Steel Wearing Out at Sizewell B

station are wearing out more quickly than expected, forcing EDF to carry
out lengthy unscheduled repairs. The French energy giant is having to keep
Sizewell B in Suffolk offline for three months longer than planned to deal
with the safety issues. The outage at the plant, capable of producing
enough electricity for 2.5 million homes or about 3 per cent of Britain’s
needs, will further restrict low-carbon nuclear power supplies amid
prolonged shutdowns at older reactors. EDF said it had found wear to some
of Sizewell’s stainless steel “thermal sleeves”, which form part of
the mechanisms that insert control rods into the reactor core to shut it
down. Experience at a reactor in France has shown that extreme wear could
eventually result in parts of the thermal sleeves coming loose and
obstructing the control rods. EDF is assessing the cause and extent of the
wear at Sizewell and how many components need to be replaced before it
seeks permission to restart the plant. It insisted the damage was
“nowhere near” the stage where it would prevent control rods
functioning, and that in any event the reactor could still be shut down
safely. EDF has said it will close Hinkley Point B in Somerset and
Hunterston B in Scotland permanently by next year, earlier than planned,
because of cracks in their graphite cores. It is also considering closing
Dungeness B in Kent as soon as this year. The plant was not scheduled to
close until 2028 but has been offline since 2018 because of corrosion.

Times 17th May 2021

https://www.thetimes.co.uk/article/sizewell-b-nuclear-plant-forced-to-stay-shut-over-safety-concerns-0d9l2mkkq