Extending some Hanford environmental cleanup deadlines is being proposed because of newly discovered contamination and also to build experience before tackling some challenging central Hanford work.
The Department of Energy and its regulators, the state Department of Ecology and the Environmental Protection Agency, have agreed to the revised deadlines for the Tri-Party Agreement. However, the changes will not be approved until after the public has a chance to comment.
Among changes, the deadline to set a schedule for cleaning up large processing plants in central Hanford would be postponed for a decade. Now, the deadline is March.
However, the Tri-Party Agreement agencies want to see what can be learned from the cleanup of the first processing plant on the list, the U Plant Canyon. It is expected to be the first processing canyon in the nationwide DOE complex to be cleaned up.
Hanford has five processing plants -- sometimes called canyons for their long, narrow, high and windowless interiors -- that were built to chemically process irradiated fuel rods to remove plutonium for the nation's nuclear weapons program.
However, U Plant was never needed for that purposed. I was used to recover uranium from processing waste. It's expected to be the least contaminated.
Extensive work has been done to prepare it for demolition, removing equipment, piping and other contaminated debris. They've been fitted like puzzle pieces inside the 40 cells below U Canyon's deck that were used for chemical processing, and have been grouted in place.
Plans call for the walls to be collapsed and an earthen barrier, or cap, built over the demolished building to keep out water.
That won't be done until after most of the environmental cleanup closer to the Columbia River is completed in 2015. It's scheduled to be completed in 2021.
"The agencies believe it is in the best interest to get the cap on" before other canyons are addressed, said Doug Shoop, deputy project manager for the DOE Hanford Richland Operations Office. "We'll learn from that and get a schedule and plan in place for the rest."
Other processing canyons include B Plant, T Plant, REDOX and PUREX.
The agencies also are proposing the delay because the canyons don't pose an immediate risk to the environment, said Jane Hedges, manager of the Department of Ecology's Nuclear Waste Program.
"They are very robust facilities," and surveillance and maintenance is being conducted, Shoop said.
Other proposed deadline changes are for projects in the area along the Columbia River, where additional contamination has been found since current deadlines were set.
That includes the highly radioactive, concentrated cesium and strontium spill from a hot cell into the soil beneath the 324 Building just north of Richland. The building was supposed to be torn down by September 2015, but that deadline will be extended by three years.
"It's going to be a very challenging project," likely involving robotics, Shoop said.
In a second deadline extension for work near the Columbia River, more time is planned to cocoon the K East Reactor, or put it in temporary storage by tearing it down to little more than its radioactive core, sealing it up and reroofing it. Then it would be left to allow radiation to decay to more manageable levels during 75 years.
However, the reactor's water-filled cooling basin is known to have leaked contaminated water into the soil. It's since been removed, but Hanford officials want to delay cocooning the reactor until more is known about the contaminated soil.
"The potential for additional contamination is the driver," said Dave Einan, an EPA environmental engineer.
However, there also could be a cost savings if the K East and K West reactors are cocooned at the same time, Shoop said.
The K West Reactor cannot be cocooned until radioactive sludge is removed from containers in its cooling basin and the basin is demolished.
Now the K East Reactor is required to be demolished by July 2014, but that would be extended to the K West Reactor deadline of December 2019 under the proposed Tri-Party Agreement changes.
More extensive chromium contamination in soil near some reactors is behind another proposed deadline change. Chromium was added to reactor cooling water to prevent corrosion.
Near C Reactor, chromium-contaminated soil has been dug up down to 85 feet deep. Cleanup decisions there would be delayed for about two years to allow more wells to be drilled to collect information about chromium in the groundwater.
In addition, some deadlines are proposed to be extended after 154 additional soil waste sites were identified near the Columbia River as cleanup has progressed there.
More information is posted at www.hanford.gov on the event calendar under each day of the comment period.
Comments may be submitted starting Monday through Jan. 24 to TPACH@rl.gov or to Tifany Nguyen, Department of Energy Richland Operations Office, P.O. Box 550, A7-75, Richland, WA 99352.