- There is a 50% chance of a major accident while the US
government attempts to clean up its dirtiest nuclear site over the next
three decades, a new study concludes. Even without an accident, the groundwater,
a nearby river and fish could end up badly contaminated.
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- A decision to fast-track the rehabilitation of the vast
Hanford nuclear complex in Washington State poses dangers and could lead
to "costly and time-consuming mistakes", says Bob Alvarez, formerly
a senior environmental adviser to the Clinton administration. His study
is due to be published in the September issue of Princeton University's
peer-reviewed journal, Science and Global Security.
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- Over the last 50 years nine reactors at the 1500-square-kilometre
site have produced 67 tonnes of plutonium for the US nuclear weapons programme.
In 2002 the US Department of Energy (DOE) embarked on a 30-year, $50 billion
clean-up, which includes emptying more than 190 million litres of liquid
radioactive waste from 177 underground tanks.
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- "The costs, complexity and risks of the Hanford
high-level waste project rival those of the US manned space programme,
but have far greater potential consequences to the human environment,"
says Alvarez, who is now with the Institute for Policy Studies in Washington
DC.
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- "Political considerations"
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- Allyn Boldt, who was a senior chemical engineer at Hanford
for 25 years, fears that any problems at the site will jeopardise the expansion
of nuclear power he believes is necessary to meet the world's future energy
needs. "The clean-up decisions at Hanford are being made by administrators
driven by political and career considerations," he told New Scientist.
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- That may not lead to the best decisions, he says. Even
if the clean-up goes according to plan, Boldt claims there will still be
260 square kilometres of groundwater exceeding drinking water safety limits
for over 10,000 years. And ground contamination means "several square
miles will be a national sacrifice zone that cannot be excavated for hundreds
of thousands of years", he says.
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- The DOE accepts that it faces major challenges at Hanford
but stresses that since 2000 it has made good progress on what it calls
"the world's largest environmental clean-up project". A new treatment
plant is more than 25% built and will be ready to take high-level waste
by 2011.
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- The aim is to complete the clean-up by 2035, 35 years
earlier than originally planned. This will reduce the danger to the environment,
as well as cutting the cost, argues a DOE spokeswoman.
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- "The accelerated progress we've been making would
not be possible without a corresponding improvement in safety," she
says. "We are working safer today than we were three or four years
ago."
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- Steam explosion
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- According to Alvarez's study, a risk estimate from US
Nuclear Regulatory Commission implies that there is a 50-50 chance of a
major radiation or chemical accident at Hanford over 28 years of operation.
The worst hazard is from a steam explosion at one of the melters used to
mix radioactive waste with molten glass.
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- "DOE's experience with glass melters does not inspire
confidence," Alvarez observes. "Since 1991 there have been at
least eight melter-related accidents and failures at DOE sites, including
two steam explosions."
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- He also highlights numerous other risks, including the
potential build-up of flammable gases in Hanford's underground storage
tanks. In October 2003, one tank was discovered to contain sufficient concentrations
hydrogen to burn - after it had been declared safe.
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- The tanks, most of which date from the Cold War, are
also increasingly unreliable, Alvarez alleges. Nearly four million litres
of radioactive waste have leaked from a third of them and contaminated
the groundwater.
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- A plan to dispose of iodine-129 at Hanford risks further
contamination in breach of the Environment Protection Agency's safety limits
for drinking water, he warns. Fish from the Columbia River, which flows
through the site, are an important part of the diet for thousands of neighbouring
native Americans.
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- Finally, Alvarez says that almost a fifth of the huge
amount of radioactivity at Hanford could end up being left at the site,
including six times more caesium-137 and over a hundred times more strontium-90
than were released by the 1986 accident at the Chernobyl nuclear plant
in Ukraine. According to the DOE, there is not enough room for all the
waste at the proposed repository at Yucca Mountain in Nevada.
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