DOE Says 700,000 Pounds of Mercury Released at Y-12
WC Monitor
7/25/2014
The Department of Energy has released new mercury numbers that give some additional insight into the size and scope of mercury cleanup at the Y-12 National Security Complex. The amount of mercury released during the Cold War lithium operations at Y-12 has been revised over the years, but the consensus number has been that about 1.2 million pounds was lost or otherwise unaccounted for. DOE says that about 20 million pounds of mercury was used at Y-12 during the lithium separation activities that were critical to development of thermonuclear weapons. According to DOE’s Office of Environmental Management, an estimated 700,000 pounds of mercury was released into the environment, either through spills or discharges.
DOE has identified mercury as its top environmental priority in Oak Ridge and promised to accelerate cleanup efforts in coming years. Additional emphasis is projected after the demolition of old uranium-enrichment facilities at the East Tennessee Technology Park has been completed. A new $125 million treatment facility is to be installed at the headwaters of East Fork Poplar Creek, which, according to DOE estimates, has received about 239,000 pounds of mercury discharges over the years. The new facility is supposed to filter about 3,000 gallons of water per minute and remove about 65 percent of the mercury in the storm sewer’s main outfall. The treatment system is scheduled to come online around 2020.
In addition to the mercury that’s already been released into the environment, tons of the toxic metal is still housed in some of the Oak Ridge plant’s old processing facilities. Four buildings totaling 1.8 million square feet—Beta-4, Alpha-2, Alpha-4 and Alpha-5—are slated for demolition, but that’s years away. It will be impossible to fully gauge the mercury contamination in the soil around and under the buildings until the demolition work is done. According to Mike Koentop, the executive officer of the Oak Ridge EM Office, about 20,000 pounds of mercury still resides in Alpha-4. He said the mercury estimates for the other three building were not immediately available, noting they those buildings have not yet been turned over to DOE’s Office of Environmental Management.
It’s anticipated that large volumes of mercury-contaminated soils will have to be treated in the years ahead. Koentop said an estimated 428,000 pounds of mercury is tied up in Y-12 soils or held in underground rock formations.
Some Work Already Performed
Some removal actions have already been conducted at the site. A Recovery Act-funded project removed five mercury storage tanks, which reportedly posed an ongoing hazard to workers and the environment because of escaping vapors. DOE said at least 650 pounds of elemental mercury was removed from the former storage tanks, which had been taken out of service in the 1980s but remained in a scrap yard at Y-12’s west end. The cleanup of the tanks started in 2012 and was completed last year with Recovery Act funds that were saved from some earlier projects. The work was coordinated between URS-CH2M Oak Ridge, the department’s cleanup manager in Oak Ridge, and B&W Y-12, then the managing contractor at Y-12.
Wayne McKinney of UCOR said two of the tanks were not contaminated and were sent to the sanitary landfill at Y-12. The other three were transported to Materials and Energy Corp., a local firm, for removal of the mercury contents and then cut into pieces, he said. “More than 650 pounds of mercury was removed and treated from the three tanks,” McKinney said. “The mercury was disposed at the Nevada National Security Site. A formal report documenting completion of the project was submitted to the Environmental Protection Agency and Tennessee Department of Environment and Conservation.”
Soils were excavated from the storage site and send to vendors for analysis. DOE is hoping to identify methods of stabilizing the mercury within the soil so that the material can be accepted for disposal at the federal’s agency on-site landfill. The agency said local disposal would significantly lower the cost. DOE said the study had identified nine treatment technologies of potential use, but details of those technologies have not been released.
