Andrew Wheeler, acting head of the U.S. Environmental Protection Agency, on Monday signed a record of decision laying out the final cleanup plan for the 100 D and H Areas along the horn of the Columbia River at the Hanford Site in Washington state.
Cleanup began under interim decisions in the mid-1990s on 7.8 square miles of Department of Energy land near the D and DR reactors and the H Reactor, with the Washington state Department of Ecology acting as lead regulator.
To date, DOE has spent $374 million on remediation of this section of Hanford, with an estimated $200 million of work remaining, primarily for continuing groundwater cleanup. “This land and groundwater cleanup is an important ‘puzzle piece’ in the larger Hanford project,” said Chris Hladick, EPA Region 10 administrator, in a press release. “Since these areas are virtually on the banks of the Columbia River, this work to further reduce toxic and radiological threats to the river is particularly important.”
Remaining work includes cleaning up five of 104 waste sites near the reactors, with most of those locations awaiting final confirmation that completed efforts meet cleanup targets. Remaining waste sites are small, such as some contamination left by wasps on power poles, and are anticipated to be cleaned up within two years. Dozens of buildings have already been torn down and the three reactors cocooned, or placed in interim storage, to allow further radioactive decay before demolition.
Groundwater treatment will continue, with an anticipated upgrade, the EPA said. Two pump-and-treat plants, now removing hexavalent chromium from groundwater, are expected to continue to operate for 12 years. The EPA record of decision also calls for natural attenuation of some remaining strontium 90 contamination. The contamination will be allowed to radioactively decay until drinking water standards are reached within 44 years.
