from Sunday Herald, 08 July 2001
A SERIOUS accident at a nuclear power station in southern Scotland last week sent 24 fiercely radioactive fuel rods crashing to the floor narrowly avoiding the death of workers at the plant and the release of a radioactive cloud which would have contaminated the entire region.
Managers of the Chapelcross nuclear reactors near Annan in Dumfries and Galloway are now anxiously trying to work out how to retrieve the fuel rods, which are still lying where they fell in the early hours of Thursday morning. All normal fuelling operations have been suspended at Chapelcross and at its sister station, Calder Hall, at Sellafield in Cumbria.
The nuclear plant is run by state-owned, British Nuclear Fuels (BNFL), and is Scotland's oldest nuclear power station. Home to four 50-megawatt reactors and a secretive military plant which produces radioactive tritium for Trident warheads, it has been generating electricity - and sometimes plutonium for atomic bombs - since 1959.
Nuclear engineers and regulators had initially feared that the fuel was damaged and would leak radio activity into the air. However, it is now thought this has not happened. The worst scenario would have been that the fuel caught fire endangering the lives of the plant's workers.
"This was a cock-up that was potentially very serious indeed because of the risk of a fire," said the leading independent nuclear engineer, John Large. "It put the employees at risk and there could have been a local dispersion of radioactivity."
News of the accident, which has not been publicised and is likely to lead to legal action, alarmed politicians and environmentalists. They called for a crackdown by regulators, and argued that it highlighted the dangerous folly of the government's plan to build a new generation of nuclear reactors.
"I get worried," said Fiona McLeod, the Scottish National Party's shadow deputy environment minister. "Are they cutting corners? Is there now cause for concern about the safety of Chapelcross?"
At about 1.15am on Thursday, engineers were routinely removing irradiated uranium fuel rods by remote control from reactor three, which has been shut down since April 24. They were trying to attach a cylinder containing 24 rods to a crane so that it could be lowered down a shaft into a flask and taken to a cooling pond for storage, when something went badly wrong.
The cylinder suddenly came loose and fell two-and-a-half feet onto the shaft door, which was closed. The site's emergency incident plan was put into operation, its manager, Bob Clayton, woken from his bed, and a team of expert engineers assembled. The Nuclear Installations Inspectorate (NII), the government's safety watchdog, was informed at 3.30am.
Carbon dioxide was pumped over the fallen fuel to make sure that it didn't overheat or catch fire. The area around the fuel was monitored for radiation, as were outlets from the site, and the situation was kept under close review for the next few hours.
"It was very embarrassing for BNFL, pretty annoying to the NII, but not immediately life-threatening," concluded one insider. Another pointed out that the accident could have been much worse if the shaft door had been open, because the fuel would have fallen a lot further.
Large, who is currently advising the Russian government on the safety of retrieving the Kursk nuclear submarine from the Barents sea, pointed out that it was vital to remove the fallen fuel rods from the shaft door. They were blocking the only route by which fuel could be removed from the reactor, which could become urgent if problems developed, he explained. "The story is certainly not over yet."
Two months ago Chapelcross suffered another problem during defuelling when a grab-release mechanism failed. In 1999 there were four pollution incidents at the plant, one of which resulted in the contamination of a local burn. In May 1967 radioactivity was released into the environment when fuel caught fire in a reactor and suffered a partial meltdown.
Friends of the Earth Scotland claimed that last week's accident illustrated how dangerous the nuclear industry really is . "This is the latest in a series of recent mishaps at Chapelcross and it is time the regulators cracked down, as they have done at Dounreay and Sellafield," said the environmental group's chief executive, Kevin Dunion.
"This kind of potential disaster highlights the folly of even considering building a new generation of nuclear power stations. The people of south west Scotland must make it clear they want no further part in this risky business."
BNFL has said that it expects Chapelcross to be shut down before 2010, suggesting privately that a replacement nuclear station could be built there. Two weeks ago the UK government began a review of energy policy under the energy minister Brian Wilson, which is expected to result in a programme of new nuclear power stations.
Yesterday BNFL stressed that the dropped fuel had not been damaged and that no radioactivity had leaked, an analysis that was supported by the NII and the Scottish Environment Protection Agency. BNFL and the NII have now both launched investigations into the cause of the accident, but have not yet come to any conclusions.
All refuelling operations at Chapelcross and Calder Hall had been suspended in the meantime as a precaution, a spokesman for BNFL told the Sunday Herald. "It is quite a technical challenge to recover the situation," he said, though he was confident that BNFL would manage it.
The company, which is still hoping to be privatised despite a safety scandal at its Sellafield nuclear complex last year, will now have to figure out a way of remotely lifting up the cylinder full of 24 intensely radioactive fuel rods - and then satisfy the NII that the plan is safe. According to John Large, this is likely to take at least two months.
