The federal government issued its first final cleanup decision for one of Hanford’s reactors without incorporating changes recommended by the Hanford Advisory Board and environmental groups.
The Department of Energy and the Environmental Protection Agency adopted a plan for the area around Hanford’s former F Reactor that would leave radioactive waste deep underground in one place to decay over 264 years.
Groundwater contamination would be left to dissipate over 150 years.
“(The Department of Energy) is choosing to ignore overwhelming, common-sense input from citizens throughout the Pacific Northwest who want to see a proactive approach to reducing pollution that reaches the Columbia River from the Hanford site and the F Reactor area,” Dan Serres, conservation director for Columbia Riverkeeper, said in a statement.
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Most of the environmental cleanup of the area around F Reactor already has been completed under interim decisions. The final decision focuses on what remaining work will be done before cleanup is declared completed.
The Hanford Advisory Board has closely followed plans, aware that the decision for the area around F Reactor could set the stage for decisions on cleanup around the other eight plutonium production reactors that line the Columbia River at Hanford.
The board recommended that DOE and EPA take action to significantly reduce the time for cleanup goals to be reached after DOE released its proposed plan. The final decision largely adopted that proposal.
The board also expressed concern about DOE’s ability to restrict use of the land to prevent intrusion into areas with contamination far into the future.
The adopted decision requires digging up contamination in 91 places, but leaving radiological contamination deeper than 15 feet below ground in 15 places.
Excavation restrictions to prevent contact with the contaminated soil would need to be in place, with limits at different sites lasting from the year 2033 to 2278. In one place, irrigation would need to be prohibited to prevent water from carrying contamination down to groundwater.
The agencies considered active treatment of already contaminated groundwater, including pumping up the water and cleaning it before reinjecting it into the ground, but instead settled on letting the contamination gradually dissipate.
Natural processes such as biodegradation, dispersion, dilution and radioactive decay would reduce contamination over 150 years to drinking water standards, the decision document said.
The cost of actively treating the groundwater would be $177 million to $194 million, while letting it dissipate while monitoring it with wells and restricting its use would cost $36 million, according to the decision document.
“We are disappointed that Energy has not opted to use available technologies for a thorough cleanup,” Emily Bays of Hanford Challenge said in a statement.
DOE said in the document and at a recent Hanford Advisory Board committee meeting that it had good reasons for the choices made.
The groundwater contaminant that will take the longest to dissipate, 150 years, is radioactive strontium. However, a “pump and treat” plant for much higher levels of strontium near Hanford’s N Reactor did little to reduce contamination there.
A pump-and-treat system could reduce other contaminants near F Reactor, including nitrates and hexavalent chromium. But the groundwater would still be contaminated with strontium for 150 years, preventing its use, the decision document said.
Near N Reactor, workers add chemicals to the ground to form calcium phosphate to bind the strontium in place and prevent it from reaching water.
But the decision document for the area around F Reactor concluded that the strontium contamination near F Reactor is bound to the soil in a specific area and is not migrating. Adding the underground chemical barrier would not reduce the 150 years needed for it to decay.
Leaving contaminated soil deeper than 15 feet should not be a concern for most uses of the land, according to DOE. That would allow a residential basement to be dug, for example, without excavation reaching contaminated soil.
The federal government would be responsible for ensuring that contaminated water is not used and that digging of wells or other deep excavation does not expose contaminated soil over 100-plus years.
“We realize there are always going to be concerns about how long these can be maintained and how reliably,” said Greg Sinton, the DOE project lead for the decision document at the advisory board committee meeting.
However, reviews will be done at least every five years, as required by federal law, he said. That should keep attention on the remaining contamination and not allow it to be forgotten, he said. If the reviews find that contamination is not dissipating as expected under the decision just made, new cleanup plans could be adopted.
The Hanford Advisory Board made recommendations to DOE and EPA on the pending decision for cleanup in the area of F Reactor in June 2013 and September of this year and could choose to make a formal comment again now that the decision has been made.