Hanford emergency ends as collapsed tunnel sealed

11 May 2017

The site emergency declared on 9 May at the US Department of Energy's (DOE's) Hanford Site in Washington State has now been lifted. Late last night, workers at the site completed filling in a hole that appeared after the roof of a tunnel containing contaminated material collapsed.

Hanford tunnel filling in - 460 (DOE)
Workers filling in the collapsed Hanford tunnel (Image: DOE)

The DOE's Richland Operations Office announced at 11.21pm that the emergency at Hanford had been terminated. The announcement came shortly after workers completed filling in the hole with some 53 truckloads - about 420 cubic meters - of soil.

The DOE said, "Before allowing uncontrolled access to the area where the partial tunnel collapse occurred, officials plan to take additional near-term actions to ensure the safety of the workforce and the public." These may include placing a cover over the entire length of the tunnel, it said. Workers will also identify and implement longer term measures, the DOE said.

No radiological contamination was detected as a result of the tunnel collapse or during the filling of the hole. The DOE said, "Until additional actions can be taken to ensure safety," access to parts of the Hanford site will continue to be restricted. However, it expected most Hanford workers to be on a normal work schedule today.

Hanford was the site of US military plutonium production activities from 1943 until 1987. The site - with nine nuclear reactors and associated processing facilities - is now managed by the DOE's Richland Operations Office, which is responsible for the cleanup of all remaining waste streams at the site.

Two tunnels were constructed in the 1950s and 1960s next to the former Plutonium Uranium Extraction Plant (PUREX) located in an industrial area near the centre of the Hanford Site called the 200 East Area. The tunnels - constructed of wood and concrete and covered with about 2.5 meters of soil - were built to hold rail cars that were loaded with contaminated equipment. One tunnel, about 110 meters long, contains eight rail cars loaded with contaminated equipment. This tunnel leads into a longer tunnel that contains 28 rail cars loaded with contaminated equipment. The tunnels were sealed in the mid-1990s and are checked periodically.

The Richland Operations Office declared an alert at around 8.30am on 9 May after a 20-foot (6-meter) section of the shorter tunnel was found to have collapsed. The alert led to the precautionary sheltering of employees in the vicinity of the PUREX plant. The alert was later expanded to a site area emergency.

Greg Walden, chairman of the House of Representatives' Energy and Commerce Committee, said yesterday, "While there have been no reports of injuries, and no indication of a release of contamination, as chairman of the committee I have asked DOE to provide a bipartisan briefing for members and staff on the situation." He added, "I am continuing to monitor the situation as the facts develop, and I look forward to DOE assisting the committee in understanding the circumstances that contributed to the cave-in and regarding concerns related to operations at the Hanford Site."

Researched and written
by World Nuclear News

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