Radioactive contamination is spreading within one of Hanford’s huge processing plants, and the problem could escalate as the plant, unused since the 1960s, continues to deteriorate.
A new report on the Reduction-Oxidation Complex, more commonly called REDOX, recommends that $181 million be spent on interim cleanup and maintenance of the plant. REDOX is not scheduled to be demolished until about 2032, or possibly later because the nearby 222-S Laboratory in central Hanford will be needed to support the Hanford vitrification plant for another 30 to 40 years.
The REDOX plant, one of five large processing plants at Hanford, is deteriorating and radioactive waste within it is spreading.
The main building is huge, measuring 468 feet long, 161 feet wide and 60 feet tall, with additional underground processing area.
Each annual inspection of some parts of the plant from 2012-15 found an escalation in the spread of radioactive contamination, including by precipitation that has leaked through the roof and joints of the concrete building.
Spread of contamination has been observed throughout the buildings and will intensify as the facilities continue to degrade.
DOE report on REDOX
Salt used to neutralize the contaminated processing system after it was shut down in 1967 appears to have corroded through some of the stainless steel process piping, according to an earlier Defense Nuclear Facilities Safety Board staff report.
Plastic bags were taped on one processing line to catch any drips of residual plutonium nitrate in places where leaks were anticipated. Two of the bags hold significant amounts of plutonium nitrate, which will spread if the bags leak, the DOE report said.
Signs of animal intrusion and deteriorating asbestos have been found in inspections of several areas.
REDOX was used from 1952-67 to process about 24,000 tons of irradiated uranium fuel rods to remove plutonium for the nation’s nuclear weapons program and also to recover uranium to reuse in new fuel rods.
The report considered three plans to slow down deterioration and take action to confine contamination and reduce its spread, recommending the most extensive of the three alternatives. The plans range in cost from $148 million to $181 million.
Actions would include tearing down the plant’s radioactively contaminated Nitric Acid and Iodine Recovery Building and the main plant’s attached annexes. Two underground, single-shell tanks used to hold up to 24,000 gallons each of hexone also would be removed, if possible. Hexone was used in the process to extract plutonium from fuel rods.
Elsewhere in the plant, steps would be taken to reduce current hazards, which also could help prepare for the eventual demolition of the plant. Waste could be stabilized by isolating it or covering it with a fixative. Piping out of the plant could be plugged, fluids could be drained from piping and equipment, and some equipment could be removed.
Modifications to the plant’s ventilation system would be needed for some of the work.
The actions also target maintaining a skilled workforce at the Hanford Site that is experienced in contaminated deactivation and decommissioning work, which will be needed when major funding becomes available in the future.
DOE report on REDOX
Doing the proposed work would help retain workers experienced in decommissioning nuclear facilities at Hanford. They will be needed as more federal money becomes available for central Hanford environmental cleanup in the future, the report said.
DOE will consider public comments before a decision is made to proceed with work. Work would be done over the next several years as money is available and as the need for the work at REDOX is balanced against other Hanford cleanup priorities.