Crews finish injecting engineered grout into Hanford site waste - NBC Right Now/KNDO/KNDU Tri-Cities, Yakima, WA |

Crews finish injecting engineered grout into Hanford site waste storage tunnel

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UPDATE 11/14: 

RICHLAND, WA - Workers have finished stabilizing a waste storage tunnel with engineered grout, after a partial collapse earlier this year. Here is the full statement from the Department of Energy:

"Hanford workers have finished stabilizing a waste storage tunnel with engineered grout, after it partially collapsed earlier this year. Since early October, crews worked mostly at night to place several thousand cubic yards of engineered grout into Tunnel 1 near the Plutonium Uranium Extraction (PUREX) Facility. Grouting reduces the risk of further collapse and increases the protection for workers, the public, and the environment from radiological hazards, while not precluding future remedial actions or final closure decisions.

Department of Energy contractor CH2M HILL Plateau Remediation Company (CH2M) began grouting Oct. 3 and placed the last truckload of grout Nov. 11, without any injuries.

"Stabilizing Tunnel 1 was achieved safely and quickly, due to our skilled workers, solid planning, and extensive coordination," said Doug Shoop, manager, DOE Richland Operations Office. "Our contractor not only completed this work safely, but also ahead of the Department's projected completion timeframe of late December."

"The team did an amazing job," said Ty Blackford, president and chief executive officer, CH2M HILL Plateau Remediation Company. "I couldn't be more proud of the crew, and all those who supported planning and preparations."

Approximately 521 truckloads (4,434 cubic yards) of grout were placed in the tunnel. Cameras in the tunnel ensured the grout flowed the length of the tunnel and around the contaminated equipment inside.  The grout was injected in several lifts, or layers, and each lift was allowed to set up before the next began.  Approximately a foot of space was left between the topmost layer and the ceiling of the tunnel.  

"Now that Tunnel 1 is secure, we can focus on our evaluation and determining the appropriate course of action for stabilizing Tunnel 2," Shoop said.
An integrity analysis completed earlier this year showed nearby Tunnel 2 does not meet current codes for structural integrity, and it may not be able to bear the weight of the soil above the tunnel. Like Tunnel 1, Tunnel 2 contains railcars with contaminated pieces of plutonium processing equipment. Enhanced surveillance is in place to detect any changes to the structural integrity of the 1960s-era waste tunnel. Plans to stabilize Tunnel 2 are under evaluation and should be finalized in the coming weeks.""


RICHLAND, WA  Hanford workers have begun injecting engineered grout into a waste storage tunnel near the Hanford Site's Plutonium Uranium Extraction, or PUREX, Facility, that partially collapsed earlier this year.

The grout is intended to improve the stability of PUREX Tunnel 1 and provide additional radiological protection, while not precluding future cleanup actions or final closure decisions. An estimated 6,000 cubic yards of grout are needed to fill Tunnel 1, requiring about 650 truckloads to fill the nearly 360-foot long tunnel. The grout will be injected into the tunnel primarily during the night to help supply trucks avoid daytime traffic and ensure a steady supply of grout. The work is expected to be completed by the end of this calendar year. 

To place the grout, workers removed some of the soil and sand placed into a 20-foot by 20-foot area of the tunnel on May 10, a day after a hole was discovered in the roof of the tunnel. Workers left about four feet of soil still covering the collapsed portion of the tunnel and installed pipes for grout, ventilation and visual verification. 

The grout is engineered to flow easily, allowing it to encapsulate the materials and rail cars inside Tunnel 1, providing shielding to workers and the environment. The grout has characteristics that will allow it to flow the length of the tunnel and fill in the areas around the equipment inside the tunnel. 

Grout will be placed in lifts, or layers. Each lift will be allowed to set up before the next layer of grout is placed in the tunnel. Workers will use video cameras to monitor the grouting to confirm the tunnel is filled. As the injected grout displaces air inside the tunnel, that air will be filtered as it exits the tunnel, as a precaution. To ensure worker safety, air monitoring stations have been set up around the tunnel to notify workers of any change in conditions. 

During the evening of Oct. 3, after 15 truckloads of grout were injected into the tunnel, workers noticed some subsidence, or dirt settling, around the trench box at the injection location.  Workers then stopped the grouting activity.  No radiological readings above those anticipated were detected, and none of the workers were at risk. This type of an event has been planned for, and soil/sand and equipment previously staged at the work site will be used to fill the subsidence.  The Department of Energy anticipates grouting to recommence soon. 

"The workers are highly skilled and prepared for situations like the subsidence encountered when injecting grout to stabilize the tunnel," said Doug Shoop, Manager of the DOE Richland Operations Office. "There is no question about the difficulty of the work, but we will work safely and methodically to fill up the tunnel."

“Our focus remains on safety," said Ty Blackford, President and Chief Executive Officer, CH2M HILL Plateau Remediation Company. "The entire team from planning, engineering, procurement to the workforce has done a great job getting us to this point in helping to stabilize the tunnel."