Scope: Remove and dispose of steel shaft seals on an offshore barrier
Location: Bradwell Nuclear Power Station, Essex
In March we took on a challenging project to remove and dispose of four six tonne steel shaft seals from an offshore barrier at Bradwell NPS for Magnox, after a previous contractors earlier attempt had ended in catastrophic failure. Sixty years of exposure to sea spray and extreme weather conditions had left the seals and the single central lifting eye in a state of deterioration and we had to attach an additional eight lifting eyes to distribute the load evenly.
The seals were initially raised 500mm and lowered onto timber blocks in preparation for the final vessel mounted crane lift, during which the seals would be lowered onto an adjacent barge for subsequent disposal.
The works were made all the more challenging by adverse weather conditions at the critical moment when precise tidal conditions, vessel availability and good weather all had to synchronise for the final lifting operation to succeed.
Our chief design engineer designed the four lightweight GRP covers that were to replace the steel plugs.
The design criterion was: The covers must be lightweight and easily assembled/installed on site, with a lock-able central access hatch to facilitate subsequent shaft access and further investigatory works and they must have a minimum life-span of 30 years.
Our excellent team responsible for the seal removal and subsequent GRP cover installation was headed-up by Mat Perrott, who despite harsh working conditions, weather downtime and running changes to both the seal removal and cover installation methodologies, managed to bring the project in on time and on budget.
Testimonial: We had been using Tunnel Vision on a number of high-profile projects and were impressed by their attitude and ability to achieve great results under difficult conditions , so when a previous companies attempt to remove the offshore cooling pipe shaft seals failed, we knew who to call.
Again they did a fantastic job under harsh working conditions and got us out of a difficult situation.
I would recommend them to anyone.
Steve Knott, Magnox Sites