'Pit Viper' touted for Hanford cleanup

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RICHLAND - Some waste pits at the Hanford nuclear reservation are so hot that they emit in one hour a dose of radiation 100 times higher than workers are allowed to receive in an entire year.

But the pits need to be cleaned and upgraded for transferring radioactive waste from Hanford's underground tank farms to a vitrification plant being designed to turn some of the deadly material into glass logs for long-term storage.

So the Pacific Northwest National Laboratory has designed the "Pit Viper," a versatile, robotic arm and remote video monitoring station that will let workers rehabilitate the pits without being close to them.

Pit work most dangerous

Pit work exposes more workers to more radiation than any other cleanup task at the tank farms, where nearly 54 million gallons of highly radioactive waste are stored in 177 aging and leak-prone tanks.

"Doing this work is extremely hazardous. It is the most dose-intensive task," said Sharon Bailey, Pit Viper project manager for the laboratory.

"We expect this may reduce personnel dose rates by up to 75 percent."

The lab showed off the prototype Pit Viper on Tuesday. The $1 million system will be used at the reservation this summer.

The three-joystick control board and four monitors in the control trailer look deceptively simple.

"That's the idea," said Carl Baker, a senior development engineer for the lab. "We want this to be actually used."

An operator working as far away as 200 feet has views from four cameras showing what the robotic arm is doing. It can lift as much as 200 pounds.

Similar to swimming pools

"We have 600 equipment pits that need to be cleaned up before we can proceed with vitrification," said Paul Kruger, the Department of Energy's associate manager for science and technology.

The pits are, on average, about 8 feet by 10 feet in area and 8 feet deep.

CH2M Hill Hanford Group, which manages the tank farms, would like to have six Pit Vipers, said Rick Raymond, the company's vice president for projects.

Whether the money would be available is unknown.

If funding can be found for the Pit Vipers, the pits can be cleaned out more safely and more efficiently, eventually saving money, Raymond said.

The Bush administration's budget calls for the Energy Department's Office of River Protection - which oversees the tank farms and the glassification project - to receive $814 million for fiscal 2002, when the office needs $1.1 billion to meet its contract obligations.

The vitrification plant is to be up and running in 2007.

Some pits are too contaminated for people to work in; the Pit Viper could solve that. In other pits, radiation-dose rates are sufficiently high that much prep work with shields and other protective devices is required before workers go in, said Don Niebuhr, a field-work supervisor for CH2M Hill.

Even workers standing near some pits can be exposed to annual limits of radiation in a few hours or a few days, he said.

"The site policy is: Don't take any dose without a benefit," he said.