About 150 concrete ecology blocks were hauled by flatbed trucks to central Hanford over the weekend for the next step in stabilizing a partially collapsed tunnel holding radioactively contaminated waste.
Officials plan to lay a flexible plastic covering over the soil berm above the oldest of the two PUREX plant tunnels used for long-term storage of contaminated equipment. The covering will run the entire length of the nearly 360-foot-long tunnel.
The covering will not be laid until plans are finalized and the weather clears. The heavy blocks will hold down the edges of the plastic.
Officials are waiting for a day with little wind. Gusts of up to 21 mph are forecast Tuesday for central Hanford by the National Weather Service.
The covering will be used to keep any radioactively contaminated particles from becoming airborne, which could harm workers and the environment. It also should prevent rain from soaking into the eight feet of soil over the wooden roof of the tunnel, adding to the weight on the roof.
On May 9 workers noticed that a section measuring about 20-by-20-feet had collapsed at the front of the tunnel and an emergency was declared at the nuclear reservation. No airborne radioactive contamination was detected.
The breach has been filled with a mixture of sand and soil. In addition to the plastic covering, DOE is expected to take longer term actions. It could decide to fill the tunnel with grout.
On Monday all remaining employees were told it was safe to return to work.
All but a couple hundred based closest to PUREX returned to work on Thursday. People working at Hanford tank farms closest to PUREX were given alternate work sites on Monday.
Because of the partial tunnel collapse, the Department of Energy and Hanford regulators are postponing a meeting to discuss Hanford environmental cleanup priorities.
The meeting was planned for Wednesday.
Staff have been too busy to prepare materials for the meeting because of the discovery last week of a partial collapse of a Hanford radioactive waste tunnel.
DOE, the Washington State of Ecology and the Environmental Protection Agency traditionally hold a spring meeting to discuss the president’s budget request to Congress for the coming year and the work priorities for the year after that.
Although detailed federal budget information has not been released yet for the next fiscal year at the Hanford nuclear reservation, a meeting still was scheduled and a public comment period planned.
The meeting will be rescheduled, according to the agencies.
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