The University of Arizona plans to shut down its 51-year-old nuclear reactor by mid-2010, ending a half-century of specialized nuclear research and training at the Tucson school.
The writing has been on the wall for the reactor's demise since the late 1990s, said the professor who runs the UA Nuclear Research Lab. That's when falling demand for nuclear engineers led the university to end specialized degree programs that had fed hundreds of engineers into the nuclear Navy and private nuclear industry.
The reactor's license from the Nuclear Regulatory Commission expires next year, and with a rigorous re-licensing process, the decision was made to shut the reactor down.
"It's obviously showing its age, but really the reason is the mission largely went away with the degree programs," John Williams, the Nuclear Reactor Lab's director, said last week. "We're still doing some research, but not really enough to justify us reapplying for a license."
The small facility is also used for testing materials and electronics that need to resist radiation, such as those launched into space. If hooked up to a generator like a commercial reactor, it could power just a handful of average homes; in comparison, the three commercial reactors at the Palo Verde Nuclear Generating Station run by Arizona Public Service west of Phoenix can power about 4 million homes.
The university will continue to use two other nuclear devices, low-dose and high-dose gamma ray irradiation facilities.
The university applied for a reactor decommissioning license in May, and the NRC published it in the Federal Register and formally requested public comment last week. The document said the reactor is expected to be shut down on May 22.
"Given that it's a research reactor and a fairly small one, one would reasonably expect it would take less than a year for the staff to say 'yeah' or 'nay,'" on the decommissioning plan, said Scott Burnell, an NRC spokesman.
Documents filed with the NRC show that engineers expect no significant residual radiation after removing the reactor and its control and cooling components. They expect the university's Engineering Building to be released for other uses within a year of the start of dismantling.
The plan estimates that decommissioning will cost $2 million. Williams said the university would come up with the money, although it has not yet been identified.
The small reactor was built by General Atomics and was only the second of its type installed. About 60 of the reactors have been built, of varying capacity. About half are still running, with the UA's being the oldest. The first was built at General Atomics' La Jolla, Calif., facility and was shut down in 1997.
The one at the UA is called a TRIGA, which means "Training, Research, Isotopes, General Atomics." According to a General Atomics history of its TRIGA program, the reactors are designed to be so inherently safe that even if all the control rods were removed at once, it would not cause an accident.
Only two minor radiation leaks are noted in the decommissioning report submitted to the NRC and none contaminated the building or people. One happened in 1974 when a slightly damaged fuel element released gas bubbles and an alarm sounded; a small leak in a cooling coil in 1997 is suspected of slightly contaminating that device.
The first step in the decommissioning process would be to remove the approximately 5 pounds of Uranium-235 fuel on loan from the U.S. government. The reactor itself and its support equipment would be removed, the building swept for contamination and returned for other uses. The equipment would be sent to a radioactive waste storage facility.
Williams said some have asked if the reactor could be configured for other uses, but because of its small size and specialized design, that's not possible.
"We've been asked by a lot of people to not shut it down, particularly some alumni, APS, people from the Department of Energy have asked us, but we haven't identified a good reason to keep it operating," he said.
Williams said that over the life of the nuclear engineering program, an estimated 650 people graduated with bachelors, masters or doctorate degrees. About a third went on to operate U.S. Navy reactors, with a few others going into specialized fields like nuclear medicine.
"About half the remainder would have gone to the nuclear industry." Williams said. "A lot have been or are at Palo Verde."