Lab Will Mark 50th Anniversary of UA Research Reactor

Reactor has been used for analyzing samples, testing materials and other research

University of Arizona faculty, alumni and others will mark the 50th anniversary of the UA Research Reactor by performing an approach to critical experiment.

The event will be held Dec. 6, exactly 50 years to date after the experiment was first performed at the reactor's commissioning in 1958.

The Atomic Energy Commission issued the initial operating license for the reactor on Dec. 5, 1958, said UA professor John G. Williams, director of the Nuclear Reactor Laboratory.

The next day, the fuel was loaded into the core in an approach to critical experiment, a procedure used to bring nuclear fission reactors to a state of sustained neutron chain reaction for the first time, Williams said.

"The procedure has been followed at every reactor commissioning in the world since Enrico Fermi first brought critical the Chicago Pile CP-1 on Dec. 2, 1942," Williams said.

The UA Research Reactor is a light water reactor fueled with 20 percent enriched uranium in a zirconium hydride matrix. This type of fuel was invented in 1956 by a team of scientists who included Edward Teller and Freeman Dyson, with the goal of producing an inherently safe reactor that could not undergo an unsafe transient, or explosion, under any circumstances, Williams said.

The steady-state power generated by the reactor is only enough to power 100 hair dryers, said Robert Offerle, who supervises the facility.

The reactor is called a "TRIGA" reactor, a trade mark that stands for Training Research Isotope-production General Atomics. General Atomics of San Diego designed the reactor and has been marketing the design since. The UA facility was the first of more than 60 TRIGA reactors that have since been constructed worldwide.

The UA reactor has been used for reactor dynamics research, neutron activation analysis of mineralogical samples – especially meteorites, radiation effects testing and processing of electronic materials, isotope production for biomedical and other research, Williams said.

It also served students in undergraduate and graduate nuclear engineering degree programs in the former department of nuclear and energy engineering until 1998, he added.

This Saturday event, which will be held in the Old Engineering Building, is open by invitation only.