The walls and mystery that surround the Y-12 National Security Complex and the Oak Ridge National Laboratory are both enough to intrigue most Knoxville residents.

And for a select few, their curiosity was fed on Aug. 30.

The mysteries of the so-called "Secret City" were revealed to an attentive audience on Friday as Y-12 historian Ray Smith held a lecture in the Baker Center as a part of the Nuclear Security brown bag series.

An expert on the evolution of the Oak Ridge Y-12 National Security Complex, Smith spoke about the plant's development since its inception 70 years ago.

Now known as Y-12, the facility was initially designed to make highly-enriched uranium through the use of Calutrons.

Calutrons – known as California University Cyclotrons – spin the uranium to separate U-238 particles from the closely associated U-235 particles to purify the substance.

Smith illustrated this complicated process in more simplistic terms.

"If I had two rubber bands hanging down from my hand, and I put a golf ball on one, and a ping pong ball on the other, then I held it down on my side and spun it real quick for a half-turn, the golf ball would stretch it further than the ping pong ball. I'd get two arcs," Smith said.

Sparked by a letter from Albert Einstein to President Roosevelt, Smith described the Manhattan Project as an effort to outpace Germany's nuclear aspirations.

With an incentive to work quickly, scientists were forced to learn on the job. Even so, numerous precautions were taken in the material development and plant design at Oak Ridge to protect workers.

Planned with safety in mind, the plants were built between two ridges – Oak Ridge and Pine Ridge – where, if some of the active material exploded, the majority of the blast would be controlled.

The enriched uranium was transported in gold-lined briefcases and covered by cloth as another cautionary measure. Upon later investigation, it was revealed that Alpha radiation given off by moderate quantities of uranium is not harmful.

President Roosevelt's administration poured approximately $480 million into the Manhattan Project.

A massive amount of enriched U-235 – 60 kilograms – was needed to make the warhead nicknamed "Little Boy."

With the help of then-Tennessee Sen. Kenneth McKellar, Oak Ridge was deemed the proper spot due to its burgeoning workforce of 22,000 manual laborers and relatively unknown location.

Since the end of the Cold War, the mission statement of Y-12 has altered. In additon to manufacturing components for all active nuclear weapons, its expand purpose inclides protecting essential nuclear materials not in nuclear weapons, supporting the downgrade of research reactors from higly enriched uranium to much lower enriched urauium and help stopping the spread of necular weapons around the world.

Efforts to continue work has been thwarted by anti-nuclear activists like Megan Rice, a Roman Catholic nun who broke into the Y-12 facility on July 28, 2012, and splashed blood on the highly enriched uranium materials facility.

In an interview with The New York Times, Rice explained the political agenda behind her protest.

"We spend more on nuclear arms than on the departments of education, health, transportation, disaster relief and a number of other government agencies," Rice said.

Looking into the future of Oak Ridge, Smith said that work has started to move a road to make room for constuction of a new national uranium processing plant to be built within the next decade. 

More information on Y-12 can be found here.

Correction:

In the article "Historian offers glimpse into ORNL" printed on Tuesday, Sept. 3, the article should have stated the difference between Y-12 National Security Complex and Oak Ridge National Laboratory. Y-12 is a National Nuclear Security Administration facility within the Department of Energy dealing with nuclear technologies and is managed by B&W Y-12. ORNL is multiprogram research laboratory within the DOE and is managed by UT-Battelle.