Nuclear Storage Pond - Waste Removal Mast & Gantry Assembly

SCX Special Projects designed and manufactured a bespoke single-stage mast and gantry assembly for a Nuclear Facility that required a method of manoeuvring a sludge retrieval vacuum pump around an Intermittent Level Waste (ILW) outdoor storage pond.

The facility required the removal of all the mobile ILW sludge that has accumulated in the 5.3m deep pond over previous years, enabling it to be stored in modern stainless steel containment and allowing the subsequent dismantling of the old pond storage structure.

SCX Special Projects’ mast assembly is mounted on an X-Y-Z travelling gantry bridge, capable of sweeping the entire length and width of the pond.

Waste removal mast under test

The seismically qualified structure incorporates the single-stage 4m tall mast, the 3.7m span travelling bridge and a 19.6m long travelling gantry.

The mast itself doesn’t enter the water, but supports a 250kg pump affixed by a free-floating pendulum to enable access into corners without overloading the structure against the sides of the pond. With a SWL capacity of 800kg the assembly is able to deploy alternative devices if required.

Rack and pinion hoist mechanism on a waste removal gantry

The cost-effective single-stage mast design takes advantage of the unlimited outdoor headroom whilst the simple design makes the solution robust and reliable. A rack & pinion hoisting mechanism raises and lowers the mast at a controlled, secure speed of 0.1m/min whilst the pump is active.

Limit switches provide boundary protection, anti-uplift brackets prevent unseating in the event of an earthquake and a storm anchor enables the mast to be locked in position in the event of high winds.

Pendant control for waste removal gantry

The mast is pendant controlled from pond-side and interfaces with the facility’s existing emergency stop system. A robust hardwired protection system provides layered protection against any potential faults.

In case of a power failure or other breakdown, an efficient but cost-effective manual recovery system is provided by detachable Tifor winches which can be used to drag the entire mast assembly back to the maintenance bay.

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SCX Special Projects Ltd

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

t:  +44 (0)114 262 6199