The U.S. Department of Energys Savannah River National Laboratory and its Defense Waste Processing Facility were honored recently for an innovative environmental initiative that reduces waste volumes and eliminates the need for workers to enter a high-radiation area of the waste processing facility.
The development and deployment of a new remote gasket removal and replacement tool earned the team an honorable mention in the annual White House Closing the Circle Awards, which recognize outstanding environmental stewardship at federal civilian and military facilities.
This year, 15 winners and 13 honorable mentions were selected from nearly 200 nominations in the areas of environmental management systems, pollution prevention, recycling, green product purchasing, alternative fuels, electronics stewardship and sustainable buildings. Savannah River Site is one of only two DOE facilities to be recognized in this years awards.
The awards ceremony was held last week at the National Institutes of Health, in Bethesda, MD, to formally recognize the winning programs. A second ceremony will be held locally at SRS this summer to recognize the team members: Greg Lawson, James Gee, Brian Metzger, Darryl Perry, Rickey Jackson, and Leonard Perry (of DWPF) and Dan Krementz, Jeff Coughlin, Bob Milling, and Mike Dalmaso (of SRNL).
The DWPF processes radioactive liquid waste stored at SRS into a stable glass form for long-term disposition. Whenever a gasket failed on one of the pipes or transfer lines in the facility something that happens as often as 40 times in a year the previous response was to decontaminate the connection as much as possible, then remove it and transport it to a special maintenance cell, where personnel wearing air-supplied protective plastic suits to prevent personal contamination would manually replace the gasket and snap ring. DWPF personnel recognized that the development of remote gasket replacement tooling as an alternative to this hands-on gasket replacement procedure would significantly reduce personnel risks, along with the waste and operational costs associated with the routine maintenance of canyon piping and transfer line connectors.
SRNL researchers, who has extensive experience developing and deploying remote tools for use in radioactive environments, were engaged to develop and test the multiple tools needed. They came up with pneumatic tools for removal of the snap ring and spent gasket, as well as a pneumatic tool to simultaneously install the new gasket and snap ring, and a pneumatic snap ring-loading tool that compresses a new snap ring and places it in a groove in the installation tool. All of these tools are located on a custom work table that can be moved around within the processing facility using existing cranes and manipulators. The table has a pneumatic valve station that directs compressed air to the appropriate tool. The entire table system is designed to be operated using manipulators to position and operate the various tools.
Now, instead of four people dressing out in plastic suits and entering a high contamination/airborne area, the task can be performed remotely by two people using the new tool from outside the cell.
This new approach significantly reduces the quantity of materials that in the past were used and disposed of with each replacement items like plastic suits, hoses, hand tools. These items had resulted in about 11 cubic feet of low-level radioactive waste that had to be disposed of with every gasket replaced; obtaining these materials cost about $5,000 per gasket replacement. With this approach, the assembly no longer needs to be decontaminated prior to replacement, a process that had generated approximately 2,000 gallons of contaminated wastewater per gasket.
Overall, the tool development and deployment is resulting in a savings estimated at $220,000 per year.