Since 1966, researchers have depended on the HFIR's neutrons to unlock the molecular secrets of materials and to provide radioisotopes for a number of medical, industrial and academic uses. Neutrons, which are subatomic particles that carry no charge, can penetrate deeply into materials and then scatter. From that scattering, researchers can derive structural information that aids in the development of advanced materials including polymers and superconductors.
The medical community looks to the HFIR - pronounced "hifer" - to provide radioisotopes used for vital diagnostic and therapeutic purposes. The HFIR is the nation's only source of one of those radioisotopes, californium-252.
The HFIR has served the scientific community continuously during its three decades except for a three-year pause in the 1980s, when the safety conditions of the DOE reactors were reviewed in the wake of the Chernobyl accident in the Soviet Union.
Operational performance is one of the strengths of the ORNL reactor program, however. The light-water reactor is subject to one of the nuclear industry's most rigorous safety programs, in which procedures to the most minor detail are meticulously followed. The result over the years has been a shining record of continuous, reliable, and safe operation.
One of the HFIR's most celebrated performances was an analysis of bits of the remains of U.S. President Zachary Taylor. That analysis debunked a theory that the 19th century commander-in-chief, who died in office, was poisoned.
Unlike the pulsed stream of neutrons in an accelerator, the steady stream of neutrons from nuclear reactors is better suited to functions such as the production of medical isotopes, irradiation of materials for research, and the analysis of environmental samples. Reactors can produce beams of high-energy neutrons or cold neutrons, which are neutrons that are literally chilled to a crawl to make them interact better with materials.
ORNL's leading tool for peaceful research was conceived, ironically, during the height of the Cold War in response to a Soviet announcement of an advanced reactor project to produce nuclear materials. According to ORNL retiree Dick Cheverton, who helped design the HFIR and still consults for the laboratory, "The Soviet announcement greatly worried Glenn Seaborg, the Nobel Prize winner who was then chairman of the Atomic Energy Commission." Cheverton and some colleagues had designed a flux trap research reactor as a thesis project.
"We told Seaborg we knew exactly what to do," Cheverton said. "We had the plans for a better one."
HFIR is part of a DOE upgrade plan that would refurbish the reactor and add facilities that would make it, for a very reasonable cost when compared with a new facility, one of the world's top neutron research resources.
Entering its fourth decade of service, the reactor is up to the task. Calculations on the reactor vessel indicate that it is good for another 40 years. The facility, in other words, is in its prime of life. That's 40 years for countless more research projects to take advantage of the HFIR's capacity for splitting uranium atoms.
ORNL, one of DOE's multiprogram research facilities, is managed by Lockheed Martin Energy Research Corporation.