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.