By Megan Lowry

In 1943, the town of Hanford in Washington State was selected by the Manhattan Project to be home to the first full-scale plutonium production reactor in the world. Over its next decades on the banks of the Columbia River, the Hanford Nuclear Reservation would produce the plutonium used in the first atomic bombs, and expand to include nine reactors, fuel reprocessing plants, and a major national laboratory.

Today, Hanford is the nation’s most complex nuclear cleanup challenge, with numerous sources of environmental contamination. 56 million gallons of highly radioactive and hazardous chemical waste are stored in 177 tanks on the reservation. While plans have been laid for disposing of the site’s high-activity waste—which contains about 60% of the site’s radioactivity—the plans for low-activity waste at Hanford are less complete. Low-activity waste represents less than 10 percent of the total radioactivity, but by volume it makes up more than 90 percent of the waste at Hanford.

A waste treatment plant to vitrify some of the low-activity waste is under construction, but federal and state officials tasked with deciding the next steps for the site are also reviewing additional technologies for treating and disposing of the remaining supplemental low activity waste—also called SLAW—at Hanford. 

Options for Hanford Waste Disposal

In 2017, Congress directed the U.S. Department of Energy (DOE) to commission a Federally Funded Research and Development Center (FFRDC) to analyze potential technologies for treating and disposing of Hanford’s SLAW. The FFRDC’s analysis is intended to help decision makers assess and weigh their options when selecting SLAW treatment technology.

The FFRDC’s analysis, developed in stages, lays out the estimated cost, timing, benefits, and risks of five options for Hanford’s SLAW: vitrification and disposal at Hanford, grouting and disposal at Hanford, grouting and disposal out-of-state, steam-reforming and disposal at Hanford, and steam reforming and disposal out-of-state.

Vitrification is a commonly used method for treating high-level waste, blending radioactive material with glass-forming materials at high temperatures, then cooling the molten mixture into a solid glass waste form. Grouting involves mixing liquid waste with cement-like materials to form a grout that solidifies in a waste container. Steam-reforming techniques heat waste with clay materials at high temperatures, which converts the solid residue into a granular material similar to powdered detergent. That material is then made into a durable waste form. The purpose of all three technologies is to isolate the radioactivity in a solid form and prevent it from leaching into the environment.

The FFRDC analysis also explores where SLAW could be disposed of after treatment. According to the analysis, SLAW could either be stored in the Integrated Disposal Facility on the Hanford site, or transported out-of-state and stored at the Waste Control Specialists facility near Andrews, Texas.

National Academies Collects Public Comments

The National Academies was tasked in 2017 with reviewing the FFRDC’s work by Congress. In a series of four reports, the National Academies offered recommendations for strengthening the FFRDC's analysis, including that it be revised or followed by a more comprehensive analysis to provide a more substantial basis for decision-making. Congress also directed the National Academies to collect public comments regarding its third review report from local Hanford communities and other stakeholders, and include those public comments in its fourth and final report.

Published this week, the fourth National Academies review says that commenters expressed widespread interest in the potential for out-of-state disposal of Hanford waste. Representatives of tribal nations commented that decision-makers need to consider the entire ecosystem at Hanford and the potential for major climatic changes, massive flooding, and seismic activity, which might adversely affect waste disposal at Hanford.

Many commenters expressed concern about how long-lasting radioactive substances such as iodine-129 and technetium-99 would be treated, given concerns for their potential hazard to drinking water and the river system, especially the nearby Columbia River. Others commented that they believe vitrification would provide more protection for waste disposed at Hanford than the other options presented by the FFRDC.

Next Steps for Hanford

While neither the FFRDC nor the National Academies were tasked with recommending or deciding how supplemental low-activity waste will be treated or disposed of, federal and state officials can draw on their insights as the next steps for Hanford are decided.

“Every aspect of the Hanford cleanup site happens on a huge scale. The volume of the material, the size of the site, the technology we need to employ, the time and cost involved—every factor examined by the FFRDC’s analysis, and by our review of their work, has major consequences for the site, its employees, the local communities, and the nearby environment,” said John Applegate, executive vice president for University Academic Affairs of Indiana University and chair of the committee that wrote the report.

He added, “The FFRDC’s report, our committee’s review, and our observations on comments from the Hanford community provide decision makers with several options to choose from.”

Read the National Academies four-report series reviewing the FFRDC’s analysis here.