RICHLAND, Wash. - Michael Stevens has worked his share of demolition projects across the DOE complex.
But the project manager for the EM Office of River Protection ’s (ORP) tank operations contractor was surprised by difficulties experienced when demolishing a small, nondescript metal structure supporting the tank farms.
Within the building was an approximately 4-foot-tall, 1-1/3-foot-wide plywood box filled with lead shot. The lead was used for shielding workers from exposure to radioactivity during certain waste operations and was no longer required.
“This was a unique project. Everybody knew that going into it," said Stevens, who works for Washington River Protection Solutions (WRPS).
Removal of the shield box was the most challenging task in the demolition project. Workers knocked down the building to create a path for future tank waste transfer lines.
“The completion of this project is one of many tasks necessary to prepare for the next single-shell tanks retrieval," said Jeff Rambo, ORP technical program manager for tank retrievals. “This was an important step in advancing the tank waste mission."
ORP took precautions due to the hazards posed by working with lead and other potential contaminants, including beryllium and asbestos.
“The work scope certainly had a lot of challenges to it," said Steven Mata, the field work supervisor for the job. “We took a conservative approach, taking the work one step at a time, and the work planners did a tremendous job of giving us some flexibility to deal with what might come up."
Lessons learned from a mockup exercise indicated the lead shot would flow similar to sand through an hourglass. So, the work crew drilled a small hole near the box bottom, inserted a specially fabricated spout to control flow, and began to drain the lead shot. They inserted a pencil camera in the box to modify their approach and remove the remaining lead when they encountered difficulties.
“The uniqueness of the job made it interesting and challenging," said John Wright, WRPS construction manager. “People were motivated and energized, approaching the job with a ‘safety, compliance, progress’ attitude."
Source: U.S. Dept. of Energy, Office of Environmental Management
