Source: EM Update | Vol. 11, Issue 14; Contributor: Mike Butler | April 9, 2019

Employees with EM cleanup contractor UCOR install fogging equipment on a debris container at the Oak Ridge Site.

EM employees recently began field testing a newly developed fogging fixative and application process aimed at controlling mercury vapors during future deactivation and demolition (D&D) projects at hazardous, mercury-contaminated buildings at the Y-12 National Security Complex.

This is an important research area because mercury cleanup projects present potential workplace hazards through the generation of vapors, especially in warm temperatures. Employees are testing this method on debris from the West Column Exchange (COLEX) equipment removal project, which was completed outside the four-story, 500,000-square-foot Alpha-4 building last fall.

Alpha-4 was originally used for uranium separation from 1944 to 1945. The COLEX equipment was installed in 1955 for a process requiring large amounts of mercury. A significant amount of mercury was lost into the equipment, buildings, and surrounding soils as those operations continued into the 1960s, and its cleanup is one of EM’s top priorities.

Alpha 4 presents an opportunity for EM to test and evaluate various technologies and techniques to safely and effectively D&D buildings contaminated with mercury at Y-12.

The latest demonstration, which began last month, is evaluating a fixative and application process developed at DOE’s Idaho National Laboratory. Testing will help determine if it offers a safe and effective way to suppress mercury vapor and control mercury migration that will occur when major work begins at Y-12’s massive Alpha 4, Alpha 5, and Beta 4 structures.

The fogging demonstration is the first full scale test using both the fixative and the fogging application process. The fogging process is used to blow a fixative material into a container filled with debris with high mercury vapors and monitoring the impact on mercury vapor generation. The fogging has been completed and now EM is monitoring the results.

Previous testing in a laboratory showed fogging reduced mercury vapor generation by a factor of 40. While field application may not reach those figures, even a portion of that result would significantly enhance safety, enable longer working hours, and reduce costs during future mercury-related cleanup work.

“As we transition to address the cleanup scope at Y-12, it is crucial that we identify methods to keep our workforce safe from the hazards presented by mercury and allow us to conduct our projects in an efficient manner to maintain our progress,” said Brian Henry, the Y-12 portfolio federal project director for the Oak Ridge Office of EM.

The COLEX equipment demonstrations take place on the east end of Alpha 4 in conjunction with other mechanical tests to determine more effective methods to remove mercury from the equipment there.

Crews completed the demolition of the COLEX equipment on the west end late last year. During the 18-month project, they recovered nearly 6,500 pounds of mercury from the rusted and structurally degraded equipment, preventing an environmental release. The teams also drained and removed more than 10,000 feet of mercury-contaminated piping, and they cleared away tanks, condensers, heat exchangers, and a 1.6-million-pound mezzanine structure.