ARTICLE 

A Big Job: Cleaning Up Nation's Nuclear Waste  

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by Harold Kennedy  

A decade after the end of the nuclear arms race between the United States and the Soviet Union, this nation gradually is coming to grips with a chilling fact of life.

Contamination left over from the development over the past half century of thousands of nuclear weapons has saddled the United States with one of the world's biggest environmental problems. Cleaning up will cost billions of dollars and take decades to complete.

During the Cold War, nuclear arms production and related activities took place at more than 20,000 facilities across the country. But the Soviet Union, the main nuclear threat to the United States, disintegrated in the late 1980s. Since then-although this nation continues to maintain a reduced stockpile of nuclear weapons and a limited production capability-production itself has largely ceased.

The entire production complex is being downsized. Many materials and facilities once considered vital to national defense have been declared excess baggage. Other sites have shifted their focus from weapons production to environmental restoration, waste management, nuclear material stabilization, and technology development.

The Department of Energy (DOE)-which inherited responsibility for nuclear weapons production activities when it was created in 1977-now has been ordered to reduce the damage caused by previous decades of nuclear production. The damage is considerable, according to Gerald Boyd, acting deputy assistant secretary of energy for science and technology.

"Cleanup of the radioactive, chemical and other hazardous waste left after 50 years of U.S. production of nuclear weapons is the largest environmental management program in the world," he said.

A recent report by DOE's Office of Environmental Management identified 353 projects at 53 sites across the country that require cleanup.

Billions of Dollars
Cleaning up these sites will cost a projected $147 billion and will take until the year 2070 to complete, the report estimated.

The department currently manages all of the most radioactive waste-known as "high-level" waste-at the four sites where it was originally generated. These include Hanford Site, near Richland, Washington; the Idaho National Engineering and Environmental Laboratory, near Idaho Falls; Savannah River Site, in Aiken, South Carolina, and the West Valley Demonstration Project in West Valley, New York.

At Hanford, highly radioactive waste is stored underground in 149 single-shell tanks and 28 double-shell versions. Some tanks have leaked, releasing a million gallons of waste to the environment.

Savannah River has only about half as much high-level waste, but it contains about one and a half times the amount of radioactivity.

The high-level waste in Idaho is stored both in underground tanks and bins.

The West Valley Demonstration Project was the site of the only commercial nuclear fuel reprocessing plant to operate in the United States. The waste there was not produced by weapons production, and it is much less radioactive than that found at the other three sites.

Transuranic (TRU) waste-managed at 23 locations in 16 states-is less radioactive than high-level material. But it is still hazardous, and it can remain active for hundreds of thousands of years.

Under federal law, both of these kinds of waste are to be treated to produce solid material suitable for disposal and placed in deep, underground repositories in order to minimize environmental damage. Where they have been proposed, however, underground repositories have generated opposition from environmentalists and others who fear that radiation will leak out and contaminant nearby populated areas.

Underground Disposal
The first of these repositories-the Waste Isolation Pilot Plant (WIPP), near Carlsbad, New Mexico-is ready to begin operating. Occupying 16 square miles of land, WIPP lies 2,150 feet below the earth's surface in bedded salt. The National Academy of Sciences, back in the 1950s, recommended disposal of radioactive waste in stable geologic formations, such as deep salt beds. But WIPP's opening has been blocked by complaints that it poses a danger to nearby Carlsbad Caverns National Park.

Another site identified for underground storage for high-level waste is at Yucca Mountain, Nevada. This location is controversial, in part because local citizens fear that contamination from the underground site could damage the nearby gambling metropolis, Las Vegas. In 1997, Congress directed DOE to complete a "viability assessment" of Yucca Mountain.

DOE also manages 3.3 million cubic meters of low-level waste, which generally does not contain hazardous materials. Most of this material eventually is buried in shallow trenches on DOE land. Currently, disposal is taking place at six sites-Hanford; the Nevada Test Site, near Las Vegas, and the national laboratories in Idaho, Savannah River, Los Alamos, New Mexico, and Oak Ridge, Tennessee. In the past, low-level waste was buried at eight other sites.

