Stop Hinkley Press release
Reactor hit by more cracks
11 th October 2006
Campaigners have demanded the permanent closure of Hinkley B following news of more age-related cracks, this time in its boiler tubes. Currently one of the thirty-year old plant's twin reactors is prematurely shut down for inspections and repairs after excessive cracks were discovered in the two virtually identical reactors at Hunterston in Ayrshire.(1)
British Energy who operate the reactors at Hunterston and Hinkley Point, as well as at five other similar twin reactor AGR (Advance Gas-cooled Reactor) nuclear power stations across the UK, is bracing itself for its collective electricity power output to be permanently de-rated as reduced steam circulation to reactor turbines means reduced electricity output. In any case, extended 'outages' at Hinkley and other reactors will reduce BE's profits.
Current test results show an urgent need for thousands of metres of steel tubing to be tested. Where corroding weld joints have failed repairs will be made or, where this is not possible, tubes blanked off. The repairs and blanking off operations will require both reactors at Hinkley to be shut down for extended periods and, since the four boilers are housed inside the highly radioactive reactor pressure vessel, workers must be protected against very high doses of radiation.
The extended shut down for these repairs and the permanent de-rating of electricity output renders the economic viability of the reactors at Hinkley Point even more doubtful and delaying these works to the next scheduled close down of each reactor strains the viability of the present shaky safety case.
The news follows earlier reports of the nuclear regulator's worries over an increased risk of an accident from excessive cracking and structural weakening of the plant's graphite reactor cores.(2) A leading independent engineer suggested that the nuclear safety case, in view of the seriousness of the boiler tube cracking and potential failure leading to a massive inrush of water/steam directly into an already weakened reactor core,(3) should be thoroughly reviewed cautioning that "the combination of these two conditions could result in an increased frequency of fault and greater off-site radiological consequences well in excess of the current design-basis (acceptable) accident".
Jim Duffy, spokesman for Stop Hinkley, said: "British Energy seem hell-bent on running this reactor into the ground to win every shilling from it. That's bad enough for our safety's sakes as our searches have found the regulators have declared Hinkley to be 'defective' and at increased risk. But also workers known as 'glow-boys', due to the extra radiation they receive, will have to brave this dangerous reactor to patch it up. The Stop Hinkley Campaign demands that these ageing, crumbling reactors should immediately shut down completely and remain permanently closed."
Jim Duffy, Stop Hinkley Coordinator, 07968 974805
(1) British Energy sees further 2.0 TWh unplanned losses for delayed boiler service 18th September 2006
LONDON (AFX) - British Energy Group PLC warned today that there will be further delays to a return to service at Hunterston B and Hinkley Point B in order to complete works to fix excessive tube cracking on boilers at the power stations.
These problems are causing output reductions and the group also warned today that these delays, together with other losses, are expected to give rise to around 2.0 TWh of additional unplanned losses.
British Energy announced on Aug 16 that a boiler inspection of one unit at Hunterston B indicated a level of boiler tube cracking above that expected and that return to service would be delayed by around one month plus additional work next financial year in order to undertake repair work to a number of boiler tubes.
The work to Hunterston B is progressing, the company said today.
This will require the repair of a significant number of the defective tubes during the current outage which may reduce available capacity with the remainder being repaired during outages in the year ending March 2008 and possibly 2009. The group cautioned that this may require further work and certain modifications to the boilers.
The company believes there is not a similar degree of boiler tube cracking at Hinkley Point B R3 as that at Hunterston B. However, with a statutory outage at Hinkley Point B R3 already planned at the end of September, the company has decided it would be prudent to bring this forward and commence inspections in advance of its statutory outage planned for the end of September 2006.
The company continues to review the other unit at Hunterston B (Hunterston B R4) and the other unit at Hinkley Point B (Hinkley Point B R4) and it said these may also require further work and certain modifications to the boilers.
(2) Documents reveal hidden fears over Britain's nuclear plants
(3) Large & Associates, Brief Review of the Documents Relating to the Graphite Moderator Cores at Hinkley Point B and Other Advanced Gas-Cooled Reactors R3154 5 July 2006 - http://www.largeassociates.com/3154%20Graphite%20AGR/R3154-Graphite%20FINAL%2028%2006%2006.pdf