BE restarts Hartlepool 2 after BCU repairs

Monday, 23 February 2009

British Energy (BE) has restarted the third of the four Advanced Gas-cooled Reactors (AGRs) that have been out of service for boiler closure unit (BCU) repairs. The final AGR is expected to restart soon.
 

Hartlepool (Image: BE)

The Hartlepool 2 unit, having been repaired and received regulatory approval, was restarted on 19 February. However, due to an unspecified problem, the reactor was shut down again the following day. The 605 MWe unit was then restarted on 21 February and has since been increasing power output.
 
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.
 
The last of the AGRs, Heysham 1 unit 2, is expected to be restarted within the next few weeks.