DOE Digs Up Molten Salt Nuclear Reactor Tech, Los Alamos To Lead the Way Back

After more than 50 years, molten salt nuclear reactors might be making a comeback. The US Department of Energy (DoE) has tapped Los Alamos National Laboratory (LANL) to lead a $9.25 million study into the structural properties and materials necessary to build them at scale. The Register reports: "The US needs projects like this one to advance nuclear technologies and help us achieve the Biden-Harris administration's goals of clean energy by 2035 and a net-zero economy by 2050," said Asmeret Asefaw Berhe, director of the office of science, in a statement. The study, conducted as part of the Scientific Discovery though Advanced Computing (SciDAC) program, seeks to gain a better understanding of the relationship between corrosion and irradiation effects at the atomic scale in metals exposed to molten salt reactors through simulation. This isn't the first time the DoE has explored this reactor tech. In the middle of last century, Oak Ridge National Laboratory (ORNL) took the lessons learned from the Aircraft Reactor experiment to build a functional nuclear aircraft power source and began construction of a molten salt test reactor. The experiments, conducted between 1957 and 1969, utilized a mixture of lithium, beryllium, zirconium, and uranium fluoride salts. Cooling was also achieved using a fluoride salt mixture, but it lacked the uranium and zirconium found in the fuel. The experiments proved promising, as molten salt reactors were generally smaller and considered safer compared to the pressurized water reactors still used today. But both proved too heavy for powered flight or materials design. Because cooling was achieved by circulating molten salt through a heat exchanger as opposed to water, the risk of a steam explosion is effectively nonexistent. However, as the Oak Ridge National Laboratory found during the Molten Salt Reactor Experiment, fluoride salts are incredibly corrosive and required hardened materials to safely contain them. "ORNL's Molten Salt Reactor Experiment utilized specialized materials fabricated from Hastelloy-N -- a nickel-molybdenum alloy developed by the lab with a high resistance to corrosion even at high temperatures," adds the reports. "The research program announced this week will revisit the material choices and examine a variety of metals using higher-performance compute resources to simulate how they'll perform at scale in these reactors."

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