RICHLAND, Wash. - EM’s Office of River Protection (ORP) and tank farms contractor Washington River Protection Solutions (WRPS) go to great lengths to learn more about the nature and extent of contamination around and beneath Hanford ’s waste storage tanks. Most recently, a project team went about 285 feet.
That was the depth of a vertical hole near Tank A-104 created with a technology known as direct push. It is the first of 10 holes near tanks A-104 and A-105 to be completed during a campaign that will run into 2019. The holes are drilled to varying depths.
The direct push technology involves pushing 4-foot sections of hollow tubes into the ground with a hydraulic hammer. During the current campaign, two holes will be pushed in five locations about 5 feet apart.
The first push is driven to full depth and logged using geophysical instruments. The instruments take radiation and soil moisture readings, and also help determine the sampling locations for the second push. The second push is used to collect soil samples at selected depths.
To collect a sample, the team uses a special drive tip. When the target depth is reached, the tip is released and the drill string driven ahead. Samples are captured inside the drill string, pulled to the surface, and sent for laboratory analysis.
“The information we obtain through the direct push campaign will help support tank retrievals and tank farm closure documentation," said Jan Bovier, ORP tank closure project manager.
Source: U.S. Dept. of Energy, Office of Environmental Management
