Highlights of Y-12’s History

View highlights by decade since Y‑12's initial planning and wartime mission starting in 1942 through its current missions today. Click a decade below to show its highlights. Click again to hide.

Y-12 History

An era of intense activity that included construction of Y‑12, completion of its World War II mission of separating the uranium 235 for Little Boy — the first atomic bomb ever used in warfare, and the start of its new mission of manufacturing uranium components for nuclear weapons.

1942 September — Decision to building Electromagnetic Separation Plant (Y‑12) in East Tennessee
December — Specific site selected
1943 February 1 — Ground broken for Y‑12
February 18 — First building started (9201-1)
March — Building 9731 Pilot Plant was first building completed
March — 14,700 tons of silver borrowed to wind coils of Calutron magnets
August — Building 9201-1 (Alpha 1) completed
September — First alpha track of Calutrons finished
October — Building 9201-2 (Alpha 2) completed
November — Building 9201-3 (Alpha 3) completed
November — Building 9204-2 (Beta 2 completed
December — Major start up problems with alpha track
1944 January — Second alpha track of Calutrons started operation
March — First Uranium 235 separated, processed and shipped to Los Alamos
May — Building 9201-5 (Alpha 5) completed
October — Building 9201-4 (Alpha 4) completed
November — Building 9204-1 (Beta 1) completed
1945 March — Building 9204-3 (Beta 3) completed
July — Building 9204-4 (Beta 4) completed
July/August — About 22,000 people were working at Y‑12
August 6 — Uranium-235 electromagnetically separated by the Y‑12 plant is used in Little Boy, the atomic bomb dropped on Hiroshima, Japan
1946 August — Y‑12 produces first stable isotopes—the genesis of the medical isotope program
December — All calutrons shut down except those in Building 9731 and Beta 3
1947 April — Staff reduced to less than 3,000
July — Uranium from K-25 reduced to metal and uranium machining technology brought from Los Alamos to Y‑12 to begin Y‑12's next major mission of manufacturing uranium components for nuclear weapons.
1948 March — First nuclear weapons parts manufactured at Y‑12
1949 March 19 — The gates to the “Secret City” open — Y‑12 is still not on any maps

A decade of increased activity, new missions and tremendous growth in stature. Zirconium separation, lithium separation and manufacturing components for thermonuclear weapons testing and deployment dominated the scene described by Alex Zucker as a “heady time” at Y‑12.

1950 January — Hydrogen bomb development announced by President Truman
Large-scale precision machining of beryllium at Y‑12
Hafnium separated from zirconium to produce pure zirconium for cladding nuclear reactor fuel
March — Beta 3 used for experiments with cyclotrons and separation of stable isotopes by Oak Ridge National Laboratory
1951 ELEX (electrical) process developed for separating lithium 6
Nitrogen experiment in 63-in. Cyclotron in Beta 3 proves H‑bomb would not ignite the atmosphere
1952 Experiments began using 86-in. Cyclotron in Alpha 2
OREX (organic) process attempted to separate lithium 6
October — First thermonuclear device tested
1953 ELEX process placed in production in Beta 4 with 50,000 stirring motors
October — First lithium hydride parts machined at Y‑12
November — First thermonuclear device test parts produced and assembled at Y‑12
1954 October — The first batch of thermonuclear parts is assembled and shipped from Y‑12
1955 COLEX processes installed in Alpha 4 and Alpha 5 to separate lithium 6
Mercury spills occurred between 1953 and 1963 that entered East Fork Poplar Creek
1957 Improved uranium purification system designed and installed
1958 7,500-ton press installed
1959 COLEX process in Alpha 5 is shut down because Alpha 4 is meeting all production demands

A time of expansion and steady improvements in machining capabilities brought Y‑12 to the forefront of precision machining and measurement. Computerization and major breakthroughs such as the numerical controlled machines with air-bearing spindles and diamond cutting tools are seen across the site.

