* Sellafield tells non-essential staff to stay at home
* Later says natural radon gas caused alert, no operating
* Britain says no danger to the public or workers
By Belinda Goldsmith
SELLAFIELD, England, Jan 31 Sellafield, the
largest nuclear site in Europe, declared an alert on Friday
after discovering higher than usual levels of radioactivity, but
later called it off, saying naturally occurring radon gas had
triggered the alarm.
The fuel reprocessing plant in northwest England, the site
of Britain's worst nuclear accident in 1957 and once the
producer of plutonium for nuclear bombs, told non-essential
staff to stay away after the abnormality was detected overnight.
The plant's operating company said there was nothing wrong
with its operations, but for several hours the cause of the
higher reading at an air monitor near a perimeter fence was
unclear, raising fears of a radioactive leak.
Before midday, the operating company, Sellafield Ltd, said
it had found that radon, a naturally occurring radioactive gas
that comes from rocks and soil, was the cause.
"This is a very rare occurrence and the alert is over.
Everything will be back to normal on Saturday," said a spokesman
from the Nuclear Decommissioning Authority (NDA), the public
sector body that owns the site.
The ageing facility, by Britain's picturesque Lake District
on the coast of the Irish Sea in northwest England, continued to
operate normally during the morning and the operator and the
government said there was no risk to the public.
It was the first time local inhabitants could recall staff
being sent home.
"It worries everyone but we try not to panic," said Robyn
Turner, 42, who works in a supermarket in the nearby coastal
village of Seascale. "You just have to trust that they know what
Managers at Sellafield, a large, fenced-off site of grey
buildings, industrial cylinders and cooling towers about 300
miles (480 km) northwest of London, said the decision to keep
staff at home was conservative but "prudent".
Set up after World War Two, Sellafield was once the source
of plutonium for Britain's nuclear bombs.
It was also the site of Britain's worst nuclear accident,
the October 1957 Windscale fire, when a plutonium reactor burned
for five days, belching radiation into the atmosphere.
Sellafield is now the site of a civilian nuclear power
station being decommissioned by a consortium of UK company Amec
, France's Areva, and U.S. firm URS.
One of two nuclear fuel reprocessing plants in Europe along
with Areva's La Hague plant in France, Sellafield also receives
spent fuel from power plants across the world, including Japan.
It employs more than 10,000 people.
Nuclear experts and academics had said initial information
available publicly indicated this was a minor incident with
little in common with the 2011 Fukushima and 1986 Chernobyl
"This is a prudent precaution until the cause is known and
the situation rectified," said Richard Wakeford, a professor of
epidemiology at the University of Manchester, of the initial
decision to withdraw non-essential staff.
"It's a different situation here than it was at Fukushima
and Chernobyl because you haven't got operating reactors."
But the increased radiation reading, even from radon, could
increase scrutiny of Sellafield's safety record.
David Webb, chairman of the Yorkshire division of the
Campaign for Nuclear Disarmament (CND), said any incident was
always worrying because it raised concerns about standards.
"They will always say there is no risk but you can rarely
prove a direct connection between such incidents and people's
health," he told Reuters, citing reports indicating there had
been 21 leaks at Sellafield in the past 60 years.
Environmental group Greenpeace says Sellafield has the
highest concentration of radioactivity on the planet and that
its reprocessing plants discharge some 8 million litres of
nuclear waste into the sea each day.
It also contains what its deputy managing director George
Beveridge described in 2009 as "the most hazardous industrial
building in western Europe", housing a 150-metre-long (490 feet)
pond used to store spent nuclear fuel.
In April 2005, leaked radioactive waste was discovered from
Sellafield's THORP reprocessing plant which may have started as
early as August 2004. It was categorised as a level 3 event on
the International Nuclear Event Scale and resulted in fines.
British Prime Minister David Cameron has thrown his weight
behind building new nuclear power stations as a way to replace
ageing coal and nuclear power plants.
The government last year signed a $26 billion deal to build
a new nuclear plant in southwest England with the support of
France's EDF and two Chinese partners.
NuGen, a nuclear new build joint venture between Japan's
Toshiba and France's GDF Suez, owns a site adjacent to the
Sellafield reprocessing plant to build a new nuclear power
station. The group wants to build three reactors on the site,
the first scheduled for service in 2024.