Stop Hinkley Press Release

End of the road for Hinkley

25 October 2006

The nuclear safety regulators have, under the Freedom of Information Act, released a document saying that Hinkley B (and Hunterston B) is unable to make a safety case in respect of its graphite reactor cores at the end of its current licensing period, possibly this year.

The Nuclear Installation Inspectorate report says clearly that a safety case cannot currently be made for Hinkley (and Hunterston in Ayrshire) for a forthcoming period and outlines the engineering dangers: that most graphite bricks will crack in the near future, some slicing in half, thus jeopardising the safe running if the reactor.

It is commonly known that, if a graphite brick goes out of line it can impair the movement of fuel elements and control rods. But it can also cause localised overheating, creating a fuel-fire and a subsequent release of fissile material. Previous NII reports have suggested this extreme event is unlikely but asserted that from operating the plant longer there is an increased likelihood of an increased risk (of an accident). This report leaves much less to the imagination.

Key excerpts from the NII Assessment Report 61/06 (1) dated 18th July 2006 follow:

"BE predict that during the period covered by Periodic Safety Review 2 (PSR2) [ thought to be 20 to 30 years of operating- JD ] the majority of fuel moderator bricks will develop a single through-thickness crack from a keyway root. Some of these may develop a second keyway root crack such that the brick may be in halves....

...Therefore brick cracking could affect channel straightness and the ability of the graphite core to meet its fundamental nuclear safety requirements...

PSR2 recognises that core lifetime is probably the dominant station life-limiting feature and that it is currently not possible to make a safety case for the graphite core to [date deleted] (suggest 2007 -JD).

The current safety case will expire during the PSR - 2 period..."

This means Hinkley B should very soon shut down permanently, being unable to have its risks justified.

Boiler tubes

The report is especially crucial now, as severe boiler tube cracking has been discovered in the reactors, greatly compounding the risk from the known damage in the reactor core. Hinkley's cracked boiler tubes (inside the nuclear reactor and therefore highly dangerous, especially given the damaged condition of the reactor bricks) were not inspected this summer and are barely referred to in the FoI documents. Even railway steam engine boilers need a regular certificate as steam explosions can kill bystanders. But British Energy has neglected this key maintenance at Hinkley.

There are four boilers inside each reactor pressure vessel at Hinkley. A serial cracking open of these 'creep fatigue cracks' during a rapid cooling process eg during an emergency shut-down, would release a lot of steam at double the coolant pressure into the pressure vessel. This would create a shock-wave from the bottom of the reactor upwards and potentially dislodge some cracked graphite bricks with the consequences outlined above. Moreover, up to a hundred fuel pins could shatter in the process, a graphite fire would ignite which would be vented though the pressure vessel valves, emitting copious amounts of fissile material. Such a fire would be virtually impossible to douse.

Furthermore the regulators should have been ensuring that BE were sticking to this straightforward maintenance programme and are thus also at fault: a scandal of huge proportions.

Stop Hinkley's analysis:

1. BE are likely to go bankrupt with the sudden loss of two nuclear power stations and others prematurely lining up to follow through the same age-related cracking.

2. The Government will need to re-nationalise the company as, under EU law, they cannot bail out BE twice.

3. The taxpayer will have to shoulder the bill for decommissioning the eight BE plants at GBP 1 billion a piece. Currently we were only expected to pay 5% of this cost under the last restructuring package.

Our questions:

Where does this leave a supposed non-subsidised nuclear new-build programme?...with BE as Government favoured hopefuls in operating new plant?...with highly respected nuclear safety regulators who in reality neglect their role?        ...In the gutter?

Both Oldbury's reactors (near Bristol) are still shut: reactor 1 after more than a year and reactor 2 since August 31st, due to graphite corrosion. This has reached 34.5% in each reactor and BNFL have not provided satisfactory analysis of graphite samples to convince the NII to licence them to restart. Stop Hinkley was told in April these would be ready in July or August. We're now in October with no suggestion of a restart, nor any announcement of the surely inevitable permanent closure.

Jim Duffy, Stop Hinkley spokesman said: "Here we have a graphic description of the damage to the reactor core, which the regulators say fails to meet fundamental nuclear safety requirements. This was written before the surprise discovery of severe boiler tube cracks which greatly compounds the safety risk. Reading it all made a cold shiver run down my spine. Hinkley must be finished now."

Jim Duffy, 0208 395 6191 or 07968 974805

Notes: For this document go to: www.hse.gov..uk/foi/releases/ar6106.pdf

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