A draft environmental study by the Department of Energy does not recommend a site and disposal method for certain kinds of radioactive medical and nuclear reactor waste.
That means Hanford remains on the list of possible sites for disposal of the waste. However, DOE earlier said it would prefer not to bring the waste to Hanford until the vitrification plant is at full operations, which is expected to be 2022. Other sites under consideration do not have that limitation.
A decision on what to do with the waste, which includes “Greater Than Class C Low Level Radioactive Waste” and similar waste, will be made after a final environmental impact statement is issued, according to DOE. That document will pick a preferred disposal alternative, it said.
Public hearings are planned to provide input on the draft environmental impact statement released Friday before a final decision is made. They include hearings in Pasco on May 17 and in Portland on May 19, but times and locations have not been announced.
DOE is looking for a place to dispose of 190,000 cubic feet of radioactive waste now being stored, plus 230,000 cubic feet of waste expected to be generated during the next 60 years. The waste would cover a football field about seven feet deep.
The waste would contain radioactive activity of about 160 million curies. In comparison, 2,100 tons of uranium would have 14,000 curies of radiation, and the 53 million gallons of waste awaiting treatment in Hanford’s underground tanks have about 190 million curies.
Some of the radionuclides in the waste have half lives of more than 10,000 years — the time it would require half of their radioactivity to decay.
The waste includes concentrated radioactive materials encapsulated in small metal containers for medical use, such as diagnosing and treating cancer, and for industrial use. Such “sealed sources” account for about a quarter of the waste volume.
Unneeded sealed sources are stored at hospitals, construction sites and universities until they can be disposed of, which poses a national security risk, according to DOE. Their concentrated radioactivity and portability could make them a source for dirty bombs, it said.
Safe disposal is important to the future of nuclear medicine, including the planned U.S. production of molybdenum 99, an isotope commonly used in diagnostic medicine, according to DOE. Now molybdenum 99 is imported and the United States has experienced shortages. If the medical isotope is produced in the United States, Greater Than Class C waste will be created and will need disposal, according to DOE.
In addition, radioactive metals from decommissioned commercial nuclear power reactors must be disposed of.
Some of the waste contains isotopes of plutonium and americium in large enough quantities that if they had been produced at Hanford, they would be disposed of at the Waste Isolation Pilot Project, or WIPP, in New Mexico as transuranic waste. Now that repository is used only for defense waste.
Among options DOE is considering is sending the waste to WIPP. It also is considering sending it to Hanford, the Idaho National Laboratory, different sites in New Mexico, the Savannah River Site in South Carolina or the Nevada National Security Site, which was formerly the Nevada Test Site. The possibility of selecting a commercial site also is being considered.
At Hanford, disposal could be in boreholes, vaults or trenches.
However, in connection with negotiations with the state of Washington, DOE amended a different draft study, the Hanford Tank Closure and Waste Management Environmental Impact Statement, to say that its preference is not to send Greater Than Class C waste to Hanford, at least until the vitrification plant is fully operational. The $12.2 billion plant is being built to treat Hanford’s tank waste.
The draft study on the Greater Than Class C waste assumes a start to disposal in 2019, but said the start date is uncertain.
By Annette Cary
The News Tribune