RICHLAND – A landfill for low-level radioactive waste at the nation’s most contaminated nuclear site has room to expand, but an advisory board is concerned about the levels of radioactivity there.
The landfill at the Hanford Nuclear Reservation already contains 60 percent to 70 percent of the allowable amount of some key radionuclides.
As a result, the Hanford Advisory Board is recommending that the U.S. Department of Energy review those limits, which are based on an assessment that is about 15 years old.
The federal government created Hanford in the 1940s as part of the top-secret Manhattan Project to build the atomic bomb.
Today, work there centers on cleaning up the radioactive and hazardous remnants of plutonium production that continued through the Cold War.
The Environmental Restoration Disposal Facility is the onsite landfill that accepts most of the contaminated soil being dug up near the Columbia River, as well as debris from contaminated buildings that are being demolished.
More than 8 million tons of waste have been placed in the landfill. An expansion is under way.
The Energy Department says radionuclide limits were based on a conservative assessment that didn’t take into account protection measures, such as a bottom liner and a protective cap that will be placed over its top when the landfill is filled and closed.
“It appears likely that ERDF’s ultimate capacity may be limited by the inventories of certain key radionuclides … rather than the volume of wastes disposed, with a consequence that acceptance of wastes containing these radionuclides may be limited,” the board wrote in advice to the Energy Department at its June meeting.
The board said it supports the expansion of the landfill as long as it is done in a way that protects human health and the environment over the long term.
It said the Energy Department should consider new information about the way contaminants may move through the soil.
The agency also may need to consider additional treatment of wastes disposed of at the landfill to minimize the chance they could contaminate groundwater, the board said.
The board recommended that the Energy Department create a tracking system for radioactive contaminants that could end up in the landfill and keep a running summary of remaining capacity.