¿ìè¶ÌÊÓƵ

JAMES D. Watkins, Secretary of Energy in Washington, calls the job of
cleaning up contamination around the US’s nuclear plants ‘my number one
priority’. But the task threatens to overwhelm his agency’s budget. Specialists
at the Department of Energy (DOE) estimate that it will take between $100
billion and $150 billion during the next 20 years to get rid of radioactive
materials and toxic chemicals that have seeped into soil and water surrounding
the plants. That is around 50 times the department’s budget for disposal
of nuclear waste and the repair of environmental damage for 1990.

The worst problem by far is at the Hanford Reservation, in the southeastern
corner of Washington state. Hanford, operated for the government by the
Westinghouse Corporation, was the heart of the US’s production complex for
nuclear weapons during the 1950s and 1960s. Nine different nuclear reactors
operated at Hanford, along with reprocessing plants where plutonium was
separated chemically from irradiated reactor fuel.

The complex produced 190 000 cubic metres of highly radioactive waste,
which now fills 163 tanks at Hanford. Sludge has settled to the bottom of
these tanks. It is so radioactive that the heat it gives off has cracked
many of the tanks. The department estimates that some 2 million litres of
radioactive waste have leaked from the tanks.

Officials say that 149 of the tanks are too fragile to be pumped out.
Instead, the DOE plans to dry the liquid waste out, eventually turning it
into a cement-like material. Depending on how radioactive the waste then
is, it will be either removed or stored on site at Hanford. The most highly
radioactive waste will go into store in an underground repository in Yucca
Mountain, Nevada, along with spent fuel from commercial reactors.

An even larger volume of waste at Hanford, an estimated 760 billion
litres of less radioactive waste and toxic chemicals, has been dumped or
poured directly into the ground. In the earliest years of Hanford’s operation,
during the late 1940s, the bomb-makers pumped liquid waste containing more
than 4 million kilograms of plutonium directly into rocks beneath the reservation
that were saturated with water.

After that practice ended, Hanford’s managers continued to store radioactive
waste in leaky evaporation ponds, seepage basins, and burial pits. They
relied on the size of the reservation, which spreads across 1350 square
kilometres, to shield the public from ill effects.

¿ìè¶ÌÊÓƵs from the Atomic Energy Commission calculated during the 1950s
that dangerous materials would become heavily diluted in the underground
water by the time they reached the borders of the reservation, and would
pose no danger. But last year, water from one spring from Hanford that flows
into the River Columbia was found to contain 352 becquerels of strontium-90
per litre. This is a thousand times the allowable limit for drinking water
set by the Environmental Protection Agency (EPA).

The public knew little about the extent of radioactive contamination
at Hanford until a few years ago. Government secrecy had shielded the plants
from public view. ‘They had no oversight; not from the Occupational Safety
and Health Administration, not from the EPA, not from state health authorities,
not from any organisation,’ said Nat Miullo, an EPA official.

From 1984, the department came under pressure. Lawsuits filed by environmental
groups and political pressure from the governments of several states with
military nuclear plants, including Washington State, forced the department
to comply with federal environmental laws and to clean up its old waste
dumps.

The contamination produced by the DOE’s facilities is a variety of toxic
chemicals and radioactive substances. Reactors produce highly radioactive
waste, while plants that extract plutonium from irradiated uranium use a
variety of highly toxic chemicals. The entire process is ‘one of the more
potentially dangerous industrial operations in the world’, according to
Congress’s General Accounting Office.

Caught between environmental laws and a tight budget, Watkins is looking
for new technologies that could solve his problems. ‘I don’t believe the
figures (on the cost of cleanup),’ says Watkins, a retired admiral.

