The US Department of Energy has proposed a new phased approach for clean-up of the Hanford waste storage site in Washington state. The site, which is currently storing 56 million gallons of chemical and radioactive waste, was used in connection with plutonium production during World War II and the Cold War.
US secretary of energy Ernest Moniz described the clean-up effort as one of the ‘highest priorities’ for the DOE. He said that it is critically important for the department to continue working closely with the state of Washington on the clean-up.
The new framework approach has been developed in light of technical issues that have emerged with parts of the Waste Treatment and Immobilisation Plant (WTP). The WTP comprises a pre-treatment facility for separation of low-activity and high-activity waste; two separate facilities for vitrification of the low- and high-activity waste streams, an analytical laboratory, and associated auxiliary facilities/infrastructure.
‘The current design requires that all waste treated at the WTP be processed through the pre-treatment facility, but this requires waiting until the technical issues are resolved,’ Moniz said.
"Therefore, we have identified an alternative approach for immobilising waste as soon as we can, while simultaneously resolving the remaining technical challenges at both the PT and the HLW facilities."
The phased approach would start with immobilising the low-activity portion of the waste. It would go straight to the plant’s low activity waste facility, bypassing the pre-treatment facility.
DoE also suggests that immobilisation of the tank waste should begin as soon as practicable and proposes that transuranic (TRU) tank waste is sent for disposal at the Waste Isolation Pilot Plant (WIPP) in New Mexico.
This multi-pronged, phased approach to the startup and completion of the tank waste mission is intended to facilitate the start of tank waste immobilisation as soon as practicable while work continues to resolve the technical issues in the PT and HLW facilities.