Watchdog group Hanford Challenge is objecting to a Department of Energy plan to classify the waste remaining in the Hanford Site’s C Tank Farm as residual waste, or waste incidental to reprocessing (WIR).
The new classification would allow the remaining waste in the C Farm’s 16 tanks to be considered low-level radioactive waste and the tanks closed with the addition of concrete-like grout. The grout-filled tanks would be left permanently in the ground with above-ground caps added to prevent the infiltration of precipitation.
The Energy Department’s draft WIR evaluation, issued in March, concluded the C Farm tanks can be safely closed. Key radionuclides have been removed “to the maximum extent technically and economically practical, that potential doses to the public and human intruder are projected to be well below the doses set forth” for low-level waste, the document says.
The C Tank Farm had 1.8 million gallons of mostly sludge and salt cake when waste retrieval began; about 64,000 gallons remain in the tanks, including waste clinging to the sides of the tanks. The goal is to remove 99 percent of waste on average from all 149 single-shell tanks at Hanford, with about 96 percent of the waste removed from the C Tank Farm. The federal court consent decree governing cleanup at the Washington state facility allowed DOE to consider the waste retrieved from a tank when three technologies had been used to their limit.
Hanford Challenge is calling for DOE to continue to monitor the waste remaining in the C Tank Farm in the hope that better waste retrieval technology will be developed in the next 10 to 20 years. Filling the tanks with grout would preclude emptying more waste if better technology becomes available.
“This will be challenged,” said Tom Carpenter, Hanford Challenge executive director. Grout does not effectively contain radioactive waste, according to the group. Water can infiltrate and the caustic materials in nuclear waste break down the grout quickly. Plutonium would impact the groundwater and Columbia River if the tanks are filled with grout as they are now, Carpenter said.
The Energy Department opened a public comment period on its draft WIR evaluation for closure of the C Tank Farm on June 4 and plans a public meeting to explain the evaluation 9 a.m. to 5 p.m. June 18 at the Richland Public Library. Comments will be accepted at [email protected] through Sept. 7.