1960 First numerically controlled machine installed at Y‑12
1961 Y‑12 formally recognized as having best precision machining facilities and capability in nation
1962 Superfine machining era begins at Y‑12 using diamond cutting tools, interferometers and air bearing spindles — a Y‑12 invention that enabled highly precise machining where “1/10th” is commonly understood to mean “1/10,000th” of an inch.
1963 COLEX process shut down in Alpha 4
1964 The air-bearing spindle is installed on a production tape-controlled turning machine
1966 The air-bearing spindle proves to be a major machining technology breakthrough and the technology is transferred to private industry
1967 Y‑12 produces the NASA “moon boxes” to bring back lunar-surface geological samples to Earth
Y‑12 holds first open house in Building 9737 in conjunction with Oak Ridge's 25th birthday celebration

Y‑12 awakens to the realities of environmental requirements as necessary prerequisites to doing the mission and renewal of 30-year-old infrastructure. Missions continue to expand and Y‑12’s vital contribution to fighting the Cold War is well established.

1970 Environmental concerns of asbestos, PCBs, lead paint, etc., have significant impact on Y‑12 operations
Last of 14,700 tons of silver borrowed from U. S. Treasury is returned when the magnets in Building 9731 are converted from silver windings to copper
1972 Y‑12 begins “stockpile surveillance” disassembly to study effects of aging in nuclear weapons
1974 AEC is changed to Energy Research and Development Administration and the Nuclear Regulatory Commission
Atomic Vapor Laser Isotope Separation research is begun at Y‑12
Utilities Systems Restoration and Production Capabilities Restoration Programs initiated
1975 Y‑12 facilities are used to store highly enriched uranium that is not in a nuclear weapon
1977 Department of Energy created to replace ERDA

A period of an enormously heavy workload and around-the-clock activities at Y‑12. Some 8,000 people worked feverishly to manufacture as many nuclear weapon secondaries as possible knowing the pressure was on Y‑12 to lead the way toward winning the Cold War. And that was the case when the pace set by Y‑12 workers succeeded in breaking the Soviet Union’s economic back and ending the Cold War.

1982 Major security upgrade at Y‑12
1983 First steps taken to close “S-3 Ponds”
Mercury issue surfaced and congressional hearings held at Oak Ridge's American Museum of Science and Energy
1984 Martin Marietta Energy Systems, Inc. selected to manage DOE's Oak Ridge, Paducah and Portsmouth facilities, including Y‑12
1986 Y‑12 wins special award for having best computer-integrated manufacturing program in nation
1988 Navy work for Seawolf submarine begins
1989 Cold War production led to 8,000 people working around the clock to produce nuclear weapons resulting in the breaking of the Soviet Union's economic back as they attempted to match Y‑12's pace

A decade of radical change from high production to weapons reductions and returns for disassembly. First forays into nuclear weapons nonproliferation when Former Soviet Union countries required assistance to protect nuclear materials. Y‑12’s tremendous technology and skills are taken into every state in the union to assist private industry. Y‑12 becomes a National Prototype Center.

1990 Cold War ends with Soviet Union collapse and Berlin wall opened
1991 First weapons reduction announced by United States
1992 First nuclear weapon disassembled for storage at Y‑12 beginning a new storage mission
1993 Y‑12 celebrates 50th Anniversary
New program of sharing Y‑12 technology and expertise with industry leads to years of assistance provided to private industry in all states across the nation
1994 Y‑12 leads a team that airlifts enriched uranium from Kazakhstan to United States (Project Sapphire)
Surplus highly enriched uranium is placed under international safeguards at Y‑12.
September 23 — Y‑12 is shut down because of conduct of operations concerns — restart required
1997 Y‑12 meets the requirement for an upgraded B61-11 weapons system ahead of schedule
Congress designates Y‑12 the National Prototype Center
1998 The first production unit is met ahead of schedule for the W87 Life Extension Program.

A time of renewed spirit, revitalization and modernization. First new production building in 30 years is completed, new enriched uranium storage building is constructed as the most secure location in the world and two new office buildings put a brand new face on Y‑12.

