Are nuclear weapons still made in Oak Ridge? What Y-12 does for the US | Know Your Knox

There is a common misconception that nuclear weapons parts are no longer made in Oak Ridge: In reality, there would be no nuclear weapons in the U.S. stockpile without the Y-12 National Security Complex.

"We're just one part of what makes a nuclear weapon. It's a very important part, but just one part," Gene Sievers, Y-12 site manager, told Knox News. "The technical answer is no, the nuclear weapon is not made at Y-12, but you can't make a nuclear weapon without Y-12."

Today, Y-12 doesn't enrich uranium or build parts for new nuclear weapons. The U.S. stopped enriching bomb-grade uranium and building new nuclear weapons in 1992. Instead, Y-12 processes and stores uranium and refurbishes or dismantles the uranium components of old warheads in the U.S. stockpile.

The plant was built in 1943 for the Manhattan Project, whose mission was to build the world's first atomic bomb and win World War II. It was the last stop in the enrichment process that produced uranium fuel in Oak Ridge for the bomb dropped on Hiroshima in 1945.

Nuclear weapons were never built from start to finish in Oak Ridge. Y-12's purpose was centered on uranium from the very beginning. It works together with its sister site, Pantex, outside Amarillo, Texas, where nuclear warheads are disassembled and assembled.

While nuclear weapons are not built in their entirety in Oak Ridge, every one of the more than 5,000 bombs and missiles in the U.S. stockpile has parts that were built or maintained at Y-12.

Y-12 is designated as the nation's "Uranium Center of Excellence," and it is also where the U.S. stores the bulk of its bomb-grade uranium. That makes it one of the highest-security weapons facilities in the nation. It sits on an 811-acre footprint in Bear Creek Valley about 20 miles west of Knoxville.

Y-12's work goes beyond weapons. Here's a look at what the facility does and why it remains controversial.

Y-12 has peaceful uranium missions, too

After the Atomic Age dawned frightfully with the deadly bombings of Hiroshima and Nagasaki, scientists across the U.S. began looking for peaceful uses for nuclear technology. Much of that work happened in Oak Ridge and continues today.

Enriched uranium has uses beyond bombs and missiles. Y-12 stewards the U.S. Navy's supply of bomb-grade uranium, which was taken from dismantled nuclear weapons and now powers the nuclear reactors aboard its submarines and aircraft carriers.

At its peak, the U.S. stockpile had over 31,000 nuclear weapons. Today, that number is just over 5,000 after decades of dismantling, though many of the weapons are several times more powerful than the bombs used in World War II.

Y-12 is part of a complex of weapons sites that make sure the remaining bombs and missiles are up-to-date. In 2023, the National Nuclear Security Administration delivered 200 modernized nuclear warheads to the military, according to the agency's annual report.

Y-12 can turn bomb-grade uranium into a safe but powerful fuel for advanced nuclear reactors called high-assay low-enriched uranium through a process called "downblending."

Sievers, the site manager, described Y-12 as a "huge recycling factory" for uranium and lithium, another sensitive and complex material in nuclear weapons. Y-12 is at work on new landmark facilities for each material: a massive Uranium Processing Facility and a Lithium Processing Facility, which broke ground last year.

Y-12 supplies radioactive isotopes for medical applications and trains teams of health care professionals on how to use the materials safely.

Its purpose is also global in reach. Y-12 employees have gone to dozens of countries to decommission bomb-grade uranium and put it into more secure storage to support nonproliferation efforts.

"Those are a very dynamic and growing set of missions and work that we do here at Y-12 and our team is very proud to accomplish that for the nation," Sievers said. "It's the most dynamic time on this footprint since the Manhattan Project."

Y-12 is very different from the neighboring Oak Ridge National Laboratory, also once a Manhattan Project site.

Called "X-10" during the project, the lab was home to the world's first continuously operating nuclear reactor. It never enriched uranium for a bomb, but proved that plutonium could be produced from uranium in a reactor. It is now the nation's largest science and technology lab.

Both Y-12 and ORNL belong to the U.S. Department of Energy, but they are under different department offices and are managed separately. Y-12 is managed by Consolidated Nuclear Security for the National Nuclear Security Administration, and ORNL is managed by UT-Battelle for the Office of Science.

Y-12 still draws ire of peace activists

Y-12 is something like a Rorschach test for the fragile American psyche in a nuclear age.

To the Department of Energy and Y-12's workforce of up to 10,000 people - many of whom come from families that have worked there for generations - the plant is a proud bastion of national security where the U.S. stockpile is nurtured and the destructive aspirations of our most powerful enemies are kept in check.

To its detractors, Y-12 is an inhumane bomb factory that contributed to the deaths of hundreds of thousands of innocent Japanese citizens and continues to push the world closer to the brink of nuclear annihilation. In 2012, three Christian peace activists, including an 82-year-old nun, broke into the facility to advance this message. The trio spent two years in prison for the act.

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Ralph Hutchison, a Presbyterian minister, led protests at Y-12 as coordinator of the Oak Ridge Environmental Peace Alliance for more than 30 years.

He said many people are confused about the weapons work that continues at Y-12 because they think all nuclear weapons work ended in Oak Ridge back in 1992. Knox News reported in 1996 that the plant was still actively engaged in nuclear weapons development.

It doesn't help that Y-12 employees often speak in national security jargon that can obscure the facility's work, he said.

"I think part of the reason people don't know it is because they have been misled," Hutchison told Knox News. "They don't advertise it, for whatever reason. Are they ashamed of it or what? They prefer to talk in euphemisms, so I think it's not easy for people to find that out."

The Oak Ridge Environmental Peace Alliance continues to stage protests and is drumming up support for the Treaty on the Prohibition of Nuclear Weapons, an international agreement ratified by 70 countries. No nuclear weapons states, including the U.S. and Russia, have signed the treaty.

Know Your Knox answers your burning questions about life in Knoxville. Want your question answered? Email knowyourknox@knoxnews.com.

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This article originally appeared on Knoxville News Sentinel: Does Y-12 in Oak Ridge make nuclear weapons? Know Your Knox