The Savannah River Site expects in 2019 to use a mixture of new and old methods to increase removal of mercury from its liquid waste system.
In late 2017, officials at the Department of Energy facility in South Carolina discovered they could raise pH levels in the waste evaporator tank, a part of the site’s Defense Waste Processing Facility (DWPF). This draws more mercury from DWPF and the site’s entire liquid waste system, demonstrated by routine testing that shows mercury levels have largely remained level even as the material is naturally produced during waste treatment operations.
In addition, Savannah River in 2019 plans to increase removal by installing equipment that will enable direct pumping of mercury out of the DWPF. “Installation of mercury removal equipment into DWPF is being coordinated with adjacent equipment replacements in 2019,” a DOE spokesperson said via email.
The equipment is needed because the mercury often builds up in the system rather than flowing to the spots where it can be removed.
The Savannah River Site liquid waste system includes more than 40 storage tanks that house roughly 35 million gallons of radioactive, Cold War-era material. It encompasses waste processing operations including the Defense Waste Processing Facility, which converts some of that waste into a less harmful form suitable for interim storage on-site.
At any given time, about 60 metric tons of mercury inhabit the site’s tank farms and facilities, according to the spokesperson. The material dates to its use as a dissolvent of reactor fuel during decades of nuclear material processing operations at Savannah River’s H Canyon. When mercury is removed from the liquid waste system, it is recycled back to H Canyon for reuse.