2000 National Nuclear Security Administration created by Congress
Oak Ridge Y‑12 Plant name changed to Y‑12 National Security Complex
November — BWXT Y‑12 chosen to manage Y‑12
2001 Footprint reduction begins with demolition of Manhattan Project–era wooden buildings
2002 Approval obtained to construct new uranium storage facility
Began Facilities and Infrastructure Recapitalization Program to reduce footprint
2003 Construction begins on the Purification Facility, the first major production facility to be built at Y‑12 in more than 30 years
Y‑12 celebrates 60th anniversary
2004 Construction begins on the Highly Enriched Uranium Materials Facility (HEUMF), the largest design effort at Y‑12 in more than a decade
Nuclear materials and process designs surrendered by Libya are transferred to Y‑12, some of which are displayed at a media event attended by Energy Secretary Spencer Abraham
President Bush inspects Libyan nuclear materials secured in Oak Ridge, and Condoleezza Rice expresses appreciation for Y‑12 support in combating weapons of mass destruction
The W87 life extension program is completed successfully and on schedule
A new storage facility opens for preserving Y‑12 historical records; it employs document protection technologies used in the new Bill Clinton and Dwight D. Eisenhower presidential libraries
December — Approval of “mission need” is obtained for a new Uranium Processing Facility (UPF)
2005 Beta 3 Calutrons opened for public tour for first time ever and over 2,000 people attend guided tours during Secret City Festival
Initial design of the Uranium Processing Facility begins
December — Approval gained to begin construction on private financed facilities at Y-12 — a first for NNSA
2006 Construction halted on HEUMF because of quality concerns
Construction began for two new private-financed facilities, a public interface facility and a main office building
Created initiative for external training provider with Nuclear and Radiological Field Training
2007 March — Y‑12 National Security Complex designated the National Nuclear Security Administration’s Uranium Center of Excellence
July — moved into the New Hope and Jack Case centers which are Y‑12's first private-financed facilities and includes the Y‑12 History Center
July — Approval of UPF Critical Decision – 1 (preliminary baseline)
2008 May — Created first Foreign National Workshop with Kurchatov Institute
Added external training provider initiative program Applied Radiological Techniques
September — HEUMF construction completed
September 29 — Public Tour of HEUMF before security features added
2009 Final touches put on HEUMF and movement of special nuclear material initiated
January 2009 — Added external training provider initiative programs Alarm Response Training program and Chemical Security Academy
April — American Recovery and Reinvestment Act brings $292 million to fund three projects: Remove materials stored in Buildings 9201-5 and 9204-4 and west storage yard; demolish five buildings and a portion of another; and remediate storm sewer lines
Summer — Y‑12 donated two historic railroad tanker cars to Southern Appalachian Railway Museum
Summer — Y‑12 began implementing a wireless communication infrastructure, the first NNSA site to seek approval for using a wireless system
Began initiative to downblend 12 tons of weapons-grade uranium to make 220 tons of low-enriched uranium suitable for nuclear power reactors

As we continue the transformation of Y‑12 after spending a decade demolishing 300 buildings and erecting four new structures, the focus shifts to the construction of the Uranium Processing Facility. The security reputation of Y‑12 is challenged by nuclear weapons protestors. Lessons learned from that event and continued dedication to serving the nation's uranium storage, uranium processing and nonproliferation of nuclear materials remain at the forefront of Y‑12's missions into the 2010s.

