Stop Hinkley Press release

27 November 2009

Safety regulator slams reactor design

The Nuclear Installations Inspectorate (NII) today announced they have major concerns over key aspects of the safety systems in the EPR reactor proposed for Hinkley Point. They state they would not issue a license for the reactor unless the Control and Instrumentation system is fixed. A top nuclear consultant suggests the error could hold up the UK nuclear project by up to three years. (1)

In their Part 3 Report of the Generic Design Assessment , the safety regulators claimed that in the Control and Instrumentation system the computerised shut-down systems were not sufficiently separated from the normal operating systems. Consequently they aired their concern that a fault could affect the performance of crucial safety systems. They raised a 'Regulatory Issue' or red flag over the issue, the highest warning they can give to a nuclear operator.

The Control and Instrumentation system, if not acceptable, could be replaced with a version from an older reactor the 'N4' but the N4's control system was itself found to be faulty and so it used an even older version from an earlier reactor, the '1300 MWe' built in the 1980's. EdF have suggested using a hard-wired system to replace the computerised control of the safety systems but this is an early proposal with no detail attached.

The NII pin-pointed other areas of concern with the reactor design:

•  More work was required on the prevention of cracks in the fuel cladding due to thermal stress. This is very important as the 'high burn up fuel' which will be deployed in the EPR is hotter and more radioactive than fuel used in previous Pressurised Water Designs. It is crucial that the fuel is effectively contained within its cladding.

•  Analysis of the human factor in the safety of the reactor was seen as being unclear in the design proposals. This section deals with how workers or others might deliberately or for other reasons sabotage the reactor. EdF were told to put more effort into their arguments to back up their safety claims.

•  Managing radioactive waste: an assessment on the disposability of the highly radioactive spent fuel arrived too late for consideration for this part of the assessment. Campaigners are keen to examine this area as the spent fuel will be twice as hot and twice as radioactive as from conventional PWRs and will need to stay on site at Hinkley for an estimated 160 years before it can be physically put in 'permanent' containers for eventual movement to a hoped for (but as yet unplanned) Deep Geological Repository.

•  Design changes: The regulators state they find it difficult keeping track with a reactor design which is not complete. As it is currently being built on two sites in Finland and France , the designs are frequently changed. The regulator has asked for a 'frozen' design as of 2008 but acceded that changes can be incorporated.

•  Categorisation & classification: The EPR design has been found to be not entirely in alignment with international good practice eg on mechanical systems where there is no classification system for delivery of a safe function.

•  Exclusions: The regulators have conceded that construction could conceivably go ahead despite outstanding areas of concern but only up to the point where the specific concern becomes relevant. There is some risk to EdF here but also the regulator would be under mounting pressure to give way once the momentum of the project had reached a certain point.

Jim Duffy, spokesman for Stop Hinkley said:

"This reactor has had an unlucky history. It was based on the earlier 'N4' reactor of which only four were ever built due to thermal fatigue flaws in the important heat removal system. They took between 16 and 19 years to reach operational output."

"Its construction in Finland is nearly four years late with 3,000 recorded building errors(2). The French version is currently two years behind schedule and now the UK regulators are as critical as they can be over the risks with its computerised safety system. EdF may need to apply a thirty year old system to replace it or simply hard-wire it. This is hardly 'state-of-the-art' that EdF boasts of their new reactor design. It makes you wonder how it got approval to get as far as it has in Finland and France ."

"We could avoid a great waste of time and money by a change of direction and fully backing renewables before that's too late to help stop climate change."

Jim Duffy, Stop Hinkley Coordinator