As an example of promising technology, Watkins points to a new incinerator,
called a plasma centrifugal reactor. The incinerator’s heat comes from a
powerful electric arc that turns air into superheated plasma at over 9000
Degree C. It turns contaminated dirt into a glass-like slag. ‘Essentially,
you are welding dirt,’ says Alan Donaldson, an engineer at the Idaho National
Engineering Laboratory (INEL). Hazardous organic chemicals are oxidised
in the heat, emerging as water vapour, carbon dioxide and hydrogen chloride.
Radioactive elements are trapped permanently in the slag. The slag would
be treated as low-level nuclear waste and buried in trenches at the DOE’s
nuclear weapons test site in Nevada.

A private company in California, Retech, originally designed the incinerator
to destroy poisonous organic chemicals. Sandoz, the Swiss chemical company,
has ordered a furnace to treat soil excavated from the ground underneath
its old plant near Basle, Switzerland. Engineers at the INEL are now testing
a prototype to see if it will handle soil from nuclear waste dumps.

At places where waste pits are highly radioactive, even digging up the
soil can be extremely hazardous. To get around this problem, engineers at
Hanford have developed a way to turn dirt into molten rock in situ.

The engineers pass five megawatts of electricity through electrodes
inserted six metres apart in the ground. The electricity heats the earth
to 2000 Degree C, turning it into a molten mass. The heat destroys organic
contamination, and the molten slag traps any poisonous or radioactive elements.

One problem is what to do with the radioactive rock after it cools.
Jan Landon of the INEL hopes that it can be turned into rubble using jackhammers
or explosives and then carted away to a waste tip.

Meanwhile, biotechnologists at the DOE’s Savannah River Plant in South
Carolina have developed a process in which bacteria break down poisonous
organic compounds. It will work where there is no radioactive contamination.

Several years ago, microbiologists found previously unknown types of
bacteria living in deep aquifers contaminated with chlorinated hydrocarbons.
They discovered that the bacteria consume methane, and that the same enzyme
that broke down methane would break down trichlorethylene (TCE), a cancer-causing
chemical that is one of the chief pollutants at Savannah River.

The biotechnologists have isolated a group of microbes that break down
TCE, and grown them in large concentrations in a ‘bioreactor’. They pump
contaminated groundwater through the bioreactor, where microbes attack the
TCE, turning it into harmless carbon dioxide and chlorine. Within two years,
a bioreactor may be in place that can handle up to 40 million litres per
day, says Terry Hazen, who manages the project.

Eventually, microbes may be injected directly into contaminated aquifers,
along with methane to sustain them in high concentrations. This effectively
turns the groundwater itself into a bioreactor.

But before a large population of microbes is pumped into the groundwater,
‘we need to know the ecology of the deep subsurface much better’, says Hazen.
‘Otherwise, it could be like introducing rabbits into Australia.’

The bacteria will not clean up radioactive contamination, which must
simply be isolated until the substances decay. Tritium, with a half-life
of only 12.3 years, decays rapidly. Plutonium lasts virtually forever, but
is not soluble in water and so tends not to migrate through the ground.
But when radioactive materials such as caesium and strontium-90 get into
the groundwater, ‘you’re stuck with it,’ says R. P. Whitfield, who is responsible
for the department’s efforts to repair environmental damage at its weapons
plants. He believes that, despite the technical advances, the DOE will have
to concentrate on the most urgent problems, and leave much of the contamination
in place.

‘DOE only has so much money,’ says Whitfield. ‘There’s probably not
enough money in the world to restore all the sites to a pristine state.’
Rather than pouring billions of dollars into a futile attempt to clean up
the hard sites, such as Savannah River, the DOE will concentrate on sites
where the task is less daunting, or where risks to public health are clear
and immediate.

For this reason, the Rocky Flats plant, near Denver, Colorado, is at
the top of the list. Groundwater contaminated with TCE and other chemicals
is seeping toward a creek that supplies water to several suburbs of Denver.
Factories at Rocky Flats machine plutonium into the precise shapes needed
for nuclear weapons. The complex does not produce highly radioactive waste,
and the job of restoring the environment around the plant is therefore relatively
straightforward.

