AIKEN, S.C. - Employees in the Savannah River Site ’s (SRS) recently replaced one of the facility’s two dissolvers for the first time in a decade, allowing the facility to perform its vital national security mission even faster.
H Canyon’s mission is to blend down highly enriched uranium (HEU) spent nuclear fuel (SNF) from domestic and foreign research reactor fuel into low enriched uranium (LEU). LEU can be used to make fuel for commercial power reactors and is also less attractive to terrorists than HEU.
The first step of the chemical processing that turns the HEU SNF into LEU, dissolving the fuel, is done in large stainless-steel tanks called dissolvers. DOE recently assigned H Canyon the mission to dissolve High Flux Isotope Reactor (HFIR) cores, which are shorter and have a larger circumference than Material Test Reactor fuel, which H Canyon’s two existing dissolvers were designed to accommodate.
“This new mission required us to replace one of the dissolvers and reconfigure the other one to accept HFIR," DOE Nuclear Materials Manager Maxcine Maxted said. “Being able to use two dissolvers for two different types of SNF will allow us to process material more quickly and more efficiently utilize H-Canyon. This reduces liability for the government, reduces long-term costs, and helps make the world safer."
Remote control cranes are used for most maintenance and processing activities in the canyon, protecting workers from radiation. Highly skilled crane operators can do all needed work using video cameras and crane controls from a crane control room.
“This is the first time we have had to replace a dissolver since 2008," Maxted said. “Many of our crane operators had never seen this done with the cranes, so they learned how to perform the operation safely and efficiently."
The new dissolver took two years to fabricate by an off-site vendor. A large site team that included Savannah River National Laboratory personnel performed startup testing and ensured the dissolver was safe and ready to be placed into the canyon.
H Canyon is the nation’s only operating, production-scale, radiologically shielded chemical separations facility. Uranium is recovered from spent nuclear fuel rods through a complex chemical process in which fuels are dissolved and run through solvent extraction cycles that remove impurities in the fuel. The uranium then mixes with natural uranium in a process called “blend down," and is loaded in shipping containers for shipment off-site.
Source: U.S. Dept. of Energy, Office of Environmental Management
