10-year, 6,000-page study recommends decisions for Hanford cleanup

Massive report advises at least 99% removal of toxic waste from tanks, entomb test facility

By Annette Cary, Tri-City HeraldDecember 6, 2012 

Almost 10 years in the making, a Department of Energy report is complete, and recommends decisions for significant environmental cleanup of the Hanford nuclear reservation for decades to come.

In more than 6,000 pages, the Hanford Final Tank Closure and Waste Management Environmental Impact Statement discusses and lists DOE preferences for cleanup projects that could be adopted as DOE policy under a final decision that could be issued this winter.

Among its preferences is to entomb the Fast Flux Test Facility, empty at least 99 percent of radioactive waste from underground tanks, leave the largely emptied tanks in the ground and continue to ban most radioactive waste from being brought to Hanford until the vitrification plant is fully operational to treat Hanford tank waste.

Most of the major preferences reflect those in the draft study released in October 2009.

However, in those three years DOE has not picked a preference on how to treat all the low activity radioactive waste now held in underground tanks from the past production of plutonium for the nation's nuclear weapons program.

The vitrification plant under construction may be able to treat as little as one-third of the low activity waste in a reasonable time, and 90 percent of the separated waste is expected to be low-activity waste. The plant is expected to treat all the high-level radioactive waste from the underground tanks.

"DOE believes it beneficial to study further the potential cost, safety and environmental performance of supplemental treatment technologies," the final study said.

However, Washington state, DOE's regulator on the project, said it is concerned with DOE's choice not to pick a method now for treating the remainder of the low activity waste.

The study analysis clearly supports expanding the vitrification plant by adding a second Low Activity Waste Facility as the only environmentally protective option for supplemental treatment, the Washington State Department of Ecology wrote in the study.

The state does not support supplemental treatment technologies that do not produce glassified waste, such as steam reforming or cast stone technologies, for low activity waste that will be buried at Hanford after treatment. Glassified high-level radioactive waste would be sent off site to a national repository, once planned to be Yucca Mountain.

The "vague language" in the study brings into question DOE's commitments about when and if all the waste will be removed from 149 leak-prone single-shell tanks and when and if all the tank waste will be treated, the state said. The state pointed out that after DOE invested $85 million in the study, it should have resulted in a preference for a supplemental treatment decision.

DOE previously had opposed sending any of the 56 million gallons of tank waste to the Waste Isolation Pilot Plant in New Mexico, a national repository for transuranic waste, such as plutonium-contaminated waste.

However, DOE now wants to consider the option to send waste from certain tanks to New Mexico, the study said. The state said it had some legal and technical concerns and would need to see a strong justification for designating the waste as transuranic rather than high-level waste.

However, the state, which collaborated on the report, supports most of the document.

"Ecology extensively reviewed the environmental modeling and agrees that the document is technically sound," said Suzanne Dahl, of the state Department of Ecology, in a statement. "It tells us important information about managing waste at Hanford and how to mitigate effects to the environment over time."

The study would continue an agreement not to import off site waste to Hanford -- with some exceptions such as Navy submarine reactor compartments -- until the vitrification plant is operating, which could be 2022.

The study showed that disposal at Hanford of proposed waste from elsewhere significantly would increase effect to groundwater to levels the state is not willing to accept, according to the state.

The preferred plan for the Fast Flux Test Facility, a 400-megawatt research reactor, calls for removing above-grade structures but leaving below-ground structures in place. They would be filled with grout to immobilize remaining radioactive and hazardous constituents.

DOE considered removing single-shell tanks from the ground after 99 percent of waste is removed. But it was concerned about whether that would be technically feasible and could be done without significant exposure of workers to radioactive material.

Instead, it prefers filling the nearly empty underground tanks with grout, removing contaminated soil near the ground's surface and placing a barrier over the ground, according to the study.

DOE is mailing out copies of the environmental study this week to people who requested copies when they attended public meetings or commented on the draft study. It plans to post it at www.hanford.gov, possibly as soon as Friday.

The Environmental Protection Agency will publish a notice of availability in the Federal Register and then DOE will issue a decision in no sooner than 30 days.

-- Annette Cary: 582-1533; acary@tricityherald.com

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