|Fig. 1: One of the waste tanks at Hanford, during construction. This public-domain image is available through the Freedom of Information Act from the U.S. Department of Energy Hanford Declassification Project. (Courtesy of the U.S. Department of Energy.)|
On the banks of the Columbia River, just upstream of Richland, Washington, is the site of the Hanford nuclear facility. Along with Los Alamos and Oak Ridge, Hanford was a crucial part of the Manhattan Project. Each of these three top-secret sites originally had its own specialty: Los Alamos worked on designing nuclear weapons; Oak Ridge separated uranium-235 from uranium-238; and Hanford manufactured plutonium-239 from uranium-238.  Ultimately, the plutonium produced at Hanford was used in most of the U.S. nuclear arsenal, including the Trinity test device and the Fat Man bomb dropped on Nagasaki.
Hanford was hurriedly built between 1943 and 1945 on expropriated property, eliminating about 1700 km2 of farms and ranches and two small towns in the process.  The first reactor, the 250-megawatt B Reactor, was finished in September 1944 and was immediately put to work, irradiating uranium-238 atoms with neutrons to make plutonium-239. The first 8-km2 separation plant was finished a few months later. There, the plutonium would be chemically extracted from the leftover uranium and other fission products (which were then put into waste tanks). Together, this was the first large-scale plutonium production facility ever built, although the concept had already been tested at the much smaller X-10 Reactor at Oak Ridge. Two more reactors and additional separation plants were built at Hanford before the end of World War II.
Hanford was expanded several times after the end of World War II. Eventually, at the height of the Cold War in 1963, Hanford was home to thousands of buildings, including nine reactors and five separation plants of various designs.  Hanford continued to manufacture plutonium at full capacity through the mid-to-late 1960s, when the U.S. nuclear weapons program slowed down and Hanford's surplus reactors and plants gradually began to be decommissioned and decontaminated.  All told, a total of 67.4 tonnes of plutonium were produced at Hanford over its lifetime. 
|Fig. 2: Radioactive soup inside a Hanford waste tank (1989). Source: Pacific Northwest National Laboratory. (Courtesy of the U.S. Department of Energy.)|
A tremendous amount of nuclear waste was also produced at Hanford. About 245 million liters of highly radioactive liquid, salt cake, and sludge waste from the reactors and separation plants were buried in 177 giant steel tanks, many of which are now leaking into the groundwater.  The actual contents of these tanks are mostly unknown.  In addition, hundreds of billions of liters of lower-level waste were casually dumped in unmarked locations across the site.  By the end of the war in 1989, the last reactor at Hanford was shut down permanently , and all activity since then has been focused on cleaning up this enormous mess.
The Hanford site is currently operated by the U.S. Department of Energy. The high-level tank waste is supposedly going to be immobilized for long-term storage by turning it into glass.  This involves building a very large vitrification plant, which is currently under construction but is still several years away from completion. In the meantime, the waste is being removed from the leaking tanks and stored somewhere else.
The threat of contamination to the Columbia river basin has been studied extensively. In 1998, for instance, a borehole was drilled near one of the waste tanks and the soil was found to be contaminated with 1.8×10-2 Ci/kg of 137Cs at 25 meters below the surface.  For comparison, an injection of just 3.8×10-3 Ci/kg of 137Cs is lethal in dogs within 3 weeks.  To try to mitigate the contamination, berms and gutters have been built on the surface to divert rain and snowmelt away from the contaminated areas, and chemical barriers have been injected underneath the contamination plumes as interim measures while the contaminated groundwater is pumped and treated,  but some of this contamination has already reached the Columbia river and there are doubts over how long the cleanup process will take and how many billions of dollars it will cost. 
In their hurry to produce plutonium for World War II and the Cold War, the engineers and scientists at Hanford also produced environmental contamination that lives on. Some of the radioactive releases were intentional, but a huge amount of contamination was caused by irresponsible waste disposal procedures and inadequate storage containers. The U.S. nuclear industry is more careful with its waste today, but Hanford serves as a reminder that nuclear waste disposal is a problem with long-lasting consequences.
© Eric Eason. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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