DOE Completes Evaluation of Hanford's Tunnel 2, Finds 'High' Risk of Collapse

The two PUREX storage tunnels hold mixed radioactive and chemical waste. A section of Tunnel 1 collapsed May 9, and state authorities then ordered DOE and CH2M HILL Plateau Remediation Company to immediately assess the integrity of both.

The U.S. Department of Energy is submitting reports June 30 to state authorities on the structural integrity of two tunnels at the Hanford Site in Richland, Wash., and the reports conclude that both do not meet current structural codes and standards. Doug Shoop, manager of the DOE Richland Operations Office, and Alexandra Smith, program manager for the Washington state Department of Ecology's Nuclear Waste Program, spoke about the findings at a news conference.

A section of one tunnel – PUREX (Plutonium Uranium Extraction) Tunnel 1 – filled with mixed radioactive and chemical waste collapsed May 9, 2017, at the Hanford Nuclear Reservation, and the following day, the department issued an order requiring DOE and CH2M HILL Plateau Remediation Company to immediately assess the integrity of the two PUREX Storage Tunnels and to take corrective actions. "This alarming emergency compels us to take immediate action – to hold the federal government accountable to its obligation to clean up the largest nuclear waste site in the country," Washington Department of Ecology Director Maia Bellon said May 10.

The tunnels are classified as "miscellaneous units" under Washington's Dangerous Waste Regulations, according to the order. The order says the company and DOE had not properly operated and maintained Tunnel 1 and "failed to keep it totally enclosed with a protective covering from the elements and from run-on." Completed in 1956, the tunnel was sealed after being filled between June 1960 and January 1965 with eight railcars filled with mixed waste, it states.

Tunnel 2 is much larger than Tunnel 1. Constructed in 1964, Tunnel 2 is 1,700 feet long and contains 28 railcars loaded with large waste containers. Shoop said the evaluation determined that Tunnel 2 is at "high" risk of localized collapse and should be stabilized as soon as possible. DOE and the contractor are studying how much backfilling was done when Tunnel 2 was built and the amount of compaction that was done; it has not been possible for personnel to enter either tunnel for decades because of the radiological hazards inside them, which makes monitoring their condition more difficult, he said.