Oppenheimer's greatest influence on Oak Ridge can't be seen today. Here's why

Some of J. Robert Oppenheimer's influence on Oak Ridge is visible today and some is invisible.

One of the most famous images of Oppenheimer, the theoretical physicist who oversaw the production of the first atomic bomb during the secret Manhattan Project, was taken in 1946 at the Guest House in Oak Ridge, now an assisted living facility called the Alexander Guest House.

In the photo, Oppenheimer looks relaxed, with a cigarette held loosely in his hand and a winsome look on his face. The bombs he developed had unleashed the seismic final crack of World War II, but his battle against the U.S. government to contain nuclear warheads had not yet begun.

D. Ray Smith, historian for the city of Oak Ridge, printed the photo out and placed it on the same mantel that appears behind Oppenheimer in the photo.

It was taken during one of several visits Oppenheimer made to what was then called the Y-12 Electromagnetic Separation Plant and other facilities, though Smith said the exact number of visits is unknown.

"Oppenheimer knew very much about what was going on in Oak Ridge," Smith said. "He needed the uranium that was being produced here."

Oak Ridge was built in 1942 to support the Manhattan Project by creating the enriched uranium that would fuel Little Boy, the bomb dropped on Hiroshima and the first nuclear weapon ever used in warfare. The uranium isotope, uranium-235, is a fissile material, meaning it could sustain a nuclear chain reaction within the bomb.

Eighty years later, as movie fans await the highly anticipated release of Christopher Nolan's sprawling biopic "Oppenheimer" on July 21, interest in Oak Ridge's connection to the scientist has increased as well.

Oppenheimer's connection to Oak Ridge is mostly indirect, since he oversaw the production of the bombs at Los Alamos National Laboratory in New Mexico.

According to Smith, Oppenheimer is respected by Oak Ridgers for his influence in keeping the secret town as part of the atomic bomb effort. However, Smith said the single largest influence Oppenheimer had on Oak Ridge is rarely mentioned.

That's because the S-50 thermal diffusion plant that he encouraged the government to build along the Clinch River was deactivated in 1946 and torn down only a few years later.

One day before the film's worldwide release, the city of Oak Ridge hosted a special screening of "Oppenheimer" on July 20. Tickets sold out as locals flocked to see "the story of the man behind the Manhattan Project, the most important thing to ever happen in the history of the world," according to the Explore Oak Ridge website.

What was Oppenheimer's biggest influence on Oak Ridge?

The Manhattan Project was remarkable not only for its scientific breakthroughs and its secrecy, but also its speed.

In 1938, German chemists discovered that it was possible to split a heavy atom in a process called nuclear fission. A year later, a letter written by physicist Leo Szilard and signed by Albert Einstein warned President Franklin Roosevelt of the potential threat of a powerful new kind of bomb.

World War II broke out only a month later, when Nazi Germany invaded Poland on Sept. 1, 1939. The Manhattan Project began in earnest after the U.S. entered the war following the attack on Pearl Harbor.

As Niels Bohr, the physicist who developed the modern understanding of the atom, said of the U.S.'s ambitious project, "It couldn’t be done without turning the whole country into a factory.”

Indeed, three sites, one at Los Alamos, one in Hanford, Washington, and one in Oak Ridge, were turned into factories for enriched uranium production and nuclear weapons.

"Oak Ridge was in a race to build an atomic bomb before Nazi Germany. It's that simple. They did whatever they could do to accelerate that timeline," said David Keim, director of communications at Oak Ridge National Laboratory.

The area was selected for the project in 1942 because of its access to TVA's electrical power from Norris Dam and its status as a rural farming community. The U.S. government bought 60,000 acres, moved residents off the land, and broke ground on the Y-12 complex and the X-10 Graphite Reactor in February 1943. The X-10 site is where ORNL now sits.

The concern for speed meant that military leaders and scientists, like Oppenheimer, who was tapped to lead Los Alamos in 1942, and the Manhattan Project's director, Major General Leslie Groves, were willing to try any method to produce enriched uranium quickly.

The known methods were implemented at Y-12, the X-10 reactor, which ceased operations in 1963, and K-25 plant, for which the main plant has been demolished and the K-25 History Center now tells its story.

By early 1944, Oppenheimer had heard of a new method of enriching uranium the Navy was testing, called liquid thermal diffusion. According to Smith, Oppenheimer pushed Groves to build a plant in Oak Ridge that could serve as a critical first step in the enrichment process before the uranium went to K-25 and Y-12.

Because a large steam plant already powered K-25 along the Clinch River, it was an ideal spot for the new S-50 plant. But it needed to be built fast – 90 days fast.

Ultimately, the S-50 plant was built in just 69 days, according to the National Park Service, highlighting the project's rapid pace. It also reflected Oppenheimer's belief that Oak Ridge was central to the success of the project.

The S-50 plant proved to be costly and less efficient than K-25, and it ceased production in 1946. The plant was demolished in the late 1940s and the NPS says that "access to the original location is difficult and visitation is not advised."

Apart from the S-50 plant, Oppenheimer's influence also was felt because of the presence of his brother Frank, whom he sent to Oak Ridge to oversee operations at Y-12 in 1944 and 1945.

Legacy of Manhattan Project lives on at ORNL and Y-12

Today, the Y-12 National Security Complex and Oak Ridge National Laboratory operate separately. Y-12 is a manufacturing facility managed by Consolidated Nuclear Security for the Department of Energy's National Nuclear Security Administration.

ORNL is a research laboratory managed by UT-Battelle for the Department of Energy. Its research has led to breakthroughs in medicine, advanced materials and climate science.

Though ORNL was established as part of the Manhattan Project, the lab does not work in weapons development. The legacy of innovation has stayed with ORNL, where many of the nation's first nuclear scientists were trained, according to Keim.

"It was the dawn of the atomic age, so someone had to train the scientists and engineers that were trying to figure out how to use this new knowledge for good," Keim said. "We continue to do work in nuclear energy, in fission, as well as fusion."

Daniel Dassow is a reporting intern focusing on trending and business news. Phone 423-637-0878. Email daniel.dassow@knoxnews.com.

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This article originally appeared on Knoxville News Sentinel: Oppenheimer visited Oak Ridge in World War II Manhattan Project