Before disposal, low-level waste is treated to stabilize it or to reduce its volume. The waste then is stored until burial onsite or transportation to another DOE site for disposal. Nineteen sites involved in nuclear weapons production now store low-level waste, typically in metal drums or plywood boxes.

Another 32 million cubic meters of nuclear waste, called "byproduct material," consist of tailings left over after the extraction or concentration of uranium or thorium from ore.

These residues still contain much of their original radioactivity. They can emit radioactive radon gas into the environment. In enclosed spaces, this gas can be inhaled and cause cell damage. The tailings also contain low concentrations of toxic heavy metals, such as chromium, lead, molybdenum and vanadium.

Tailings typically are mixed with water to form a slurry and placed in a large pond. There, the liquid is allowed to evaporate or filter out of the pond. The remaining dry tailings, which contain 85 percent of the original radioactivity, are removed from the pond and stored in huge, aboveground piles.

Eventually, these unsightly, radioactive piles are removed. The tailings are collected and stabilized in large, above-grade disposal cells, which are capped to prevent further dispersal of hazardous material. At last count, 82 percent of this byproduct material had been stabilized, and the remainder is scheduled to do so in the next few years.

Contaminated Soil and Water
In the course of decades, the soil and water in the vicinity of nuclear weapons production sites have been contaminated. Sometimes, this damaged material-known as "contaminated environmental media"-resulted from atmospheric fallout from nuclear weapons tests. Other times, waste streams were discharged into the environment, sometimes accidentally and without prior treatment. Sometimes, tanks, drums, and landfills leaked waste into adjacent soil and water.

The department is trying to reduce contamination through treatment, removal from soil and water or containment in places where the hazardous material can do little harm.

In some locations, the water and soil cannot be returned to original conditions. If contaminant concentrations are low and regulators approve, DOE often decides not to treat the polluted soil and water at such sites. Instead, protection is provided by monitoring the contamination and, as much as possible, limiting human exposure.

Faced by this contamination problem and the virtual end of nuclear weapons production, the department has decided to close 5,000 of its facilities-one quarter of the total. Sites identified as surplus are being stabilized to reduce safety risks and maintenance costs. Then, when financially and technically possible, they are decontaminated and decommissioned.

Decommissioning includes removal of contaminated building materials, residual waste, waste treatment, complete destruction or entombment in place.

DOE also finds itself with a wide variety of nuclear and nonnuclear weapon-making material that it no longer needs. A 1995 inventory turned up more than 400 million kilograms of such material at 44 sites in 19 states.

The nuclear material includes natural and enriched uranium, depleted uranium, plutonium, spent nuclear material, and lithium. In the nonnuclear stockpiles are lead, sodium, chemicals, nuclear weapons components, scrap metal, machinery, hand tools, and spare parts.

Some of the materials are valuable and are being sold. Others pose a threat to human health or the environment. Still others, such as plutonium are used in nuclear weapons production and can never be released into the public domain.

Transitions for Workers
To ease the impact on displaced workers, the department has set up a Worker and Community Transition program to draw up plans for each site. The plans include such strategies as incentive programs for both voluntary and involuntary separation, outplacement assistance, and educational assistance to help workers make the transition to new jobs. Some workers are eligible for preferential hiring and severance pay. Communities that are homes to significant numbers of displaced workers are offered economic development assistance to minimize distress to the local area.

These activities have resulted in the amicable separation of more than 30,000 contractor employees via early retirement and other voluntary programs, according to a congressionally mandated report by Booz Allen and Hamilton, Inc. Friendly separations reduce legal challenges and incidences of workplace violence, the report said. More than 22,000 workers participating in the transition program either retained their jobs or found new ones., the report noted.

Paramount in the cleanup drive, DOE officials say, is the need for safety both for workers and the environment. Last year for the first time, the department adopted a "zero tolerance" policy for serious accidents-those that result in life-threatening injuries or major environmental contamination. Frederico Pena, energy secretary at the time, said that the department could no longer accept anything more than zero serious accidents in its nuclear program.

