BE finds another damaged wire at an AGR

22 November 2007

As investigations continue into the condition of wire windings in the boiler closure units (BCUs) of some of British Energy's (BE's) Advanced Gas Reactors (AGRs), the company announced that a damaged wire had been found at Heysham 1 Reactor 2. In a statement, BE said, "Inspections of Heysham 1 Reactor 2 have so far not shown any evidence of broken wires in the BCU. However, there is evidence from the radiographic inspections that are in progress that one wire is showing signs of thinning." The company reported on 22 October that "an issue relating to a wire winding" was discovered at its Hartlepool Reactor 1 during a planned inspection of boiler closure units. BE subsequently shut down its Hartlepool 2 and both Heysham 1 reactors, which share the same design of BCU. The company previously announced that initial results of inspections at Heysham 1 Reactor 1 had identified a similar issue with the wire windings, saying that "one wire has failed as a result of corrosion." An inspection of Hartlepool 2 will start soon. BE said that the discovery of a thinning wire at Heysham 1 Reactor 2 "will likely place the reactor in the same category as Hartlepool Reactor 1 and Heysham 1 Reactor 1 for a return to service safety case and/or remedial repairs." In an AGR, eight boilers are within the concrete pressure vessel that safely contains the reactor core and potentially dangerous materials. The steel and concrete boiler closure units form part of the reactor pressure boundary and are pre-stressed with nine layers of wire windings. It is the condition of this wire that BE is investigating.

Further information

British Energy

WNA's Nuclear Power in the United Kingdom information paper

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WNN: Safety reviews complete for Hunterston B and Hinkley Point B

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