Back in spring 2017, the older of the 2 radioactive waste disposal tunnels partially collapsed. Extreme wet conditions in the region may have contributed to the collapse. Local communities were alerted but, fortunately, officials announced that the air was not contaminated by the radioactive leakage. The 110-meter tunnel was constructed in 1956 and contained 8 rail wagons filled with radioactive waste.
The next day, the Washington State Department of Ecology had the second tunnel, which was completed 8 years later with a length of 520 meters and holds 28 rail wagons, evaluated. The inspection found that the tunnel was under the risk of a potential failure, however, officials were highly alerted after a video evaluation, conducted in 2018. The footage showed that steel elements had rusted. Steel beams that were used to reinforce the tunnel after some initial construction issues were also damaged along with the bolts that were used for their anchorage. Experts stated that a beam's failure may have be devastating as it could trigger the collapse of multiple structural parts.
The tunnel was filled with 30,000 m3 of grout as a temporary measure to prevent a potential failure. The attempt that lasted for about 7 months, was successfully completed by May, 2019. In the future, radioactive waste will be removed from the underground structure. "We've significantly reduced the risk of contaminating Hanford workers, the public or the environment," Brian Vance, Department of Energy manager for the Hanford nuclear reservation, stated.
Some stated that grouting may not be the optimum solution as radioactive waste could be left in the ground for good. However, according to Ecology officials, "opponents raised legitimate concerns, but in the end those concerns did not outweigh the potential environmental and safety threats that could have been posed had the tunnel collapsed and exposed its highly radioactive contents."