Underground dams will contain and collect groundwater that is trapped
above a shallow layer of bedrock and seeping down a hillside. A treatment
plant that exposes the water to intense ultraviolet light will eliminate
the toxic chemicals. Soil that contains plutonium will be dug up and shipped
to a nuclear waste dump.

It will cost $400 million to clean it all up, says Kirk McKinley, who
is in charge of the task, which will take 15 or 16 years. ‘We’re going to
clean it up to green pastures,’ says McKinley. ‘A dairy farmer will be able
to come out here and let his cows graze.’

The DOE’s nuclear weapons programme has probably been the US’s worst
environmental offender in recent decades. Now that it faces the task of
cleaning up the mess, the department may become one of the most important
sponsors of advanced environmental research in the country.

The department’s funding for waste technology and environmental oversight
has increased by 50 per cent during the past two years, to $2.4 billion,
and is expected to keep rising. ‘It is my hope that the DOE will become
the world leader in environmental technology, and a valuable global resource
for environmental restoration,’ Watkins told Congress in April.

Even so, places such as Savannah River and Hanford will require ‘long-term
institutional control’, a euphemism for putting up a fence and declaring
the area off-limits to the public for several centuries. ‘It irks me,’ says
Miullo, who monitors cleanup efforts at Rocky Flats for the EPA. ‘I belong
to a generation of environmental people who cannot accept that we don’t
have the money to clean this up.’

* * *

FBI’s aircraft revealed illegal waste dumping at Rocky Flats

OFFICIALS at a plant in the US that produces nuclear weapons could face
criminal penalties for ‘environmental crimes’, according to the Department
of Justice. Earlier this month, 70 agents from the FBI carried out a surprise
search of the Rocky Flats plant in Colorado.

The raid was sparked by new evidence that Rockwell International, which
operates the plant for the government, secretly disposed of waste in violation
of federal environmental laws. The FBI charged that officials from Rockwell
and the DOE ‘knowingly and falsely stated Rocky Flats’ compliance with environmental
laws, and concealed the plant’s serious contamination’.

The FBI used an airplane equipped with infrared detectors to observe
violations of the Clean Water Act and the Resource Conservation and Recovery
Act. The infrared detector, which senses heat, revealed that an incinerator
at the plant was being used during the night, although it lacked an operating
permit. Rockwell officials had declared publicly that the incinerator was
no longer operating.

The FBI’s flights also collected evidence that hazardous chemicals were
being covertly poured into evaporation ponds at the plant that were known
to leak. Only 10 days earlier, the Environmental Protection Agency (EPA)
had denied Rockwell’s request to use the ponds.

The FBI’s agents installed remote water monitoring devices on streams
flowing through the plant. The instruments revealed periodic discharges
of chemical pollutants, which the plant’s management had not reported to
the EPA. In addition, the FBI’s overflights detected a steady discharge
of illegal waste from the plant’s sewage treatment plant into an adjoining
creek.

The FBI accused the plant’s managers of failing to file proper records
and storing waste in buildings that did not have the necessary licence.
Disclosure of the FBI’s accusations set off an uproar in the communities
around the plant. People in Broomfield, a suburb of Denver, diverted streams
from Rocky Flats away from abstraction points for the town’s water supply.

During the past five years, Colorado’s governor, Roy Romer, has threatened
several times to shut Rocky Flats down if it refused to accept state regulation.
The threat was never carried out, partly because the plant, which produces
the plutonium cores of all US nuclear weapons, is considered a crucial element
of the country’s nuclear programme.

Managers at the plant have aggressively publicised their efforts to
clean up the environment around the plant and limit future waste. But the
FBI quoted from a memo written by a DOE official in 1986 that described
‘efforts to keep the public from knowing ‘just how bad the site is’.’

Criminal penalties against officials at a military laboratory for environmental
offences would not be unprecedented. Last month, three civilian managers
at an Army plant were sentenced to three years’ probation and fines of $15
000 for illegally disposing of chemical waste.