D. Kent Smith is well aware there are no shortcuts when it comes to cleaning up 60 years of radioactive and other wastes at the U.S. Energy Dept.'s Hanford former nuclear-weapons site in Washington state. "We are pumping millions of gallons of the most toxic, dangerous waste on earth, and everyone expects perfection," says the deputy manager of retrieval and closure operations for contractor Washington River Protection Solutions.
As crews work to empty waste remnants from 149 aging underground storage tanks, perfection has required innovation, including the first-ever use of the Mobile Arm Retrieval System (MARS), a redeployable, remotely operable arm designed to reach waste in every tank nook and cranny. In 2011, it was deployed into one tank that still contained 247,000 gallons of hardened sludges and solids.
Each MARS component underwent individual testing before two full-scale mock-ups of the insertion procedure were done. "We spent weeks and months working this in a cold system, and that's where you build confidence," Smith says. "The biggest challenge is keeping everyone motivated and moving forward amid constant scrutiny and criticism."
Adds Sax, "Anywhere else, a mistake will only come back and bite you. If you screw up at Hanford, the consequences are so much higher. Guys like Kent have to be conscious of that."