[ RadSafe ] Article: At the Foot of the Rockies, Cleaning a Radioactive Wasteland

[John Jacobus]

>From the New York Times at
http://www.nytimes.com/2005/06/07/science/earth/07flat.html?
-------------
  
June 7, 2005

At the Foot of the Rockies, Cleaning a Radioactive
Wasteland

By HILLARY ROSNER 

BOULDER, Colo., June 4 - On a tallgrass prairie mesa
that seems to float midway between the Denver skyline
and the craggy Flatiron foothills, the largest
hazardous waste cleanup in American history is
entering its final stages. 

For more than three decades the mesa was home to Rocky
Flats, a high-security, top-secret factory that made
plutonium triggers for the government's nuclear
arsenal. The plant was shut down in an F.B.I. raid in
1989, and the Energy Department's contractor, Rockwell
International, pleaded guilty to illegal dumping of
radioactive waste. 

Today there are few remaining visual cues to the
history of Rocky Flats. The site - at 6,266 acres,
nearly half the size of Manhattan - is being turned
into a wildlife refuge. When it opens, in 2008 at the
earliest, the breezy meadow, populated by deer, hawks,
jackrabbits, prairie dogs and coyotes, is to have
public space for hiking, biking and horseback riding. 

Decontaminating, demolishing and disposing of Rocky
Flats - a $6.8 billion task expected to be finished in
October - has involved what Steve Gunderson,
coordinator of the cleanup for the Colorado Department
of Public Health and Environment, calls a series of
"unbelievable" technological feats. More than 39,500
containers with about 20,000 cubic yards of highly
radioactive transuranic waste have gone to their final
resting place at the Waste Isolation Pilot Plant in
Carlsbad, N.M. 

Excavators are razing the last remaining buildings as
huge water jets help contain the dust. On the site of
the building once known as the most dangerous in
America, where liquid plutonium often leaked from
faulty pipes and valves, there is only a large patch
of replanted land covered by coconut matting to
prevent erosion. 

Before they could come down, the buildings needed to
be decontaminated, which meant removing and disposing
of massive pieces of highly toxic and radioactive
equipment. The walls of some buildings were several
feet thick, and there were virtually no blueprints for
the miles of piping and ventilation systems, which had
been modified repeatedly over the years with little
documentation. 

One particular challenge was the glove boxes, the
sealed chambers in which workers handled the plutonium
using long rubber gloves that were extended in through
portholes. 

There were roughly 1,500 glove boxes at Rocky Flats,
ranging in size from that of a car to a very large
room. Because they were highly contaminated, they
would have to be shipped to New Mexico. This meant
slicing them into chunks to fit into 55-gallon drums. 

In the beginning, moon-suited workers used electric
saws to slice through the stainless steel. But after a
worker cut himself and ended up with a dangerous dose
of plutonium, the cleanup contractor, the Kaiser-Hill
Company of Golden, Colo., had "to come up with a
better, safer way to do this work," said Howard
Gilpin, its director of safety, engineering and
quality programs. 

Several innovations seemed promising, but were
ultimately discarded. In Building 771, where plutonium
was processed, workers constructed a confinement tent
where they would wheel the glove boxes and cut them
with a plasma torch. "The big problem is you're
aerosolizing plutonium when you cut it like that," Mr.
Gilpin said. "So we had to build high-efficiency air
filtration systems. But you still had workers in there
physically doing things with their hands." 

Next came a robotics system, which removed the workers
from the cutting process but kept breaking down,
requiring workers to enter the tent and fix the
problem. 

The "magical solution," Mr. Gilpin said, came in the
form of cerium nitrate, a chemical that bonds with
plutonium. Cerium lightly etches the metal of the
glove-box walls and draws the plutonium into a nitric
acid solution. Nancy Tuor, Kaiser-Hill's president and
chief executive, compared the process to "cleaning the
bathroom." 

