When a 20-foot section of a 360-foot tunnel at the Hanford Nuclear Reservation near Richland, Wash., collapsed on May 9 this spring, it forced about 3,000 Department of Energy workers to shelter in place for several hours.
The immediate fix to reclose the tunnel originally sealed in 1965 included filling in the hole with 53 truckloads of soil and placing a tarp over the hole to prevent any radioactivity from escaping into the area.
Wednesday, workers began filling the tunnel with grout which will eventually completely fill the space, including the eight railroad cars filled with nuclear waste.
The grout injection procedure will be done at night with material engineered to easily flow into the tunnel and embed the railcars. The remediation work is being performed by CH2M Hill Plateau Remediation. The grouting work should be finished by the end of the year according to the Tri-City Herald.
The Plutonium Uranium Extraction Plant at Hanford was once the manufacturing site for plutonium used for the Manhattan Project during World War II and produced the first nuclear bomb. During the Cold War, Hanford produced enough material for the more than 60,000 weapons built for the U.S. nuclear arsenal. Inadequate safety precautions during production led to Hanford's distinction as the most contaminated nuclear site in the country. The Hanford site's ongoing clean up is expected to last another 40 years and cost upwards of $100 billion.