Source: EM Update | Vol. 11, Issue 22; Contributor: Mike Butler | June 11, 2019


Workers conduct a test before removing crust and scale from the inside of pipes in the Alpha-4 building.

Crews recently recovered more than a ton of mercury from an aging facility at the Y-12 National Security Complex, marking another EM project that has prevented a release of the element into the environment.

EM teams successfully removed the mercury from tanks in the Column Exchange (COLEX) equipment on the east side of Y-12’s Alpha-4 building. Last year, cleanup contractor UCOR collected nearly 3.5 tons of mercury from COLEX equipment on the building’s west side. The latest effort boosted EM’s total mercury removal in the facility to more than 4.6 tons.

“Our skilled workforce safely inspected, cleaned, and retrieved mercury from old pipes and equipment,” said Brian Henry, Y-12 portfolio federal project director for DOE’s Oak Ridge Office of EM. “This project prevents an environmental release, and it takes us a step closer to prepare Alpha-4 for its eventual demolition.”

Alpha-4 is a four-story, 500,000-square-foot facility used for uranium separation from 1944 to 1945. Workers finished installing the COLEX equipment in 1955 for lithium separation, a process requiring large amounts of mercury. A significant amount of mercury was lost into the equipment, buildings, and surrounding soils during that time, and its cleanup is one of EM’s top priorities.

While employees drained the majority of materials from the equipment when operations ended in the 1960s, they did not clean all of the systems and components. Recoverable amounts of mercury remained in the aging lines and equipment, which have rusted and deteriorated over the decades.

EM and UCOR conducted the recent six-month project in three phases. During each test, mercury was recovered from the piping, consolidated, and stored in the facility.

In the first phase, staff used an optical device to inspect and catalogue residual materials inside piping. The second phase involved testing decontamination methods to remove crust and residual materials from inside the process piping. The knowledge learned through that effort will play a pivotal role in removing the building’s remaining COLEX equipment and piping.

In the final phase, workers recovered any liquid mercury that remained in the piping and equipment. Additionally, employees drained and inspected 22 tanks to determine if any additional deactivation is needed prior to demolition.

The COLEX mercury removal project is part of a broader initiative to address the significant amount of mercury lost to equipment, buildings, and surrounding soils during Y-12’s historical operations.

The next big step in that larger effort begins this summer with construction of the Mercury Treatment Facility. It is a vital piece of infrastructure that will limit and control potential mercury releases as crews take down massive buildings and address soils in the mercury-contaminated area on the west end of Y-12. When operational, the facility will treat up to 3,000 gallons of water per minute and include a 2-million-gallon storage tank to collect stormwater.