arrangement, additional interlocks, and upgraded grapple.

The panels and electrics were also overhauled to resist the radioactive environment that they operate within. Redundancy was also added to numerous other components including cable cutters, CCTV signal path, and clutch assemblies to remove potential points of failure.

An extensive upgrade

  • The crane and grapple are rated with a revised SWL of 2 tonnes, with a 7.5m height of lift, and variable speed control
  • The grapple was completely overhauled with new primary and secondary drives, mechanical clutches, and contamination resistant lifting feet and landing blocks
  • The crane is operated remotely from the building’s control room, while limited functions are available from the maintenance panel located in the building’s new local test facilities


Always recoverable

  • The new retrieval system can return the crane to the maintenence area from any location within the vault
  • This comprises of a new winch, deflector pulley assemblies, an additional rope path, and new dolly and associated track running parallel to the existing one
  • This is capable of recovering the crane from extreme failure conditions, such as all four wheels having seized, or end carriage axle failures


Safe travel

  • The new monospiral long-travel and grapple cable reels are specifically designed for automatic operation
  • The torque motor is capable of resisting a 100% stall, providing tension on the cable to match payout speed when energised, while sustaining position with a mechanical holding brake when off
  • A single cable encompassing CCTV, power, emergency power and control supplies, and slip rings, can support a full load in the event of a hoist failure


Let's talk more about nuclear vault cranes.

The nuclear sector demands levels of safety and integrity that requires special high-integrity solutions. As safety cases are revised and become increasingly demanding, existing handling solutions will require adaptations to remain fit-for-purpose.

We have decades of experience in overhauling nuclear cranes, which come in at a fraction of the cost of a new system. Talk to us today.

Call us on +44 114 262 6199, email us at, or complete the contact form below and we'll be in touch.

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SCX Special Projects Ltd

Roman Ridge Road, Sheffield, S9 1GA, United Kingdom

t:  +44 (0)114 262 6199