Hanford Waste Cleanup

James Chenevey
March 25, 2017

Submitted as coursework for PH241, Stanford University, Winter 2017


Fig. 1: Hanford's N Reactor. (Source: Wikimedia Commons)

Hanford nuclear facility, located in eastern Washington state, produced the plutonium for the "Fat Man" bomb dropped on Nagasaki in 1945 and grew to include nine reactors including the N reactor shown in Fig. 1, during the Cold War years. [1] While supplying this plutonium for the U.S. nuclear program, Hanford also generated billions of gallons of nuclear waste that went on to contaminate the ground and water around the reactors and waste sites. Since 1989, Hanford has been the subject of the largest environmental cleanup in the United States employing about 11,000 people. This cleanup required the collaboration of the Department of Energy (DOE), Environmental Protection Agency (EPA), and Washington state in a deal known as the Tri-Party Agreement that established hundreds of milestones for bringing the 586-square-mile Hanford site into compliance with environmental regulations. [2]

The Damage

The Hanford site accounts for two-third of all high level radioactive waste in the entire country having discharged 450 billion gallons of liquid to soil disposal sites and 56 million gallons of radioactive waste to 177 large underground tanks. [2] This cleanup must address more than 50 gallons of high-level liquid waste in 177 underground tanks, 2,300 gallons of spent fuel, 12 tons of plutonium in various forms, 25 million cubic feet of buried or stored solid waste, and approximately 270 billion gallons of groundwater contaminated above drinking water standards at over 1,700 waste sites and approximately 500 contaminated facilities spanning 586 square miles. [3] These tanks filled with old nuclear waste have to be transferred to new tanks and eventually mixed with glass in a process called vitrification for stability and permanent storage. Technicians must also work to mitigate groundwater contamination before it reaches the Columbia river while old reactors must be demolished and cocooned (encased) in addition to burying tons of waste in huge pits that are lined to prevent leaching into the soil.


Luckily, the commitment of the DOE in conjunction with the EPA and Washington state have allowed for slow but steady progress in the cleanup of the Hanford site. So far, six of nine reactors have been cocooned. With this process, radioactivity in the reactors can be safely decreased over decades making the reactor easier and safer to dismantle in the future. 100% of the site's 2,300 tons of spent fuel, a form of nuclear waste, has been removed from areas around the Columbia river and placed in secure storage. 7.5 million gallons of liquid waste have been removed and transferred from underground single-shell tanks to safer double-shell tanks, completing the stabilization project for the 149 single- shell tanks. 1.25 million gallons of radioactive sludge and saltcake waste have been retrieved from 10 single-shell tanks, reducing the risk to workers and the environment. Finally, 8 billion of the 270 billion gallons of contaminated groundwater have been treated using the five Columbia river facilities that together process 80 million gallons of water per month. [3]


This essential cleanup is a reminder of the long-lasting consequences of hasty nuclear expansion. The hurried waste disposal procedures and inadequate storage containers used throughout WWII and the Cold War have greatly contributed to the size of this project. On the other hand, the collaboration of the Department of Energy, Environmental Protection Agency and Washington state have allowed them to work together to bring the Hanford site into compliance with environmental regulation. After 27 years of cleanup, considerable progress has been made. However, the Hanford site was involved in the production of plutonium for over 40 years and we still have a long way to go.

© James Chenevey. 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.


[1] M. S. Gerber, "History of Hanford Site Defense Production (Brief)," U.S. Department of Energy, HNF-5041-FP, February 2001.

[2] "Hanford Natural Resource Damage Assessment: Injury Assessment Plan ," U.S. Department of Energy, January 2013.

[3] C. W. Connell, "Tracking Cleanup at Hanford," U.S. Department of Energy, HNF-24532-FP, May 2005.