FILE - This May 9, 2017, file photo, provided by the U.S. Department of Energy, shows a 20-foot by 20-foot hole in the roof of a storage tunnel at the Hanford Nuclear Reservation near Richland, Wash. The U.S. Department of Energy says there is a high risk that a second tunnel filled with radioactive waste might collapse on the Hanford site. This section of tunnel partially collapsed at the site, forcing some 3,000 workers to seek shelter for a few hours. (U.S. Department of Energy via AP, File)
This image provided by the U.S. Department of Energy shows a 20-foot by 20-foot hole in the roof of a storage tunnel at the Hanford Nuclear Reservation near Richland, Wash., Tuesday, May 9, 2017. An emergency was declared Tuesday after the partial collapse of the tunnel that contains rail cars full of radioactive waste. (U.S. Department of Energy via AP)
FILE - This April 2, 2014 file image provided by the U.S. Department of Energy shows workers underground inside the Waste Isolation Pilot Plant facility in Carlsbad, N.M., for the first time since the Feb. 14 radiological release. Workers at a West Texas nuclear waste disposal site are closely monitoring containers from Los Alamos National Lab, Tuesday, May 20, 2014, a day after New Mexico officials announced a type of kitty litter is believed to have caused a radiation leak at the federal government's troubled nuclear waste dump. (AP Photo/U.S. Department of Energy, File)
This April 2, 2014, image provided by the U.S. Department of Energy shows workers preparing to enter the Waste Isolation Pilot Plant facility in Carlsbad, N.M., for the first time since the Feb. 14 radiological release. The operators of this federal government's troubled nuclear waste dump are bracing for a scathing report Wednesday, April 23, 2014, on their response to a radiation release that contaminated 21 workers and shuttered the southeastern New Mexico facility two months ago. (AP Photo/U.S. Department of Energy)
This April 2, 2014, image provided by the U.S. Department of Energy shows workers underground inside the Waste Isolation Pilot Plant facility in Carlsbad, N.M., for the first time since the Feb. 14 radiological release. The operators of this federal government's troubled nuclear waste dump are bracing for a scathing report Wednesday, April 23, 2014, on their response to a radiation release that contaminated 21 workers and shuttered the southeastern New Mexico facility two months ago. (AP Photo/U.S. Department of Energy)
In this March 7, 2014 photo released the U.S. Department of Energy, specially-trained workers have placed a camera atop an elevator to make unmanned tests inside a nuclear waste dump in Carlsbad, N.M. They are finalizing plans to enter the nation's only underground nuclear waste dump after two separate incidents forced its closure weeks ago, including a leak that exposed more than a dozen workers to low levels of radiation. Officials with the DOE's Waste Isolation Pilot Plant say initial testing shows there's no contamination at an air intake shaft that leads into the mine or at the bottom of the mine's salt shaft. (AP Photo/Department of Energy)
In this March 7, 2014 photo released the U.S. Department of Energy, specially-trained workers place instruments in an elevator to make unmanned tests inside a nuclear waste dump in Carlsbad, N.M. They are finalizing plans to enter the nation's only underground nuclear waste dump after two separate incidents forced its closure weeks ago, including a leak that exposed more than a dozen workers to low levels of radiation. Officials with the DOE's Waste Isolation Pilot Plant say initial testing shows there's no contamination at an air intake shaft that leads into the mine or at the bottom of the mine's salt shaft. (AP Photo/Department of Energy)
In this March 7, 2014 photo released the U.S. Department of Energy, specially-trained workers make unmanned tests inside a nuclear waste dump in Carlsbad, N.M. They are finalizing plans to enter the nation's only underground nuclear waste dump after two separate incidents forced its closure weeks ago, including a leak that exposed more than a dozen workers to low levels of radiation. Officials with the DOE's Waste Isolation Pilot Plant say initial testing shows there's no contamination at an air intake shaft that leads into the mine or at the bottom of the mine's salt shaft. (AP Photo/Department of Energy)
In this March 7, 2014 photo released the U.S. Department of Energy, specially-trained workers make unmanned tests inside a nuclear waste dump in Carlsbad, N.M. They are finalizing plans to enter the nation's only underground nuclear waste dump after two separate incidents forced its closure weeks ago, including a leak that exposed more than a dozen workers to low levels of radiation. Officials with the DOE's Waste Isolation Pilot Plant say initial testing shows there's no contamination at an air intake shaft that leads into the mine or at the bottom of the mine's salt shaft. (AP Photo/Department of Energy)
Former state lawmaker John Heaton tells a panel of officials with the U.S. Department of Energy and the Waste Isolation Pilot Plant the community is frustrated with the release of information following a radiation leak at the underground nuclear waste repository, during a town hall in Carlsbad, N.M. on Thursday, March 6, 2014. (AP Photo/Susan Montoya Bryan)