Thursday 10 April 2008
Thorp Pond Elevator
Shearing in the Thorp reprocessing plant was stopped on 28 January following a mechanical breakdown. The elevator which takes fuel from the feed pond to the shear cave had failed. An engineering assessment was carried out in order to determine the cause of the breakdown and it was found that the metal elevator ropes had failed.
Despite requiring bespoke items to be manufactured, the elevator was refurbished and re-commissioned in just six weeks shaving weeks off the original estimate of six months.
A team effort was required in order to get the elevator safely back into operation in the earliest possible timescales.
When the elevator failed, all the safety systems worked as designed especially the shock absorbers which protected the fuel. The shock absorbers had to be replaced and a team of engineers, designers and contract specialists worked with the manufacturers to get the shock absorbers manufactured to the earliest timescales.
The shock absorbers were not off-the-shelf items. They were originally designed by the University of Nottingham, who still had the tooling that was used in the 1980s to manufacture the original springs for the shock absorbers.
Specialist manufactures were contracted to manufacture the springs, the bellows and assemble the shock absorbers. Considerable research was necessary to build such complex pieces of kit. Each shock absorber is over 2m long containing 80 flat form springs and rods which are protected by a set of bellows and cost £25K.
The shock absorbers were delivered to Sellafield on 6 March. The elevator was lifted out of the pond water and a specialist team of engineers worked round the clock to get it operational again. The shock absorbers were installed, the metal elevator ropes were replaced, the elevator refurbished and finally re-commissioned. Shearing of fuel started up on 17 March.
|The feed pond elevator during construction of the Thorp reprocessing facility at Sellafield.||View of elevator in Thorp’s feed pond.|