Reassurances given over safety of nuclear reactor at Sizewell B

Text of original article that appeared in the East Anglian Daily Times and the letter from Charles Barnett in response.

The UK nuclear safety watchdog is “confident” that Sizewell B is clear of the defects found in two Belgium reactors and cannot justify ordering the plant to be shut down for an early inspection, a senior official told a public meeting.

Dr Gareth Hopkin, the Office for Nuclear Regulation’s specialist inspector for structural integrity, said the confidence was based on the knowledge that the Sizewell pressure vessel was made of a better quality steel and had been subject to more thorough and more extensive pre-operational tests.

The meeting, at Leiston, organised by the Sizewell Stakeholders Group, was aimed at addressing public concern about possible implications for the Suffolk plant arising from the discovery of defects =- cracks caused by small explosions called hydrogen bursts – in a Belgium reactor pressure vessels.

The Sut Down Sizewell Campaign has called for the Sizewell B reactor to be shut down this year for a full-scale inspection, currently planned for 2016.

In Belgium. both the reactors involved, at Doel and Tihange were shut down after cracks were discovered in 2012 but both have since been allowed to re-start, subject to revised operating conditions.

Dr Hopkins said the Sizewell pressure vessel had been manufactured to a higher specification than those supplied to Belgium and had been more thoroughly tested.

The Sizewell B forgings had also been created by a different manufacturer and had undergone hydrogen removal treatment, unlike those in Belgium.

Dr Hopkings said in the light of the discovery of the Doel and Tihange defects, EDF Energy which owns and operated SIzewell B, had volunteered to carry out extra tests during the plant’s scheduled 10 year shutdown for inspections and maintenance.

Ordering an earlier inspection could not be justified.

He said: “”ONR does not consider it appropriate to bring forward the inspections planned for the spring of 2016. Following and extensive and detailed review of the vessle manufacturing recodes, we consider the controls put in place during manufacture to both avoid and detect hydrogen bursts were appropriate”.

East Anglian Daily Times 8 March 2014

Concern over reactor vessel

Sir – I wish to comment on your account (march 8) of the public meeting in Leiston (March 5) headed ‘Reassurance given over the safety of nuclear reactor pressure vessel at Sizewell B’  addressed by two senior inspectors from the Office of Nuclear Regulations (ONE).

A the meeting , as Chariman of Shut Down Sizewell Campaign, I said we have been pressing since December 2012 for the immediate shut down of Sizewell B so that its reactor pressure vessel (RPV)be tested to ensure that it did not have the serious faults found in two Belgium reactors – faults which could lead to severe loss of radioactivity.

I regret to say we were unconvinced by the two inspectors ‘reassurance’ abd wgi seeened ti be merely reactive to the possibility of faults in Sizewell B’s RPV, rather than proactive, which is surely their role.

They relied on EDF (the operators) supplying paperwork written some 20 years ago covering the forging (and inspection of only part) of the RPV and an inadequate in service inspection carried out in 2005, nine years ago, when only part of the RPV was subject to ultrasonic testing.

Furthermore, I pointed out that EDF were now prepared to carry out a full ultrasonic test of B’s RPV but not until 2016 – the next scheduled 10 year periodic safety review – far too late.

Such an office, as I said, but only in two years time, gives us further disquiet. It implicitly shows there are good grounds for an investigation now.

I also pointed out that, subsequent to the Belgium revelations in 2012, a further two reactors of the same basic design in Carolina, America, had been found to have cracks in their RPVs and consequently were shut down for repairs – an event denied by the ONR inspectors.

Charles Barnett, Chaiman, Shut Down Sizewell Campaign. East Anglian Daily TImes Saturday 15 March, 2014