The Nuclear Decommissioning Authority

Welsh Assembly Minister visits Trawsfynydd

22 May 2008

 

Jane Davidson, the Welsh Assembly Minister for Environment, Sustainability and Housing, visited Trawsfynydd at the end of April to get a first hand view of how nuclear waste is dealt with on the site.

She was welcomed to the site by Site Director, Phil Sprague, and his deputy Edwina Winter as well NDA Site Programme Manager Glenn Vaughan and others from the site and from the NDA.

 

Edwina Winter gave a presentation on the history of the site and this was followed by a tour of the facilities in which the Minister had expressed particular interest. She saw the Active Waste Vaults, MAC, Ponds and the new Intermediate Level Waste Store.

Trawsfynydd is a unique site as unlike the other Magnox power stations it is not located on the coast but on the banks of an inland lake in the heart of the Snowdonia National Park.

The power station generated electricity from 1965 until 1991 and was defuelled by 1995 when it entered into preparations for care and maintenance.

As part of the planning consent for the Intermediate Level Waste store, the two towering grey concrete reactor buildings will be lowered in height and remodelled to significantly reduce their visual impact.

From the outside, the site’s twin Magnox Reactor Towers, cooling ponds buildings and a multitude of ancillary facilities appear to be static in time. However the 500 staff at the site are busy stripping away the interior plant and equipment as well as dealing with the nuclear wastes.

The Minister saw the South Vault Fuel Element Debris (FED) Retrieval and Processing plant. This plant works to retrieve and immobilise the FED – the outer Magnox casing of the used fuel rods consisting mainly of twisted magnesium strips and steel springs. The FED is captured from the vault by a mechanical arm and then placed in a 3 cubic metre stainless steel box, which is then placed in a concrete over-pack, grouted with a concrete mix and stored in the basement of the reactor buildings pending transfer to the ILW store. When this work is completed the ponds complex will be ready for demolition.

Next stop was the Miscellaneous Activated Components (MAC) Retrieval and Processing. From the control room she saw how this waste is collected by a Remotely Operated Vehicle (ROV) not unlike a mini-digger and again the waste is placed in containers for interim storage.

Within the main reactor buildings the Minister saw how the 12 huge boilers have been cut up and stored. This is a major piece of work which will enable the height of the buildings to be reduced.

She was fascinated by the use of “scrabbling” machines operated remotely to shave away the contaminated concrete lining from the ponds which were emptied in 1998. This is sucked up by a vacuum cleaner and fed into metal boxes. To date a total of 30 tonnes of concrete has been packaged and sent to the Low Level Waste Repository near Drigg.

The final stop of the tour was the impressive new Intermediate Level Waste store which was completed last year and is now in the process of being commissioned. Internal cranes are being tested and trialled with empty concrete over-packs are being moved around the store.

The store, which has a design life of 150 years, contains two storage vaults, a Receipt/Maintenance Bay and an Inspection Cell. The concrete building which is shielded against the weather will house the ILW from the site until the geological repository becomes available.

After her tour, the minister had lunch with the site team, NDA officials, Trade Unions and representatives of the local Site Stakeholder Group.