A soft blue glow surrounds the rods that make up the core of Penn State's Breazeale Nuclear Reactor after it has been in use.

The glow, which emanates from the longest operating licensed reactor in the United States, is caused by the charged particles traveling through water at a very high speed. Named after its designer, William Breazeale, the Breazeale reactor has been operating since Aug. 15, 1955.

The reactor was licensed by the AEC as part of President Dwight Eisenhower's "Atoms for Peace" program, to train and educate people on the applications of nuclear technology. During the past 50 years, the Breazeale reactor has played host to more than 100,000 visitors, and has ensured that educational opportunities on peaceful uses of nuclear technology are provided to students throughout Pennsylvania and the surrounding states, said C. Frederick Sears, director of the Radiation Science and Engineering Center.

The Breazeale reactor celebrated its 50th anniversary Aug. 15 with a rededication of the reactor. All of the former directors that attended were presented with bookends to commemorate this milestone.

Over 200 people attended the day's events.

"It was good to see so many former students and researchers return," said Adina LaFrance (junior- nuclear engineering). "We were able to show that the field is still here and alive and well."

The reactor has been upgraded multiple times throughout its history, Sears said. In 1965, a TRIGA (Training, Research and Isotope Production reactor by General Atomics) reactor core was installed to increase the power from 200 kilowatts to 1,000 kilowatts at steady-state and 2,000 megawatt pulsing capability.

Another key addition was made in 1994, when the bridge, from which the core is suspended, was modified to allow "east and west, and rotational movement, along with the north-south movement that was part of the original design," Sears added.

Sears said when most people think about a nuclear reactor, they think of the large power plants that provide electricity. He added that those reactors are mostly interested in the heat that is released during a nuclear reaction. They use the heated water to power turbines, which in turn operate the generators to create power.

Penn State's reactor is often referred to as a "research reactor" because it studies the data collected from the neutrons that are released during a nuclear reaction, Sears said. The Breazeale reactor uses the neutrons that are emitted to expose samples to radiation for laboratory experiments, and for neutron activation analysis and neutron radioscopy (real-time viewing) and radiology (film).

Sears said neutron activation analysis is used to accurately determine the concentrations of different elements in the sample that is being studied while neutron radioscopy works similarly to an X-ray and allows researchers to view what is going on inside an object. However, the gamma rays will allow researchers to look through materials, such as lead, that can not be penetrated by X-rays.

"It allows us to see through objects just like Superman, only we can see better," Sears said.

Researchers use control rods, located in the core, to control the speed of the reaction, said Sears, where the reactor is located.

The core is shielded by 71,000 gallons of water. The 24-foot-deep tank is filled with "ultra-pure" water, which will not conduct electricity.

"There are regular 100-watt flood lights attached to the frame," Sears said. "And the electrical current that powers them is exposed to the pool."

When researchers cause the core to pulse, the amount of given-off power skyrockets.

In 300 milliseconds, the core jumped from 100 watts to 276.5 megawatts. The temperature of the core rose from 26 degrees Celsius to 299 degrees Celsius during the same time period.

The core, which is cooled by the natural circulation of water, heats up so quickly that there is no time to transfer the heat away from the core, Sears said.

Danielle Hauck (graduate-nuclear engineering) is using neutron activation analysis to study the increased gold intake in tree rings during periods of volcanic activity.

The excess sulfur in the air during an eruption leads to the trees absorbing excess nutrients, she said.

"The trees take up gold because it is chemically similar to copper," she added.

She is currently studying tree rings from the past 500 years, she said, because there is recorded data on volcanic eruptions for that time period. Once there is a better understanding of how the nutrients correlate to the eruptions, she will move on to older tree rings, the oldest of which are dated back to 7,000 B.C.

"Neutron radiology allowed us to see how water and air flow inside of a pipe," Sears said, "which was originally only theoretical."

While the reactor does not produce electricity for the campus, the facility is used for research, education, and service, Sears said.

"The reactor was used in the restoration of the Hewer statue inside Eisenhower Auditorium," Sears said. "The anatomically correct statue had a fig leaf, and it was unsure if it was part of the original design. A sample was taken from the leaf, and it was determined that the fig leaf was added later."