"Spray bottles, Scotch-Brite, squeegees, rags," she
said. "They literally would go in and spray the cerium
nitrate inside the glove boxes and then just wipe off
the contamination." The rags became transuranic waste,
but the glove boxes themselves were now low-level
waste - meaning they could be shipped in larger
containers and did not need to be cut into bits. 

Some of the Rocky Flats cleanup work involved the same
puzzle-piecing skills as packing the trunk of a car.
"You can't just throw all this stuff in these cargo
containers," said Jerry Long, Kaiser-Hill's vice
president for material stewardship. "You have to know
that you won't have stuff moving around." 

Dismantling the buildings was yet another challenge.
To protect themselves from any plutonium that might be
in the air, workers fogged the rooms with sticky
fixatives that captured the radioactive materials and
pinned them to the walls. Concrete shavers were later
used to scrape off the contaminated layers. The
buildings were then demolished in various ways,
depending on their level of contamination. 

In some cases, the buildings were so strongly
reinforced that explosives were used to set off sound
waves that shook the lattices of rebar rods free of
the concrete. 

"Some of these buildings were built to withstand a
Russian bomber attack," said David Maloney, technology
director for CH2M Hill, Kaiser-Hill's parent company.
"They were designed not to be blown up. That really
gives the explosives guys something to think about." 

Beyond the physical structures, environmental
contamination in the soil and groundwater must also be
cleaned up. This has proved the biggest sticking point
with community watchdogs, who worry that the Energy
Department did not require Kaiser-Hill to dig deep
enough.

The contract set allowable levels for radioactivity in
the first three feet of soil at no more than 50
picocuries of plutonium per gram, a level at which 1
in 500,000 workers at the wildlife refuge would be at
increased risk for cancer. From three to six feet,
radioactivity can remain at 1,000 picocuries per gram,
and below six feet there are no standard limits.
Starting this month, Blackhawk helicopters outfitted
with radiation monitoring systems will fly 50 feet
over the site, back and forth in 100-foot paths,
looking for hot spots in the soil. 

The groundwater, contaminated with uranium and
industrial solvents, eventually enters the creeks that
flow across Rocky Flats. To stop this, engineers
devised a barricade to trap the water at the bottom of
a hill, then built a simple filtering system that uses
iron filings to bind the contaminants chemically.
Filtered water then flows into the creek, which
eventually feeds into the South Platte River. 

Critics of Rocky Flats and the cleanup project argue
that there is just no way to make the site safe.
"There's too much stuff scattered and thrown away out
there," said Wes McKinley, who served as grand jury
foreman in the government's investigation of Rockwell,
Rocky Flats' former contractor, and is now a member of
the Colorado Legislature. Mr. McKinley said the Energy
Department's past handling of Rocky Flats made it hard
to trust this time around. 

Representative Mark Udall, a Democrat who represents
the area in Congress, agreed that "the history of the
facility would remind all of us that we have to be
vigilant," but he said he was pleased with the cleanup
levels. An author of the bill that established the
refuge, he called it "a hidden reward for having
closed off these areas." 

Some critics worry that transforming Rocky Flats into
a wildlife refuge buries the truth of the real Rocky
Flats legacy. "The rush to normalize Rocky Flats, to
make it another chunk of open space, essentially
erases the fact that for 37 years nuclear weapons were
manufactured there," said Len Ackland, director of the
Center for Environmental Journalism at the University
of Colorado and the author of "Making a Real Killing,"
a 1999 book about Rocky Flats. But its past will not
be entirely forgotten. The 500-acre industrial area
will remain closed to the public, under Energy
Department control. 

"You don't want people to forget, 150 years from now,"
said Ms. Tuor, the Kaiser-Hill chief executive, "and
go start digging around down there." 

Copyright 2005 The New York Times Company 

+++++++++++++++++++
"Every now and then a man's mind is stretched by a new idea and never shrinks back to its original proportion." -- Oliver Wendell Holmes, Jr.

-- John
John Jacobus, MS
Certified Health Physicist
e-mail:  crispy_bird at yahoo.com


		
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