EM Richland Operations Office contractor CH2M HILL Plateau Remediation Company tests an off-site mock-up of a conveyance system that will be used to move engineered grout from trucks into three at-risk underground structures.
EM Richland Operations Office contractor CH2M HILL Plateau Remediation Company tests an off-site mock-up of a conveyance system that will be used to move engineered grout from trucks into three at-risk underground structures.

RICHLAND, Wash. – A Hanford Site project to stabilize three at-risk underground structures with engineered grout is well underway, with workers starting field preparations this month after successfully testing a full-scale mock-up of the grouting system earlier this summer.

The three structures, located near the former Plutonium Finishing Plant on Hanford’s Central Plateau, received liquid waste during Hanford’s plutonium production operations and contain residual radioactive and chemical contamination. A 2019 report indicated the structures are at risk of age-related failure.

EM Richland Operations Office (RL) contractor CH2M HILL Plateau Remediation Company (CHPRC) is filling the structures with engineered grout to protect workers and the environment, while not precluding future remedial actions or final closure decisions.

“This work is critical to Hanford’s ongoing risk reduction mission,” said Al Farabee, Hanford’s senior technical advisor for the project. “We are confident in the process, having used grout to safely stabilize other at-risk structures on the Hanford Site, most recently PUREX Tunnels 1 and 2.”

Engineered grout will be pumped from trucks through more than 1,500 feet of pipe to stabilize three underground structures at the Hanford Site.
Engineered grout will be pumped from trucks through more than 1,500 feet of pipe to stabilize three underground structures at the Hanford Site.

Last month’s off-site mock-up tests provided another boost of confidence for the project.

“We learned valuable lessons about the grout conveyance system,” said Delise Savior, CHPRC project manager. “It let us see firsthand what would and would not work, and allowed us to fix those issues in a clean environment before we started work in radiologically contaminated areas.”

This animation shows the grout delivery and conveyance system that will be used to safely stabilize the structures. The use of grout will provide additional protection, while not precluding future remedial actions or final closure decisions.

Grouting is expected to begin this fall with project completion scheduled near the end of the 2020 calendar year. For more information, visit the stabilization project webpage.