The Department of Energy has amended its record of decision on Hanford's K East Reactor to allow it to be either torn down or cocooned as most other reactors have been.
No decision on disposition of the reactor has been made, said Geoff Tyree, DOE spokesman.
But the amendment to the 1993 decision -- which called for the reactor to be cocooned -- is one more step toward allowing the reactor to be torn down in the next few years if DOE and its regulators decide that would be best.
The public will be allowed input on the decision, which DOE expects to make in September, Tyree said. DOE also plans an engineering evaluation and cost analysis.
DOE has cocooned five of the nine reactors along the Columbia River at Hanford that produced plutonium for the nation's nuclear weapons program.
The process includes tearing the reactors down to little more than their radioactive core, sealing up openings and reroofing the remaining structure. The reactors then are left for 75 years to allow some of their radiation to decay.
The 1993 plan then calls for the 8,000-ton graphite cores to be hauled to central Hanford on a crawler like the one used to move space shuttles.
However, DOE instead is considering demolishing the K East Reactor, partly because it has significant radioisotope contamination of soil adjacent to and possibly beneath it. The contamination is left from past leaks from its cooling basin, which was used to store irradiated fuel.
Removal of all the contaminated soil cannot be completed while the reactor stands, and excavating too close to the reactor would make it unstable in case of an earthquake. The reactor is about 400 yards from the Columbia River.
If demolition is done now, the reactor could be disposed of while Hanford has a landfill, the Environmental Restoration Disposal Facility, open to receive low-level radioactive waste. In 75 years, a work force would need to be found or trained to do the work and the landfill reopened.
CH2M Hill Plateau Remediation Co. recently drilled into the reactor's core to take four core samples for analysis. It's waiting for results, said CH2M Hill spokeswoman Dee Millikin.
The contractor also continues to remove asbestos from the reactor, which needs to be done whether the reactor is cocooned or razed.
Since the decision was made to cocoon Hanford reactors in 1993, advances have been made in technology and worker safety practices, according to a DOE analysis. In addition, DOE has experience from work to dismantle the core of a lower-power reactor at Brookhaven National Laboratory in New York, the analysis said.
DOE has cocooned the D, DR, H, F and C reactors. Remaining are the K East, K West and N reactors. B Reactor is expected to be saved as a museum.