IAEA pressed on Hunterston restart safety case

News from the Celtic League:

The Celtic League have written to the IAEA (Acting) Secretary General Cornel Feruta asking if the UN nuclear safety agency endorses a decision of the UK ONR to relax safety rules to allow Hunterston Power Station to be restarted:

“The Acting Secretary General
Cornel Feruta
International Atomic Energy Agency
PO Box 100
1400 Vienna
Austria

By email

20/08/2019

Dear Sir

I write with reference to the decision if the Office for Nuclear Regulation to allow the restart of Hunterston B Power Station in Ayrshire Scotland. The station had been taken out of service because of cracking of graphite bricks in the reactor core.

I note from the Project Assessment Report (PAR) that the decision is based not on any improvement but a relaxation (doubling) of the safety threshold (quote):

“The safety case is based upon an increase in the operational allowance to 700 axial cracks and an upper safety limit of 1331 axially cracked bricks. The safety case also takes into account graphite bricks with two axial cracks (doubly cracked bricks) and the potential for bricks with three or more axial cracks (multiply cracked bricks). EDF Energy NGL’s view is that these changes are justified through developments in the assessments used to predict how a cracked core will perform under normal operation, faults and seismic loading (known as Damage Tolerance Assessments).”

The full PAR is at this link:

http://www.onr.org.uk/pars/2019/hunterston-b-19-004.pdf

Can I ask if the IAEA is aware of this issue ad indeed if you endorse the relaxation of safety thresholds in this way by nuclear plant operators.

The history of cracking of graphite core bricks in UK reactors is well documented and indeed other reactors now could - if the ONR deem it necessary - relax safety thresholds.

It is a well known fact that the UK at the present time is struggling to meet its electricity grid demand and that resilience is limited as was evidenced by widespread power cuts recently.

I do hope that nuclear safety is not being compromised to ensure security of demand for the UK next winter and the Celtic League would urge the IAEA to assess the documentation on which the United Kingdom ONR have reached their decision.

I think it would be reassuring if a reputable body such as IAEA endorsed this safety case.

Yours sincerely.

Bernard Moffatt

Assistant General Secretary
Celtic League”

Image: IAEA building Vienna - inset Cornel Feruta

Bernard Moffatt

Celtic League