Hartlepool nuclear power station

Cracked reactor cores have "increased likelihood of increased risk"

NUCLEAR POWER stations in the UK are structurally defective and their continued operation is increasing the risk of a radioactive accident, according to documents written by the government's own nuclear inspectors.

The revelation, which comes just days before the Prime Minister is expected to give the go-ahead to a new generation of nuclear generators, is revealed in correspondence passed to Greenpeace between British Energy (BE), who operate the reactors, and the Nuclear Safety Directorate (NSD).

The documents, analysed by independent nuclear engineer John Large, show that the bricks which make up the reactor cores of the UK's advanced gas-cooled reactors (AGRs) are cracked. These bricks, made of graphite, help control nuclear reaction by influencing the speed of neutrons.

Channels also run through the bricks which enable key safety mechanisms, such as the entry of rods designed to shut-down the reactor in an emergency. However, the cracked graphite bricks could cause safety mechanisms to fail in a severe event and the nuclear fuel to overheat, potentially resulting in a radiological release.

In an assessment report on the safety of Hinkley Point AGR nuclear power station in Somerset, dated in April this year, the NSD conclude that there is "an increased likelihood of increased risk should we agree to continued operation".

The safety issues identified by the NSD are:

- Graphite bricks that make up nuclear reactor cores are extensively cracked;
- BE do not have a full understanding of why the reactor cores are cracked;
- BE do not know the extent of the damage;
- BE do not know how much cracking the core can sustain before it falls below the minimum safety required for a nuclear reactor.


John Large said: "The nuclear safety case for these reactors centres around the core remaining structurally sound during operation. Yet these documents show that there are considerable uncertainties about the core's ability to fulfil its crucial safety role to the extent, in my view, that reactor safety may be at a cliff edge to a very serious accident and release of radioactivity.

"In view of the increased risk presented by the continued operation of these nuclear plants, the reactors should be immediately shut down."

Stephen Tindale, executive director of Greenpeace, said: "These documents don't just show the structural damage to nuclear reactors in the UK, they show the incompetence of the Government and BE who have known about these significant cracks yet have refused to do anything about it.

"It is clear that Tony Blair should shut these dangerous reactors down. Yet it's almost as if he feels that having to turn off AGR nuclear plants to prevent a nuclear accident might be problematic just before he formally announces his staggeringly irresponsible plan to build even more nuclear plants."

Jim Duffy of the Stop Hinkley Campaign, who lives in the shadow of Hinkley Point AGR, said: "I was appalled to read these documents. It is clear that Hinkley is unsafe and should be shut immediately.

"I'm extremely worried that Tony Blair seems hell-bent on leaving my children, and future generations, exposed to the legacy of our highly dangerous nuclear industry."

There are 14 AGRs in the UK, across the following sites: Dungeness in Kent (2), Hartlepool (2), Heysham in Lancashire (4), Hinkley Point in Somerset (2), Hunterston in Ayrshire (2) and Torness in East Lothian (2).

Download the documents:

September 2003
June 2005
November 2005
April 2006
Nuclear expert John Large's review of the leaked documents


For more information, contact the Greenpeace press office on 020 7865 8255.

A brief review of a confidential leaked EdF document

Publication date: 19th May 2006

Summary
This is a brief review of a confidential EdF document that has been leaked to the public domain in France.

The EdF document relates to the projected performance of the AREVA designed Generation III EPR reactor. The first of this reactor type is presently being built at Olkiluoto in Finland and construction of a second EPR is expected to commence shortly at the established nuclear power station site at Flamanville in France.

In or about 2003 it seems that EdF prepared a statement to the Direction Générale de la Sureté Nucléaire et de la Radioprotection in response to its request to demonstrate the safety of the EPR design against the deliberate crashing of a large civil aircraft onto the nuclear island. The resulting EdF document endeavours to prove the ability of the plant to withstand such attack and it claims to do so by comparing the footprint and time sequencing of the impact of a small military (fighter) aircraft to that of a large, fully fuelled commercial airliner.

However, this leaked EdF document shows the claim to be flawed in a number of important respects: First, in that the impact signatures of the small military fighter and very much larger commercial passenger aircraft are unlikely, contrary to the reckoning of EdF, to be sufficiently similar in both time span and magnitude for the design resistance of the EPR to an accidental military aircraft strike to equally apply to a passenger airliner intentionally targeted the nuclear island of the plant - indeed, the basis of reckoning the resistance of the built structures is so grossly simplified that it is inapplicable to a real impact situation. Second, the EdF assumption that the 100 or more tonnes of aviation fuel spilt during the moment of impact would ignite and burn itself out within 2 minutes or so is entirely without justification and unproven, with there being a good possibility that highly explosive vapour would be formed within and around the structures, the deflagration of which could be severely damaging to the EPR building structures and nuclear equipment within. And, quite incredibly, one line of mitigation proposed by EdF is that the terrorist would have insufficient skills to pilot the aircraft onto the intended target, this being quite contrary to the dedicated training undertaken by the terrorists who masterminded the 9/11 attacks.