PORTLAND, Ore. — A federal proposal for cleaning up the nation’s most contaminated nuclear site says radioactive contaminants from the sprawling Hanford nuclear reservation could threaten the Columbia River for thousands of years.
That prospect ought to force the U.S. Department of Energy, which manages cleanup at the south-central Washington site, to review its long-term clean up plans, said Ken Niles, assistant director of the Oregon Department of Energy.
The federal government is taking public comments through March 19 on its plan for cleaning up storage tanks and managing waste at Hanford, which was created in the 1940s as part of the top-secret Manhattan Project to build the atomic bomb. Cleanup is expected to cost billions of dollars.
The plan to import low-level and midlevel radioactive waste from other sites to Hanford after 2022 poses completely unacceptable risks, Niles said. Washington state officials have also raised concerns about bringing in more waste.
The Columbia River forms the northern and eastern borders of the Hanford site. Downriver, it flows through southern Washington and marks much of the state’s border with Oregon.
The federal government’s environmental impact statement for cleaning up tank waste shows that the risks from some highly radioactive elements have already peaked and should diminish relatively quickly. For all locations at Hanford, the peak radiological risk has already occurred, the report said.
But exposure to contaminants with longer radioactive half lives — such as plutonium, iodine and technetium — is projected to get worse over time in some parts of the site as contamination migrates in groundwater, the report said.
The federal Energy Department says in the statement that its preference is to remove and process 99 percent of the contamination in the tanks, excavate about 15 feet underneath them, then cap the site. It also favors covering contaminated ditches near the tanks instead of excavating them.
But Mary Beth Burandt, a U.S. Energy Department manager, said the agency will likely propose further steps to address public concerns. Such measures could include more treatment, barrier walls to block contaminant flows and limits on long-lived radioactive elements in incoming waste.