Oak Ridge: Y-12 Pilot Plant (Building 9731) Virtual Tour

An up-close color photo of several 1940s-era dials and knobs on a metal wall.
Explore the interior of Building 9731 at Y-12 in Oak Ridge.



Go behind-the-fence on a virtual tour of the Y-12 Pilot Plant (Building 9731) at the Y-12 National Security Complex in Oak Ridge, Tennessee. Explore the interior of the building where the Calutron Girls trained to separate uranium-235 from uranium-238. This enriched uranium was used in Little Boy, the atomic bomb dropped on Hiroshima, Japan on August 6, 1945.

While part of Manhattan Project National Historical Park, Building 9731 is located within the highly secured grounds of Y-12. No in-person visitation is currently available. Take our virtual guided tour to explore Building 9731.

Ways to Explore

Start the Tour: Begin the tour by selecting the play icon in the middle of the first image below. When the tour opens, click on the white circles to choose your path. Click on hotspots, the white “i” icons of your choice, to access informative text and images.

Audio Described Video Walkthrough: Watch the audio described video walkthrough tour by selecting the play icon in the middle of the second image.

Panoramic Tour: Explore a series of panoramic images and historic and modern photos of Building 9731. 

Text and Image Descriptions: There are five hotspots in the virtual tour with text and photos. Below is the text and image descriptions for each of the virtual tour hotspots. Browse through all the hotspot titles or jump straight to a hotspot that interests you. 


Audio Described Video Walkthrough


Open Transcript 


In a building the size of a warehouse, polished concrete floors reflect florescent lights hanging from an approximately 20-foot (or 6-meter) high ceiling. Celadon green rectangular support columns stand perpendicular to pipes, cables, ducting, and exposed metal beams overhead.

A visitor walkway extends toward our 11 o’clock position, demarcated by white lines painted approximately six feet (or 1.8 meters) apart.

To the right of the walkway, in the center of the space, a metal workbench and table stand above a cluster of approximately two-foot (or .6-meter) tall, metallic canisters shaped like antique milk cans.  A welcome poster with the heading, “Y-12 sits on an easel, with indistinct gray images surrounding a document. On the column behind the poster, a black and white sign reads: “Notice: Safety Glasses Must Be Worn In This Area.”

On the far right, a self-contained, one-story room features brown wood paneling within metal frames, a square window, and a closed wooden door with a rectangular window.

On the far left of the space, an open doorway reveals a meeting room with rows of black chairs.  Outside the room to the right, a table displays various objects, including a vintage time-punch machine.  Above the table, a colorful recruitment poster depicts a man in a blue hat and uniform glancing over his shoulder toward us and pointing his thumb toward himself. Large text reads: “Who Me? Yes You… Keep MUM About This Job.”

Moving along the walkway toward our 11 o’clock position, another “Y-12” poster stands on an easel to the left of a long table draped with a blue, floor-length, pleated tablecloth.  The table supports a glass display case featuring various historic objects of metal and wood.

Ahead, sunlight streams through a row of horizontal windows near the ceiling, illuminating two heavy-machinery workstations.

To the right of the walkway, a third Y-12 poster stands in front of a bulky blue-gray metal machine.

Moving forward, the walkway right, flanked by machinery on either side.  On the left, a six-foot (or 1.8-meter) high dark rust colored metallic cylinder stands on a four-wheeled rectangular base.  On the right, three metal steps bordered by bright yellow railings lead up to the lower of two blue platforms amid various equipment.

Turning ninety degrees to the left, the walkway branches toward the alpha calutrons - a towering, rectangular, steel blue metallic structure with various narrow rectangular protrusions.  On its right, atop a four-wheeled base, a cylindrical piece of equipment features stacks of horizontal slots behind vertical metal bars.

With the machinery on our right, the walkway passes additional “Y-12” displays on our left, each with a vintage, labeled photo, a drawing, and a year—including “1943” and “1944”.

Stepping forward, a perimeter wall ahead features tall, glass-block windows set in concrete blocks, painted celadon green. Turning ninety degrees to the right at the window, dozens of slender white ropes dangle from equipment boxes overhead. A narrow passageway is visible ahead, but the path does not continue there.

Turning ninety degrees right once more, with the glass-block window behind us, two cabinet-sized metal boxes stand behind the dangling ropes on our left.  Across from them, with the towering rectangular structure now on our right, a thin, gray metal desk holds a vintage telephone.

Just overhead, half a dozen exposed pipes run parallel to the walkway.

Moving forward along the walkway, the machines surrounded by the blue platforms with yellow railings now stand at our one o’clock position.  In front of the nearest platform, a sealed, gray metal glove box stands approximately 4 feet (or 1.2 meters) tall.  On its left side it features two sets of twin cylindrical openings, each with a black sleeve dangling from it.  On the adjacent side facing us, two larger, cylindrical protrusions each bear the marking, "33”.

A closed spring green door with a square window is to the left of the path.

Moving forward, past the glove box and equipment platforms, another glass display case on a blue skirted tablecloth features objects displayed in hinged, rectangular cases.  Atop the glass, another “Y-12” poster leans against the celadon green wall bordering the walkway on our left. Two framed black and white photos hang on the wall above the case.

To our right, a wooden rack and two metal carts hold sections of metallic missiles.  Further to the right, another cloth-draped table holding a glass display case lines an adjacent light blue wall hung with black-and-white images in frames.

Down the path beyond the missiles, at our one o’clock position, a refrigerator-sized tan piece of equipment stands just to the right of the painted walkway. Behind it, to our right, the beta calutrons - another towering, steel blue metal, roughly-rectangular structure featuring a profusion of panels and vertical pipes.

Moving forward, past another closed spring green door, sunlight filters through another glass-block window straight ahead.  Just to its right, a rolling gray metal service door stands closed.  Framed black-and-white images hang from a wall on our left, and between the window and service door.  In front of the window, a six-foot-long (or 1.8 meters long), army green cylindrical container rests on a rolling rack.

To the right of the walkway, two parallel flights of six steps descend below the floor level into a sunken, rectangular, concrete area surrounding the towering metal structure, now on our right.

Turning 90 degrees to the right and moving along the walkway, with the service door now on our left, a bright-red door straight ahead reads, “Exit” and “Fire Door – Keep Closed”.  A wall-mounted fire extinguisher sits low just to the right of the door.  To its right, an eight-foot (or 2.4-meter) high “Y-12” purple display panel features paragraphs of text, half a dozen photographs, and the heading, “The Core of the Manhattan Project”.

Pivoting ninety degrees, with the service door behind us and the fire door on our left, the lined walkway ends at a cream-colored section of floor. Three blue-skirted display tables, interspersed with smaller Y-12 display posters, frame a rectangular area at our 11 o’clock position.  Straight ahead, metal railings surround the sunken access area, with red paint lining the brim of the concrete walls just above the floor.  Punctuating the red paint, strips of yellow mark the top of each stairway leading down toward the towering metal structure.





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8 minutes, 17 seconds

An audio described walkthrough of Building 9731 at the Y-12 Plant in Oak Ridge, TN.


Hotspot Text & Photo Descriptions

There are five hotspots in the virtual tour with text and photos. Below is the text and image descriptions for each of the virtual tour hotspots. Browse through all the hotspot titles or jump straight to a hotspot that interests you.  

Last updated: February 15, 2024

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Contact Info

Mailing Address:

Manhattan Project National Historical Park
c/o NPS Intermountain Regional Office
P.O. Box 25287

Denver, CO 80225-0287


Hanford: 509.376.1647
Los Alamos: 505.661.6277
Oak Ridge: 865.482.1942

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