A tunnel collapse at the United States’ main nuclear waste store caused the US Department of Energy (DOE) to declare an emergency this week.
On the morning of 9 May, a rail tunnel used to transport spent fuel rods to a plutonium extraction facility collapsed at the Hanford Site in Washington State. The DOE said the cave-in involved a 20-foot-long section where two tunnels intersected, reported CBS.
No workers were in the tunnel at the time.
In a video of the moment captured by a Hanford worker, a voice over a public address system can be heard saying, "This is an emergency. Take cover immediately."
After a few hours, restrictions were lifted for some workers and the department announced that there had not been any leakage of radioactive material.
"This is a serious situation, and ensuring the safety of the workers and the community is the top priority," said Washington State Governor Jay Inslee in a statement on the day. "Our understanding is that the site went into immediate lockdown, in which workers were told to seek shelter, and all access to the area has been closed."
According to the DOE, the collapse may have been caused by road crews doing construction above the tunnel.
Hanford is the main repository for US nuclear waste going back to the wartime Manhattan Project. Its 177 underground tanks contain 53 million gallons of radioactive sludge. Over the years, 67 of these have leaked a million gallons of radioactive waste and around 61 square miles have been contaminated.
The DOE is planning to "vitrify" high-level radioactive waste stored in Hanford and put it in a permanent storage in Nevada. This was originally to be completed by 1998, however the vitrification plant is still under construction.
Image: Hanford released this picture of the tunnel, showing the area of the cave in.