contents

Six Decades of actinide production and cleanup

This editorial was contributed by Dr. Ned Wogman, director of Science and Technology for National Security and director of Homeland Security at Pacific Northwest National Laboratory.

The first non-Indian settlers arrived in the Columbia River basin in what is now southcentral Washington state in the mid-1800s. They found a dry, almost treeless desert; the major rivers through the area-the Columbia, Snake, and Yakima-had little effect on the sagebrush-dominated landscape.

Irrigation projects built in the early 1900s allowed a small number of farmers to scratch out a living. Richland, Hanford, and White Bluffs, the farming towns along the river, weathered economic ups and downs as the area was affected by drought, the Depression, and the construction of Grand Coulee Dam. World War II brought an end to two of the towns and radically changed the third.

World War II and the Manhattan Project

Research with uranium-235 demonstrated the feasibility of a uranium atomic bomb, but that isotope was rare and difficult to separate. In March 1942, Glenn Seaborg's group at the University of California produced the first plutonium-239. The U.S. Army Corps of Engineers was given the responsiblity of developing both uranium and plutonium weapons. In June 1942, the Manhattan Engineering District was formed to accomplish the task.

Plutonium production required a nuclear reactor to transmute uranium and chemical separation plants to extract the plutonium and purify it. In addition to the scientific challenges, the Manhattan Project had to deal with the demands of wartime secrecy, chronic shortages, and the poorly understood dangers of this radioactive element. Site selection criteria called for a large, undeveloped, remote, sparsely populated area with a supply of clean water and electricity.

The area along the Columbia River was selected. The towns of White Bluffs and Hanford, along with the surrounding farms, were confiscated. Richland was turned into a government town. Groundbreaking at the site took place in March 1943.

The towns of White Bluff and Hanford were evacuated in 1943 to build plutonium production facilities. Because plutonium had never been produced on a large scale and there was the potential for accidents, the production facilities had to be located away from the populated East Coast and other Manhattan Project sites. Between 1,200 and 1,500 people were evicted in a one-month period. The high school in Hanford is one of the few structures that remains from the old towns. These two photos show the high school as it appeared in the early 1950s (top) and today (bottom).

Thirty months later the site had three nuclear reactors, three processing canyons, sixty-four underground storage tanks for high-level waste, 385 miles of road, 158 miles of railroad, thirty miles of electrical transmission lines, and hundreds of miles of fence. Richland changed from a farming town of 500 to a government town of 17,500‹and another 50,000 workers were housed just north of Richland.

The first chemical processing plant was's first large-scale plutonium separations facility. The plant contained twenty-two sections with two cells in each section.

Once in operation, high levels of radioactivity would preclude personal access to the cells, so the separations equipment was designed for remote operation. B-Plant was similarly constructed but was sixty-five feet shorter, as it lacked the head-end testing cell.

In less than two years and under a cloud of secrecy, the reactors and facilities necessary to produce the plutonium used in nuclear weapons to end World War II were built at the Hanford Site. By October 1944, the first reprocessing facility, T-Plant (in the background), began operating. U-Plant (in the foreground) was under construction during the mid-1940s.

Both plants used the bismuth phosphate process. In this process, the cladding jackets were first dissolved from the fuel rod. Then a series of precipitation, centrifugation, and redissolution steps purified the plutonium. The valence of the plutonium was manipulated to keep it in solution (+4) or to precipitate it (+6).

The solution coming out of T- and B-Plants went through a bulk reduction process, a batch process that reduced 330-gallon batches to eight gallons. The final stage was isolation. Hexavalent plutonium was precipitated as plutonium peroxi

Originally the bismuth phosphate process took twenty-six hours to extract 250 grams of plutonium from one ton of irradiated fuel. By 1955, process improvements reduced the cycle time to four-and-a-half hours.

The plutonium nitrate paste was shipped to Los Alamos, N.M., for conversion to metallic plutonium. The first shipment of plutonium left Hanford on Feb. 2, 1945, and, after traveling by way of Portland and Los Angeles, arrived in Los Alamos on Feb. 3, starting a long association between Los Alamos and Hanford.

The first shipments culminated in the construction of the first nuclear bomb, which was detonated on July 16, 1945, at the Trinity Site near Alamogordo, N.M. On Aug. 9, 1945, a bomb containing Hanford plutonium was detonated over Nagasaki, Japan. Five days later, Japan surrendered.

The future of the Hanford Site was thrown into uncertainty. By December 1946, site employment had dropped from 10,000 to 5,000. The Manhattan Project assumed a caretaker role, and power was reduced on the operating reactors.

A steel girder is lowered by a crane to the floor as construction begins on the inner wall of a 1.1-million-gallon double-shell tank.

The Cold War

The postwar offer by President Truman to transition control of nuclear weapons and energy to the United Nations was vetoed by the USSR, which was pursuing its own nuclear weapons program. In 1947, nuclear weapons production became a priority. In March 1947, President Truman "declared" the Cold War.