2010 March 22 — HEUMF dedicated with over 1,000 visitors in attendance
April 7 — Movement of all special nuclear material stored in Building 9720-5 warehouse to the new HEUMF completed
April 8 — Y‑12 supports operation “Golden Llama,” where highly enriched uranium was removed from Chile; an earthquake hit during the operation forcing the use of an alternate route for removal
Spring — Microwave casting of uranium moves into production
May — Began construction to move Bear Creek Road north from Jack Case Center to entrance to Bear Creek Portal Parking Lot
June 24 — A pair of two million gallon water tanks atop 250 foot towers were placed into service as the primary fire water source for Y-12 replacing the tanks on Chestnut Ridge
Winter — Greg Schaff awarded first Y‑12 Technology Fellow
Winter — RonJohn Blend, a versatile, environmentally safe solvent was invented by Ron Simandl
2011 January — Added external training provider initiative program Applied Radiological Response 2
Completed last dismantlement of W70 Lance warhead
April — completed Bear Creek Road movement north from Jack Case Center to Bear Creek Portal Parking Lot
Initiated the Y‑12 National Uranium Materials Archive in support of the nation's forensic analysis capabilities
First NNSA site to achieve Line Oversight Contractor Assurance System affirmation
Completed six of seven American Recovery and Reinvestment Act projects expected to cost $219 million for a cost of $202 million allowing $17 million to be added scope for ARRA projects in FY 2012
First NNSA site to implement the American Society of Mechanical Engineers NQA-1 quality standard for nuclear facilities
Reached almost 7,000,000 manhours or approximately nine months without a lost-time injury
Winter — Initiated dismantlement of B53 and B83 bombs
Winter — Initiated the Y-12 National Uranium Materials Archive in support of the nation’s forensic analysis capabilities
2012 June — Achieved Star status in the Volunteer Protection Program
Completed all American Recovery and Reinvestment Act projects that included demolishing approximately 84,000 sq. ft.
All legacy materials moved out of Building 9201-5 and the second floor of Building 9204-4 as a part of the American Recovery and Reinvestment Act projects
June — A revised Critical Decision (CD)‐1 submittal was approved for the Uranium Processing Facility project
July 28 — security breach by three nuclear weapons protestors
Jack Case Center was certified as Y-12's first High Performance and Sustainable Building facility
Completed Facilities and Infrastructure Recapitalization Program that demolished 321 facilities reduced the site footprint by 1.4 million square feet and retired $18 million in deferred maintenance backlog — the FIRP accounted for 47 percent of the nuclear security enterprise total square foot reduction goal of 3 million
October — Defense Nuclear Facilities Safety Board public hearing held in Knoxville on Uranium Processing Facility
2013 Integrated more than 500 protective force subcontract personnel into the Y‑12 prime contract in 28 days, strengthening reporting structure and communication
Improved the security infrastructure and Central Alarm Station — driving down false alarm rates, equipment repair times and compensatory measures
Processed and delivered more than 1.2 metric tons of low enriched uranium feedstock for foreign research reactors and downblended 1.1 metric tons of LEU to replenish the inventory for future demand. Y‑12 secured highly enriched uranium from France, Italy and Canada
Validated production microwave as the baseline casting technology
September — Submitted Critical Decision 2 (CD-2) for Uranium Processing Facility
Won a 2013 R&D 100 Award for the high-efficiency, thermal neutron detector
December — Second Defense Nuclear Facilities Safety Board public hearing held in Knoxville to discuss the Uranium Processing Facility construction plans
2014 March–April — Red Team, led by Thom Mason and using two dozen specialists from across the various DOE laboratories formed to evaluate the Uranium Processing Facility design
March — Prison sentences given to three nuclear weapons protestors who breached Y‑12 security on July 28, 2012
March–June — Management and Operating contract transition from B&W Y‑12 to Consolidated Nuclear Security
July 1 — Consolidated Nuclear Security, LLC, assumes Y-12 and Pantex contract
September — Building 9744 demolished in the continuing disposition of legacy facilities at Y-12
2015 January — The Nuclear Facility Risk Reduction project is completed to provide improvements for enriched uranium operations.
May — Received the Critical Decision 0 for a new Lithium Production Capability
July — Opened the newly rerouted Bear Creek Road (paved using pavement recycled from parking lot removal)
July — Began site preparation for the Uranium Production Facility
August — Building 9808 demolished in the continuing disposition of legacy facilities at Y-12
November— The Manhattan Project National Historical Park was established with Building 9731 and Building 9204-3 being included in the park from the Y-12 site and on November 12, a dozen busloads of the public were given tours through both buildings
2016 January — Received the Critical Decision 1 for a new Y-12 Emergency Operations Center
February — W69 canned subassemblies dismantlement completed
April — Received the Critical Decision 0 for the new Y-12 Fire Station
April — Building 9995 $10M infrastructure upgrade completed
May — 2,247 containers of solid residue mixed waste removed two years ahead of schedule
August —Significant work on the Uranium Processing Facility progressed as construction activities began for the Construction Support Building, the concrete batch plant, and the mass excavation for the main buildings of the facility
2017 January — Manhattan Project National Historical Park introduction film unveiled to educate visitors about the history of the site since public access in limited
June — Hundreds of people participated in public tours of Building 9731 during the annual Secret City Festival
July — Critical Decision 1 approved for Fire Station.
August — Delivered the Critical Decision 2/3 Package for the UPF Main Processing Building, Salvage & Accountability Building and the Process Support Facilities to NNSA for their review and approval.
August — Critical Decision 1 approved for the West End Protected Area Reduction project to reduce the size of the protected area by more than 50%
August – Four individuals were named to the Fellows Program: Uranium Fellow Glenn Pfennigwerth, Metallurgy Fellow Alan Moore, and Y-12 Component Analysis/Surveillance Fellow Vincent Lamberti
September — Request for Bids issued for Emergency Operations Center
September — Legacy buildings 9111 and 9112 demolished