Dungeness brought back on-line

?At the Dungeness B nuclear power station the outage programme is planned every three years at each of the reactors. For this, Babcock recently worked with an EDF Energy team, and contractors, such as Doosan, which undertook similar programmes to overhaul the boilers.

According to Babcock, over 100 of its personnel were on site to undertake the project. This involved the maintenance of rotating plant including gearboxes, clutch assemblies, motors and cartridge units on the gas circulators, for which Babcock is the original equipment manufacturer.

The Babcock site team fully stripped two of the circulators down to their component parts (using dedicated lifting equipment), and inspected the equipment for wear. The main motors and pony motors driving the circulators were removed and sent off-site for specialist maintenance.

All affected gaskets and sealing arrangements were replaced in a leak mitigation project to minimise oil leaks. Two other gas circulators were visually inspected and tested to confirm that they were working satisfactorily.

A further partial stripdown of another gas circulator - involving a full penetration tube strip down to replace the running seal - was also undertaken before the start of the main outage by a Babcock team mobilised in advance. This allowed the other reactor to be brought up to full power at the end of March 2012.

Babcock is also the fuel route contractor for Dungeness B power station, based on the company’s knowledge of fuel route design. In this role,

The company maintains a full-time team of some 40 people year-round on site. They are working alongside EDF Energy staff to optimise the fuel handling within the station to increase power generation, by maintaining and modifying key items of equipment, such as the fuel handling machine.

Babcock’s delivery of this project, included the procurement of new equipment, such as a cantilever lifting beam, and the development of a trolley to remove the shield block, rather than bringing a mobile crane to site. This, it said, saved several days on the critical path of the outage, as well as reducing direct costs.

The working relationship between Babcock and EDF Energy has been an important element in completing all planned works on this outage ahead of schedule, according to Sue Shaw, Babcock business manager.