The University nuclear reactor ceased operations in July 1998 and is now undergoing decommission, or complete dismantling. In light of the recent accident at the Uranium Processing Plant in Japan, a question now surfaces: Did the reactor, called UVAR, ever pose a health threat at the University?
UVAR was commissioned in 1961 at a cost of $1 million ($8 to $10 million today) with the sole purpose of providing research opportunities to students enrolled in the Mechanical and Nuclear Engineering program. With a capability of producing only two mega watts of power -- compared to commercial reactors, which produce up to 1200 MW -- the reactor was only used to generate electricity, but in radioactive and neutron beam experiments.
Decommissioning
Just a 10-minute walk away from new dorms, up Observatory Hill, through dense undergrowth and beyond a metal wire fence, lies the remnants of UVAR.
The heart of the reactor -- the core -- where nuclear fission reactions took place, now has been sent back to the Department of Energy, leaving empty the 20-foot-deep swimming pool in which it was submerged. The last of the waste has been sent to North Carolina for disposal and burial. The uranium fuel elements are no longer present. All that remains is for the swimming pool water -- the primary coolant -- to be filtered and discharged to the environment, for the hole in the floor to be filled and the dome room, once capable of withstanding increases in pressure, to be renovated for other use.
But how safe is all of this?
University Radiation Safety Specialist Debby Steva, responsible for the decommissioning process, said the decommissioning team recently hired a company to survey the entire building and environment -- the surrounding area in addition to the reactor itself.
"They took soil and water samples to determine the radioactive presence in the environment," Steva said.
The preliminary findings indicate UVAR is a relatively clean facility and decommissioning therefore won't be too expensive. The next step is a plan that calls for the removal of the large reactor parts, the piping and concrete, and the demolition of the pool. Once approved by the federal Nuclear Regulatory Commission, the decommissioning itself is expected to take six to eight months. A final survey will then be carried out.
Steva said there will be low levels of radioactivity after the decommissioning but not high enough to give anyone a significant, detectable dose.
She said that even while the nuclear reactor was in operation, the danger of exposing the surrounding community to radiation was minimal due to the small size of the reactor.
"Even if the pool drained and we couldn't control the reaction, by the time it reached the nearest people, it would not be life-threatening," she added. "A study was done of a worst case scenario -- there would not be a serious enough release beyond the fenced area."
The experiments
Nuclear fission (not to be confused with fusion) is the process by which heavy, unstable nuclei such as uranium-235 are stimulated to decay into lighter, more energetically favorable nuclei. In doing so, they release energy. This fragmentation is induced by a single neutron, and each reaction generates an average of 2.5 more neutrons, each causing fission, and giving rise to a chain reaction. The lighter nuclei are fission byproducts and often are not completely stable. They decay by various modes, amounting to a possible 250 different byproducts from a single U-235 reaction. Unless used in some beneficial manner such as industrial or medical application, this becomes radioactive nuclear waste.
The most prevalent byproduct is cesium 137, which has a half-life of 30 years. The half-life is the average time taken for half the number of nuclei initially present to decay. It provides a measure of how potent the sample is, i.e. how long it will remain radioactive. Other byproducts include technicium 99, the most commonly and diversely used radioactive isotope in hospitals.
Apart from producing a rich cocktail of elements, UVAR also provided a bountiful source of neutrons. UVAR Manager Paul Benneche explains that the reactor, while principally used for experiments, also rendered a service to industry and partially maintained itself on this self-generated income. The reactor produced specimens for radioactive tracing in the oil industry. It performed neutron radiography -- imaging similar to that of X-rays. The food industry utilized the reactor to determine the concentration of specific elements in food samples.
Among the experiments done at the reactor was the excitation of elements to become radioactive by simply throwing them into the reactor. Consequently, one could analyze either the radiation damage or the positive mutations caused by damage on other structures, Benneche said.
One particularly exciting request was to provide a radioactive source for a Mir space station experiment, which was observing the diffusion of liquid metals through solid metals.
The reactor even played a role in the gemology industry, irradiating clear topaz stones and developing them to their familiar bluish sheen.
In its final days, the reactor's neutron beams were employed to investigate cures for cancer.
One such experiment was Boron Neutron Capture Therapy. In the experiment, the element boron, which can be cancer-seeking, was injected into a patient and actually attached to cancerous growths. The patient then would be placed in the neutron beam, and boron, being a good absorber of neutrons, would undergo fission. The byproducts -- helium and lithium -- emerged in small enough quantities to not cause damage in the body, but the energy deposited in the cancerous cell was sufficient to kill it.
Sixty mice with breast cancer showed appreciable shrinkage of their tumors, Benneche said.
The future of nuclear power reactors
The decision to close UVAR reflects the growing trend in America that the nuclear power industry is waning.
Hadyn Wadley, Engineering School dean of research, said the number of graduate students involved in the Engineering School's program had decreased, faculty had retired, the plant was costly to operate, and research had dwindled.
"It was felt that resources could better serve students in other ways," Wadley said.
Students have developed interests in other areas and, "as a small school we need to focus on the things that are more important," he said.
Benneche attributed the demise to an increase in energy awareness. Since the oil crisis of 1973, when the Organization of Petroleum Exporting Countries came into existence, the increase in energy consumption per year has dropped from 7 percent to between 2 and 3 percent.
Government projections for the next century predict an increased use of gas power plants, Benneche said.
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