BE brings two AGRs back online
British Energy has restarted two of the four Advanced Gas-cooled Reactors that have been out of service for almost one-and-a-half years for boiler closure unit (BCU) repairs. The other two are expected to restart soon.
British Energy (BE) has restarted two of the four Advanced Gas-cooled Reactors (AGRs) that have been out of service for almost one-and-a-half years for boiler closure unit (BCU) repairs. The other two are expected to restart soon.
The BCUs which have been causing problems are unique to the Hartlepool and the Heysham 1 sites. AGRs have their eight boilers (steam generators) fitted inside the reactor's reinforced concrete containment structure and wire windings in the BCUs form part of the pressure boundary. A broken wire winding was discovered on a BCU at Hartlepool unit 1 during a planned inspection in September 2007, and BE decided to take its sister units at Hartlepool and Heysham 1 out of service for inspection and assessment.
The BCUs cannot be replaced, so BE is placing circumferential bands around the BCUs to 'lock in and enhance the existing pre-stress'. Regulatory approval to begin installation of circumferential bands was received on 21 August 2008. However, BE reported that installation of the circumferential bands on the lead reactor (Heysham 1 unit 1) had taken longer than originally planned. All four reactors had previously been expected to resume operation by the end of 2008, but BE announced in October that it did not expect the first of the reactors to return to service until early 2009.
On 26 January, BE said that, having completed engineering modifications, Hartlepool unit 1 was reconnected to the grid after receiving regulatory approval to return to service.
Heysham 1 unit 1 was also returned to service on 2 February having also completed engineering modifications and receiving regulatory approval.
In a statement, BE said: "Following completion of the engineering modification work and upon receipt of the necessary regulatory clearance, the company expects to return Reactor 2 at Hartlepool power station and Reactor 2 at Heysham 1 power station to service in a phased process over the coming weeks."
Whilst the four reactors at Hartlepool and Heysham 1 have been offline due to the BCU issue, BE has taken the opportunity to carry out work originally scheduled for future outages. This work has included the replacement of some 3 kilometres of cast iron cooling water pipe work at both plants.
