New US liquid metal nuclear fuel could boost energy output of reactors

Oak Ridge National Laboratory (ORNL) has partnered with Australian investment firm Out The Back Ventures to advance a novel nuclear fuel technology called Uranium Dioxide Liquid Metal Suspension (ULIMES). This innovative approach replaces the traditional solid uranium dioxide (UO2) fuel pellets used in most U.S. light water reactors (LWRs) with unsintered UO2 particles suspended in a liquid metal carrier. The circulating liquid fuel system enables continuous movement through different neutron flux zones, promoting uniform fuel burnup and eliminating inefficiencies caused by the “self-shielding” effect in conventional solid fuels. The ULIMES technology offers significant safety and efficiency improvements. The liquid metal carrier enhances thermal conductivity, allowing better reactor cooling, lower peak fuel temperatures, and reduced material damage from fission gases and radiation. Additionally, ULIMES is chemically compatible with existing reactor materials, facilitating integration without the need for extensive new material qualification programs. This compatibility could reduce costs and accelerate deployment by bridging current reactor designs