Two new reactors were brought online at Hanford in 1949 and 1950, along with a new separations plant, Z-Plant, or the Plutonium Finishing Plant. Up to that time, the separations process at Hanford produced a wet plutonium nitrate paste that was shipped to Los Alamos for final extraction of plutonium metal. At Z-Plant, oxalate, oxide, and fluoride processing steps produced "buttons"‹metallic plutonium in disks resembling hockey pucks.

The Cold War produced military and political pressures: the communist takeover of Czechoslovakia, the Berlin Airlift, the Russian A-bomb, Mao's takeover of China, the Rosenberg-Fuchs-Greenglass-Hiss spy cases, NATO, McCarthyism, and the Warsaw Pact.

Hanford responded with new facilities. The REDOX plant was designed beginning in 1947, constructed beginning in 1949, and went operational in 1952. The process used methyl isobutyl ketone and aluminum nitrate in the first continuous processing plutonium extraction operation.

The plant included a 132-foot-tall silo to house packed columns of ion-exchange material to purify the plutonium and remove fission products. The REDOX plant started processing 3.125 metric tons of irradiated fuel per day; by 1958 it was processing eleven to twelve tons per day.

The N-Reactor, a plutonium production reactor located on the Hanford Site, operated from 1963 to 1987. The reactor¹s main mission was to produce weapons-grade plutonium; however, the reactor could also produce steam to generate electricity. The long building on the left is the power-generating plant.

U-Plant, which had been a training facility for T- and B-Plants, was retrofitted to use tri-butyl phosphate and saturated kerosene to extract uranium from waste solutions; most of the uranium supply in the United States was in Hanford's waste tanks. Ferrocyanide was added to waste streams to precipitate cesium-137. Two more reactors were built, twenty-one new single-shell underground storage tanks were built, and the PUREX plant came online.

PUREX, the plutonium-uranium extraction plant, came about from the realization that the REDOX process used dangerous explosive chemicals, lacked the capacity to meet the perceived need as the Korean War escalated, and was expensive because the aluminum nitrate could not be recycled.

A study group was formed in 1951 to develop a process to address those issues and handle 200 metric tons of irradiated fuel per month, increasing to 400 metric tons when the large KE and KW reactors came on line. The 1,000-foot-long building was completed in 1955; hot start-up was in January 1956.

The unique feature of PUREX was pulsecolumns to put organic and water solvents into contact for chemical separation. These small columns replaced the packed columns of the REDOX process and reduced construction costs. In 1972, PUREX eighteen-month shutdown for planned upgrades to accommodate N-Reactor fuel. The shutdown lasted eleven years.

The Fast Flux Test Facility (FFTF), located north of Richland, is a 400-megawatt thermal, liquid metal (sodium) cooled reactor. The white dome in the background is the containment building that holds the reactor vessel. The building was designed to prevent the release of radioactive material into the atmosphere in case of a severe reactor accident.

Concern about leaking single-shell underground storage tanks resulted in the construction of double-shelled tanks. Major safety upgrades were completed, and two new cells were constructed to convert plutonium nitrate to the safer plutonium oxide powder.

At restart in 1983, the design capacity was 3,000 metric tons per year‹about eight metric tons per day. The average processing, however, was three metric tons per day.

The Plutonium Finishing Plant completes the chemical processing story. It was built to convert plutonium nitrate paste to metallic plutonium because of safety concerns about shipping the paste to Los Alamos.

Construction began in 1948. The plant used Los Alamos chemistry in a series of interconnected gloveboxes. The plutonium nitrate from the separations plant was purified through an oxalate precipitation step. Then hydrogen fluoride gas was forced through the precipitate at high temperature to produce plutonium tetrafluoride powder.

The powder was reduced with calcium, gallium, and small amounts of other substances in a vacuum at high temperature to produce buttons of plutonium metal, similar in size to hockey pucks. The buttons were shaped in the plant for use in weapons until 1965, when shaping was taken over by Rocky Flats outside of Denver, Colo. In 1962, the plant started producing plutonium for use in commercial power reactors as part of an Atomic Energy Commission program.

By 1968, 30 percent of the output was destined for EURATOM reactors and nuclear research. In 1973, operations slowed with the PUREX closure and the plant was upgraded to accept powdered plutonium oxide. The plant restarted in 1984, after the 1983 PUREX restart. Final closure came in June 1989.

President Eisenhower's Atoms for Peace program led Hanford¹s contractor, General Electric, to form the Hanford Laboratories in 1955 to develop plutonium technology for power reactors. In 1963, GE decided to pull out of Hanford to avoid a possible conflict of interest with GE¹s commercial reactor business. Site operations were segmented into reactor operations, chemical separation, fuel production, engineering, and research, and put out for bid. The research segment was renamed Pacific Northwest Laboratory (PNL); Battelle successfully bid on the contract and began operating the Laboratory in 1965.

