High Flux Isotope Uranium Reactor Back on Line

A high flux isotope reactor went online after more than a year of repairs, systems checks and improvements that cost more that $70 million. It's a research reactor at the Department of Energy's Oak Ridge National Laboratory internationally recognized as a neutron source for materials studies and isotope production.

New and improved, it now has a set of modern experiment instruments, like beam lines to channel neutrons, a new beryllium reflector and a powerful refrigeration system added to cool the reactor's neutron beams to minus 425 degrees Fahrenheit (-254 Celsius).

The extremely low temperature is required to slow down the neutrons and to increase their wavelength, which makes it easy for scientist to study "soft" materials such as proteins and polymers and to analyze materials with certain magnetic properties.

Neutrons are vital to research in physics, chemistry, engineering and other materials-related fields. At room temperature, they are ideal for use in special instruments to illuminate the atomic structure and dynamics of hard, dense materials.

Greg Smith, who leads ORNL's Low Q Neutron Scattering Group, said 49 science experiments are scheduled for this summer, which will study many possible practical applications as well as theoretical models.

Among the applications to which the reactor will contribute are new, polymer nano-composites, which are "hard" nanoparticles surrounded by a "soft" polymer matrix with useful properties, or crystals constructed from membrane proteins, which determine interaction and communication between living cells and can improve studies on the structural and functional properties of the membrane proteins.

It will also produce radioisotopes, used in nuclear medicine and industrial analysis.

"We anticipate eventually providing neutron beams for eight to ten reactor cycles per year and no major shutdown for a beryllium reflector replacement until after 2020," Smith said. "In the meantime, HFIR users will soon be able to access thermal and cold neutron beams of world-class brightness."