Idaho National Laboratory has completed treating irradiated fuel from Hanford's Fast Flux Test Facility, except for some fuel that will be saved for research.
The fuel was shipped to Idaho because the national lab has experience treating fuel bonded with sodium. It had a similar reactor, the Experimental Breeder Reactor-II, another "fast" reactor. The Hanford and Idaho reactors used sodium for cooling.
Idaho National Laboratory's Materials and Fuels Complex was built next to the Experimental Breeder Reactor-ll to safely handle and treat its spent fuel in an argon atmosphere to eliminate the risk of sodium reactions.
The FFTF fuel also needed to be handled in an inert atmosphere to prevent potential explosions if exposed to air and water.
FFTF's sodium-bonded fuel assemblies were shipped to Idaho from October 2007 through spring 2008 and stored at the Materials and Fuels Complex's Hot Fuel Examination Facility while engineers designed and built a way to disassemble the fuel assemblies.
Work began in September 2010 to treat the fuel. Uranium was extracted at the complex's Fuel Conditioning Facility using an electro-metallurgical treatment process. Pieces of the rods were dissolved in a bath of molten chemical salts and subjected to an electric current. Uranium from the fuel would gather on a steel rod inserted into the molten salt.
Extracted uranium 235 then was blended with uranium 238 and cast into low-enriched uranium ingots. No decision has been made on the future of the ingots. In addition, small amounts of other radioactive substances, such as americium and plutonium, werecaptured in the molten salt for formation into ceramic ingots for disposal.
About 550 pounds of sodium-bonded fuel was sent to Idaho, and about 482 pounds of that was treated. The rest will be kept in storage for use by Idaho National Laboratory's nuclear fuels research programs.
The treatment work was completed on time and within the $23.6 million budget, according to Idaho National Laboratory.
The Idaho lab still has110 pounds of unirradiated sodium-bonded fuel from FFTF. FFTF also hadabout 375 fuel assemblies without sodium bonding that are being stored incentral Hanford until a decision on their disposal is made.
FFTF, a 400 megawatt-research reactor, operated from 1982 to 1992, but has been shut down to a condition which requires minimal surveillance and maintenance since 2009. The reactor had been maintained on standby to allow it to be efficiently restarted until Democratic and Republican administrations concluded that it had no financially viable use.
When FFTF operated, it produced a variety of medical and industrial isotopes and provided research and testing of components and systems for advanced nuclear power systems.