In the first ten years, Battelle built six laboratory and support buildings in Richland, established a research site in Seattle and a marine laboratory on the Olympic Peninsula, and purchased a research aircraft. Staffing grew from 2,200 to 2,800.

The Lab provided the engineering basis for N-Reactor, a plutonium production reactor that generated commercial power with the steam produced by the reactor coolant.

The Lab also started the Fast Flux Test Facility (FFTF), a liquid metal fast breeder reactor. This program was lost in 1975 in a management disagreement with the Atomic Energy Commission. The program staff that transferred with the program dropped PNL employment to 1,300.

The loss of the FFTF, coupled with uncertainty in the subsequent years as the Atomic Energy Commission was replaced by the Energy Research and Development Administration (ERDA), which was in turn replaced by the Department of Energy (DOE), led to a reevaluation by the Laboratory of its future. Emphasis was shifted from engineering to research and development and a diversification of both mission and customer bases. By 1985, staffing had increased to 2,800.

In April 1986, a nuclear power plant exploded in Chernobyl in the former USSR, now Ukraine. Like the N-Reactor at Hanford, the Chernobyl reactor was a graphite core reactor. Public opinion led to the closure of N-Reactor based on the fear that a similar accident was possible at Hanford. The fall of the Soviet Union in the early 1990s effectively ended nuclear weapons

Tank waste at Hanford varies from crystallized material called saltcake, shown in the top photo inside a single-shell tank, to clear liquids. Saltcake in waste tanks was produced after waste was processed through concentrators that boiled off water, reducing the volume of waste. Slightly concentrated waste was then returned to the tanks where solids crystallized and settled as the solution cooled. In the lower photo, high-pressure water is used to blast simulated saltcake into smaller fragments that can be more easily removed from the single-shell tanks.

Cleanup after the Cold War

Forty years of plutonium production, accomplished under a veil of secrecy, left a legacy of waste at Hanford. Some of the waste was contained in known locations‹underground storage tanks and buried drums. Other waste had been discharged into the ground. Most of the waste contained radioactive isotopes and transuranic elements.

Natural groundwater was in contact with waste plumes and contamination was seeping into the Columbia River. The Hanford Site held two-thirds of all nuclear waste, by volume, in the DOE complex, including 177 underground tanks (sixty-eight suspected or known leakers) holding fifty-three million gallons of waste containing 200 million curies of radioactive materials. Various cleanup scenarios were presented, often based on scant scientific evidence, that would take almost a century to complete and cost hundreds of billions of dollars. Fortunately, the public hysteria died down as new crises du jour came along, and scientists began the analysis necessary to remediate the site.

Characterization of the waste is an ongoing process. Over the years, waste streams from different processes were mixed. Tank wastes sat for decades in environments of caustic chemicals and ionizing radiation. Researchers are determining the current chemical composition of the wastes and the physical stratification of waste components in the tanks.

Underground plumes present other challenges. Their boundaries are diffuse, the wastes exist in low concentrations, and physical and chemical complexes may have been formed with soil particles. Characterization of both tanks and plumes involves physical sampling, records analysis, and computer modeling.

Researchers are also determining strategies to protect future generations from the effects of Hanford wastes.

Vitrification is one method being used to clean up the legacy of waste brought about by forty years of plutonium production at Hanford. In vitrification, heavy metals and radioactive elements are chemically processed into a durable, leach-resistant glass. Vitrification technology has been under development at Pacific Northwest National Laboratory for more than twenty-five years. It has been applied to high-level radioactive waste and municipal solid waste. Waste glass can be formed into useful products such as shingles, rock wool insulation, aggregate, and clean fill.

Vitrification of high-level waste has been selected as the best technology; construction of a vitrification plant is about to start. At the same time, research is continuing to determine the effect of waste types and concentrations on the durability of the glass.

A variety of schemes have been developed for underground plumes. Volatile chemicals can be driven off by heating; organics may be converted by microorganisms; and radioisotopes can be vitrified in place, bonded to soil particles, or physically removed.

This research requires resources and expertise beyond that available at Hanford. A variety of collaborative arrangements with industry, academia, and the national laboratory system bring needed skills and knowledge to bear on Hanford waste remediation.

For example, between August 1988 and February 2002, Pacific Northwest National Laboratory placed 118 contracts for project work with Los Alamos National Laboratory; key words in those contracts include technetium, ferrocyanide explosive, plutonium glass and ceramics, tank waste samples, isotope measurements, plutonium sample analysis, and tank waste remediation. The total value of these contracts is more than $71 million.

In the early 1990s, Pacific Northwest Laboratory became one of the multiprogram laboratories in the DOE's national laboratory system. However, as with all name changes, it took a while for the paperwork to be completed. In 1995, the Laboratory officially added ³National² to its name, becoming Pacific Northwest National Laboratory.

The future

Plutonium production at Hanford contributed to victory in World War II and system bankrupted itself. The combined efforts of researchers at Hanford and those in the current DOE laboratory complex will ensure that the radioactive legacy at Hanford will be dealt with safely and permanently.


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