The nuclear mess at Hanford

Hanford is one of 17 large nuclear weapons plants in the country. Most of the approximately 75 tons of plutonium made there went to the stockpile of nuclear warheads during the Cold War. It also fueled the bomb dropped on Nagasaki in 1945. A lot of the deadly material is still at Hanford, contaminating mothballed factories, the soil and groundwater, and seeping into the Columbia River. In 1989, the U.S. Department of Energy agreed to clean it up. More than 18,000 people work at Hanford, most of them for private companies hired by the government to manage and clean up the wastes. Cost of the work this year: about $2 billion. THE NUMBERING SYSTEM The Hanford numbering system was developed by E.I. duPont de Nemours, Inc., during the 1940s. The lower numbers (100 area) were assigned when the process began and numbers increased toward the city of Richland (700 area). THE 100 AREA: Nine Department of Energy plutonium production reactors were built here, along the Columbia River. Plutonium for the “Fat Man” bomb, dropped on Nagasaki, was produced here. THE 200 EAST AND WEST AREAS: Spent fuel processing and disposal of nuclear waste occurred here. The 177 waste tanks are in these areas. THE 300 AREA: Containes fuel fabrication facilities to support the 100 area, along with other research facilities and labs. THE 400 AREA: The newest part of the site contains the Fast Flux Test Facility, a sodium-cooled reactor that is being shutdown. THE 600 AREA: Covers the remaining undesignated areas of Hanford. THE WAHLUKE SLOPE: Located across the Columbia River from the 100 area. The slope, along with the Arid Lands Ecology Reserve, will soon be released for other uses - reducing the reservation’s size by about 40 percent. THE 1100 AREA: General support facilities, such as warehouses, bus parking and purchasing, are located here. DESERT SOILS Dangerous liquid wastes were dumped into Hanford’s desert soils for more than 40 years. Workers poured the wastes in cribs, French drains, reverse wells and other crude disposal devices. That is outlawed today. So much diluted wastewater went into ponds that the groundwater in some places rose 75 feet. In all, about 440 billion gallons of liquids soaked into the ground. THE COLUMBIA RIVER THREAT In 1986, the U.S. Geological Survey estimated that ground water probably moves the 7 to 9 miles from the main dumping grounds to the Columbia River in 10 to 20 years. But it but could travel the distance in as little as six years under some conditions. THE PROBLEMS Scientists used to think pouring radioactive and chemical bomb wastes into the ground was OK. They felt the most toxic material would sink to the bottoms of the pits and no deeper, thus not contaminating groundwater. In some cases, the approach worked. In others, it failed. Among the worst mistakes: 1945-47, about 11 million gallons of liquid radioactive waste were pumped down two deep injection wells directly into the aquifer. The liquid contained about 16 pounds of plutonium. The wells were closed when plutonium was found miles away, but still on the Hanford site. 1946-66, more than 120 million gallons of highly radioactive tank wastes were poured into cribs - essentially covered trenches - in the 200 East area because Hanford was running out of tank space. No tank wastes have been dumped intentionally to the ground since 1966. Radiation in these wastes can move quickly toward the Columbia River because it is mixed with chemicals, including tons of sodium, nitrates, sulfates, cyanide and fluorides. THE SOLUTIONS There is no overall plan to clean up all the contaminated soil. It would be too expensive to dig it all up, and the radioactive dirt would have to be stored . Hanford managers are pumping non-radioactive carbon tetrachloride from the ground. In the cribs where the tank wastes were dumped, radioactive strontium 90 and cesium 137 and toxic cyanide are in the ground within nine feet of the crib bottoms. Hanford managers say the toxics will probably stay there. But wastes traveled into the groundwater when first dumped. In a five-acre test site surrounding the cribs, engineers are developing an asphalt barrier to last 1,000 years. The idea is to keep rain and other water away from the waste so it won’t move any further. Eventually, large “warning” markers will be placed over the site, where it will take at least 600 years for the strontium 90 to decay. Hanford workers also plan to remove some soil and debris from old waste dumps, especially those near the Columbia River, and move it to a proposed landfill on the site. The mega-landfill could eventually cover 1.6 square miles. GROUNDWATER: The public considers cleaning up Hanford’s 200 square miles of contaminated groundwater a top priority. Groundwater from Hanford flows into the Columbia River at a rate of 10 to 50 cubic feet per second. Some is contaminated with radiation and chemicals. hown underground river of radioactive tritium flows into the Columbia north of the old Hanford townsite (shown above left). A trickle of strontium 90 goes into the river at N Springs near N Reactor (above right). Since 1989, the amount of untreated wastewater intentionally dumped into Hanford’s soils has been cut by over 80 percent. Such discharges are supposed to end by June 1995 under a cleanup agreement. Hanford workers also are working on a barrier at N Reactor to keep more strontium 90 from getting into the river.