National Research Council. "Herbert G. MacPherson." Memorial Tributes: National Academy of Engineering, Volume 7. Washington, DC: The National Academies Press, 1994. 1. Print.
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Memorial Tributes: Volume 7
student in my lectures on chain reactor theory; I quickly realized that he was the best student in the class.
MacPherson continued to work on graphite at National Carbon, serving as assistant director of research from 1950 to 1956. He then joined the Oak Ridge National Laboratory (ORNL), where he became the leading proponent of molten fluoride-fuelled, graphite-moderated reactors. Such reactors theoretically showed great promise as a cheap alternative to the mainline plutonium-fuelled liquid-metal-cooled fast breeder (LMFBR). Because the fuel in molten fluoride reactors was a liquid, chemical recycle to remove fission products was much simpler than the recycling of solid fuel elements, such as are used in the LMFBR. The promise of molten-fluoride breeders was recognized by the Atomic Energy Commission (AEC) in its 1962 report on civilian power; molten-salt breeders, based on thorium-U233 cycle, were given a priority equal to that of the LMFBR in this report.
During all of his fourteen years at ORNL, the last six years of which he served as the deputy director of the laboratory, MacPherson continued to be the intellectual force behind the molten-salt reactor. His ideas culminated in the very successful Molten Salt Reactor Experiment (MSRE). This reactor, operating at 7500 kW and 1200°F, consisted of a graphite cylinder through which circulated a molten fluoride salt containing U235 and Th232. The MSRE operated remarkably well for three years beginning in 1966. During 1969 it operated with U 233 as fuel, the first nuclear reactor to be fuelled with this isotope of uranium. The MSRE was perhaps the most ingenious and daring engineering experiment ever conducted at ORNL. But, largely for nontechnical reasons, molten-salt graphite-moderated reactors were eventually dropped by the AEC in favor of the LMFBR.
Mac himself, although he took this loss of support philosophically, left ORNL in 1970 to become professor of nuclear engineering at the University of Tennessee (UT). In December of 1973, with support from the White House's Federal Energy Office, I undertook to establish the Institute for Energy Analysis (IEA); but before I could start the institute, I was
