Speedy valve work keeps shutdown short

Edited by the Engineeringtalk editorial team Aug 26, 2008

Almost 750 valves were overhauled at the UK's largest Magnox nuclear power station during the annual outage, and involved work in the turbine, boiler and numerous other areas of the plant.

Almost 750 valves were successfully overhauled recently, on-site at the UK's largest Magnox nuclear power station, by specialist engineering and technical services company Furmanite, helping to keep the major shutdown on-schedule.

The contract was undertaken at Magnox North's Wylfa site on Anglesey in North Wales, during the annual outage, and involved work in the turbine, boiler and numerous other areas of the plant.

The substantial valve overhaul programme included safety valves ranging in sise from 1.5 to 10 inches, isolation valves from 0.5 to 21in, and butterfly valves up to 50in in sise.

The majority of these valves were overhauled on-site, including disassembling, inspection, lapping and reassembling, representing efficiency savings by avoiding the need to remove several hundred valves to the workshop.

The remaining valves were taken to Furmanite's Warrington workshop to be overhauled and to allow insurance witnessing and approval by Zurich following commissioning on Furmanite's test rig.

The work was carried out by Furmanite SQEP (Suitably Qualified and Experienced Personnel) technicians who have been audited and are experienced in working safely as part of a team in nuclear environments.

They were supported by a site management team (comprising a site manager, quality engineer, health and safety engineer, supervisors and a technical clerk) who were on site before, during and after the outage.

Furmanite Outage Manager Gary Marsh explained: "We were called in to undertake this work as a result of our excellent track record in previous shutdowns on the site, the relationship we have built up with the Wylfa management, and the continuing improvement we have demonstrated in helping the site with the outage year on year".

"Our site team was proud to be highly commended for meeting Magnox North's stringent safety requirements, successfully completing the scope of works, and for the use of operational experience and feedback".

"This included working with the station staff to look for ways in which improvements could be made and to ensure that the job was performed correctly and safely first time".

Commenting on the programme, Magnox Contract Manager Peter Malone said: "The annual outage is an extremely important period for Wylfa site".

"It enables us to carry out vital statutory checks and maintenance that we are otherwise unable to do when the station is on-load".

"Any work, by our contractors, which can reduce the amount of time we spend not generating electricity is extremely useful and contributes to our overall efficiency and performance".

"This year Furmanite has provided excellent site management, site support, technical knowledge and safety culture to ensure a successful outage".

Wylfa is one of ten Magnox sites at various stages of their operational lifecycle being managed by EnergySolutions on behalf of the owners, the Nuclear Decommissioning Authority (NDA).

The site started generating electricity in 1971 and on a typical day it supplies 23 million kilowatt-hours - enough to meet the electricity needs of two cities the sise of Liverpool or Manchester.