Hanford Site - Cleanup Era

Cleanup Era

On June 25, 1988, the Hanford site was divided into four areas and proposed for inclusion on the National Priorities List. On May 15, 1989, the Washington Department of Ecology, the federal Environmental Protection Agency, and the Department of Energy entered into the Tri-Party Agreement, which provides a legal framework for environmental remediation at Hanford. The agencies are currently engaged in the world's largest environmental cleanup, with many challenges to be resolved in the face of overlapping technical, political, regulatory, and cultural interests. The cleanup effort is focused on three outcomes: restoring the Columbia River corridor for other uses, converting the central plateau to long-term waste treatment and storage, and preparing for the future. The cleanup effort is managed by the Department of Energy under the oversight of the two regulatory agencies. A citizen-led Hanford Advisory Board provides recommendations from community stakeholders, including local and state governments, regional environmental organizations, business interests, and Native American tribes. In recent years, the federal government has spent about $2 billion annually on the Hanford project. About 11,000 workers are on site to consolidate, clean up, and mitigate waste, contaminated buildings, and contaminated soil. Originally scheduled to be complete within thirty years, the cleanup was less than half finished by 2008. Of the four areas that were formally listed as Superfund sites on October 4, 1989, only one has been removed from the list following cleanup.

While major releases of radioactive material ended with the reactor shutdown in the 1970s, parts of the Hanford Site remain heavily contaminated. Many of the most dangerous wastes are contained, but there are concerns about contaminated groundwater headed toward the Columbia River. There are also continued concerns about workers' health and safety.

The most significant challenge at Hanford is stabilizing the 53 million U.S. gallons (204,000 m3) of high-level radioactive waste stored in 177 underground tanks. About a third of these tanks have leaked waste into the soil and groundwater. As of 2008, most of the liquid waste has been transferred to more secure double-shelled tanks; however, 2.8 million U.S. gallons (10,600 m3) of liquid waste, together with 27 million U.S. gallons (100,000 m3) of salt cake and sludge, remains in the single-shelled tanks. That waste was originally scheduled to be removed by 2018. The revised deadline is 2040. Nearby aquifers contain an estimated 270 billion U.S. gallons (1 billion m3) of contaminated groundwater as a result of the leaks. As of 2008, 1 million U.S. gallons (4,000 m3) of highly radioactive waste is traveling through the groundwater toward the Columbia River. This waste is expected to reach the river in 12 to 50 years if cleanup does not proceed on schedule. The site also includes 25 million cubic feet (710,000 m3) of solid radioactive waste.

Under the Tri-Party Agreement, lower-level hazardous wastes are buried in huge lined pits that will be sealed and monitored with sophisticated instruments for many years. Disposal of plutonium and other high-level wastes is a more difficult problem that continues to be a subject of intense debate. As an example, plutonium has a half-life of 24,100 years, and a decay of ten half-lives is required before a sample is considered to be safe. The Department of Energy is currently building a vitrification plant on the Hanford Site. Vitrification is a method designed to combine these dangerous wastes with glass to render them stable. Bechtel, the San Francisco based construction and engineering firm, has been hired to construct the vitrification plant, which is currently estimated to cost approximately $12 billion. Construction began in 2001. After some delays, the plant is now scheduled to be operational in 2019, with vitrification completed in 2047. It was originally scheduled to be operational by 2011, with vitrification completed by 2028.

In May 2007, state and federal officials began closed-door negotiations about the possibility of extending legal cleanup deadlines for waste vitrification in exchange for shifting the focus of the cleanup to urgent priorities, such as groundwater remediation. Those talks stalled in October. In early 2008, a $600 million cut to the Hanford cleanup budget was proposed. Washington state officials expressed concern about the budget cuts, as well as missed deadlines and recent safety lapses at the site, and threatened to file a lawsuit alleging that the Department of Energy is in violation of environmental laws. They appeared to step back from that threat in April after another meeting of federal and state officials resulted in progress toward a tentative agreement.

A sample of purified plutonium was uncovered inside a safe in a waste trench at the site during excavations from 2004 to 2007, and has been dated to approximately the 1940s, making it the second-oldest sample of purified plutonium known to exist. Analyses published in 2009 concluded that the sample originated at Oak Ridge, and was one of several sent to Hanford for optimisation tests of the T-Plant until Hanford could produce its own plutonium. Documents refer to such a sample, belonging to "Watt's group", which was disposed of in its safe when a radiation leak was suspected.