nuclear-news

A worsening situation of cracks in Britain’s ageing nuclear reactors

Today (10am, 1 August) Reactor 3 at the Hinkley Point B nuclear power
plant will cease generation for the last time. After the closure of Reactor
4 last month, this will finally bring all electricity production at the
Somerset site to a halt.

Although there were calls for the plant to be
granted a lifetime extension, recent revelations about the extent of
graphite core cracking at Hinkley Point B have convinced the Nuclear Free
Local Authorities that EDF Energy made the right call in sticking to its
closure plan, and the NFLA fears that core cracking will increasingly
compromise the safety of Britain’s remaining aging Advanced Gas Cooled
Reactors if their operating lifetimes are further extended.

In March 2014,
in response to a Freedom of Information request submitted via the Office of
Nuclear Regulation, EDF Energy reported that at their two oldest AGR
stations, Hunterston B (now closed) and Hinkley Point B, there were ‘less
than 10% cracked bricks in the reactor’. In 2017, the Office of Nuclear
Regulation made a major concession to EDF Energy by doubling the tolerances
so that it was now acceptable for a plant to operate with up to 20% of
graphite bricks cracked, rather than the original 10%.

However, in a
response dated May 2022 to a specific enquiry from the NFLA Secretary about
graphite cracking, it became clear that at Hinkley Point B even the raised
tolerance has been breached with the nuclear regulator reporting that in
Reactor 3, 28.8% of graphite bricks were observed to be cracked and in
Reactor 4, 22% with ‘a 99.9% confidence level’ of accuracy, with keyway
cracking observed in both.

Although overall cracking in the other AGRs is
presently reported to be under 10%, worryingly cracks in the vital keyway
bricks have been discovered at Heysham 2, Reactor 7 and at Torness, Reactor
1, which is the currently the last reactor scheduled to be closed in 2028,
suggesting a worsening situation.

 NFLA 1st Aug 2022

August 1, 2022 - Posted by Christina Macpherson | safety, UK