Even as crews work to solve engineering quandaries associated with building the Hanford Waste Treatment and Immobilization Plant project in southeast Washington at the Dept. of Energy’s Hanford Nuclear Waste Site, work continues on tearing out the old facilities.

Built as a main construction site for the country’s nuclear production, the Dept. of Energy must now move 56 million gallons of chemical and radioactive waste stored in underground tanks—the result of more than four decades of plutonium production. The tasks include retrieving, treating and disposing of the waste, the largest and most complex environmental remediate project in the nation. At the same time, crews must remove the buildings originally built to handle the production.

The main processing facility moves closer to final demolition as crews, via contractor CH2M Hill Plateau Remediation Company, finished removing more than 750 feet of contaminated piping, a process that took about three-and-a-half months of working in extremely tight spaces with piece-by-piece removal. Overall, the Plutonium Finishing Plant removal team has extracted about 82 percent of the 7,100 ft. of similar piping in the building, a task required before larger-scale demolition.

“The working conditions were some of the most challenging we have faced, but the crew did an excellent job,” says Gary Hix, CH2M Hill field work supervisor.

Crews must wear protective clothing and breath filtered air to perform the work.

While piping gets removed inside the plant, risk reduction work continues around the site. Part of the process includes building up in an effort to tear down. A concrete floor is under construction to house a mock-up of the saw that will eventually cut through a concrete floor of a highly contaminated former processing cell in the 324 Building. Cutting through the floor is necessary to remove the radioactive soil from beneath the building, which is within sight of the Columbia River.

Testing the mock-up saw in a contamination-free environment, using a floor built to replicate the floor of the processing cell, is meant to reduce risk before deployment into the highly hazardous area.

As crews tear down buildings, Bechtel continues to find ways to build the Waste Treatment and Immobilization Plant, also known as the vit plant since it will turn radioactive waste into vitrified glass for safe long-term storage.

Engineers recently announced solving three technical issues involved with the project, including the potential generation and accumulation of hydrogen in process vessels, potential for nuclear criticality in process vessels and potential for hydrogen accumulation in pipes. A nuclear safety team was formed to resolve each issue.

“I could not be prouder of our WTP technical and nuclear safety teams for their focus and commitment to resolve these technical issues,” says Bill Hamel, the Office of River Protection’s assistant manager for the project.

DOE plans to resolve the remaining technical issues on the project by the end of 2018. 

Follow Tim Newcomb on Twitter at @tdnewcomb