"At stake are nothing less than the lives and livelihood of our workers and neighbors and a healthy environment to leave to our children," he said. Under the zero-tolerance policy, officials said, any serious accident will result in a personal view by the energy secretary. DOE contracts now are written to require excellent safety practices. Poor safety practices could put entire performance-based fees at risk, officials said. Putting the new policy quickly into effect, DOE announced a flurry of enforcement actions during the past year for violations of its safety rules. Some examples:

Fluor Daniel Hanford Inc., operator of the Hanford Site in Washington state was cited for safety lapses associated with an explosion that caused significant damage and released radioactivity to the facility.

The University of California, operator of the Lawrence Livermore National Laboratory, was ordered to take corrective actions for safety violations that resulted in a worker inhaling radioactive material.

The Kaiser-Hill Company-integrating contractor at DOE's Rocky Flats Environmental Technology Site, near Golden, Colorado-agreed to pay $100,000 in order to resolve several potential safety violations involving workers receiving doses of radiation.

The Idaho laboratory was cited for safety deficiencies in its Experimental Test Reactor Building that resulted in an accidental release of toxic carbon dioxide, causing one death and several life-threatening injuries. In order to minimize risk to human health and the environment, the department is pushing to make rapid progress on the cleanup over the next few years. In fact, a recent report by DOE's Office of Environmental Management says the department is "moving aggressively" to close 90 percent of the 353 projects identified for cleanup before 2006.

This effort, however, "is expensive, technologically complex, closely regulated and relatively unique in the world," warns the report. "Much of what needs to be done has never been done before, or even attempted."

Technological Solutions
To solve the technological problems surrounding the cleanup, the department is turning to universities, DOE national laboratories and other research institutions-many of whom were involved in the original program to build nuclear weapons.

"These institutions understand the problems that we're facing," explains a DOE official, "so naturally, they're among the first places we look for help."

In October, for example, a total of 24 universities, seven national laboratories, and six other institutions received $30 million for 33 new research projects.

Pacific Northwest National Laboratory, in Richland, Washington, will lead or collaborate on 13 of these projects, pertaining to the nearby Hanford Site. Eleven of Pacific's projects will address specific issues related to cleanup of high-level radioactive tank waste and contamination of soil between the ground surface and the water table. Said Undersecretary of Energy Ernest Moniz:

"These projects are targeted at some of our most difficult problems-the millions of gallons of high-level radioactive waste stored in tank farms and the thousands of contaminated buildings that must be torn down."

The Lawrence Berkeley National Laboratory, in Berkley, California, will help develop technology for improved gamma ray imaging cameras to map contaminated structures without intruding or doing damage.

Brookhaven National Laboratory, in Brookhaven, New York, will investigate use of a form of citric acid to remove radionuclides from contaminated metal surfaces.

The University of Pittsburgh, in Pennsylvania, will develop simple, inexpensive chemical testing materials that can be used as visual color test strips to report selectively on the identity and concentration of pollutants.

The University of North Texas, near Dallas, will team up with Tennessee's Oak Ridge National Laboratory, to explore new approaches to separate sodium salts from highly alkaline and radioactive tank waste. Sodium salts make up as much as half of tank wastes, complicating treatment of the radioactive material.

To give weapons scientists faster and more powerful tools for analysis of cleanup problems, DOE is developing five generations of high-performance computers. In November, the department and Silicon Graphics, Inc., unveiled the world's fastest computer, code named "Blue Mountain."

Located at the Los Alamos laboratory, Blue Mountain is organized into 48 shared-memory multi-processors (SMPs), which behave like a single computer. The SMPs can communicate with each other at world-record sustained speeds in excess of 650 gigabits a second.

During 1999 alone, Blue Mountain is expected to execute 80 million trillion operations relating to the nuclear stockpile. This is roughly 10 times more computing than all of the calculations executed in support of the stockpile from the Manhattan Project during World War II through the end of underground testing in 1992.

Development of such high-speed computing ability offers the prospect of "significant progress," DOE officials say. But they warn that nuclear cleanup will remain one of the world's most complex problems for decades to come. ND

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