NNSA Timeline | National Nuclear Security Administration

President Roosevelt approves production of the atomic bomb following receipt of a National Academy of Sciences report determining that a bomb is feasible.

President Roosevelt instructs the Army to take responsibility for construction of atomic weapons complex. The Army delegates the task to the Corps of Engineers, which establishes the Manhattan Engineer District.

Brigadier General Leslie R. Groves, head of the Manhattan Engineer District, selects Oak Ridge, Tennessee, site for facilities to produce nuclear materials. Isotope separation of uranium235 takes place in the gaseous diffusion plant built in the K-25 area of the site, in the electromagnetic plant in the Y-12...

Groves selects Los Alamos, New Mexico, as site for separate scientific laboratory to design an atomic bomb.

The first nuclear sub was launched in 1954 on the Thames River. Above, the U.S.S. Nautilus in front of the New York City skyline.

Metallurgical Laboratory scientists led by Enrico Fermi achieve the first self-sustained nuclear chain reaction in pile constructed under the west grandstand at Stagg field in Chicago.

Groves selects Hanford, Washington, as site for full-scale plutonium production and separation facilities. Three reactors--B, D, and F--are built.

Los Alamos scientists successfully test a plutonium implosion bomb in the Trinity shot at Alamogordo, New Mexico.

The gun model uranium bomb, called Little Boy, is dropped on Hiroshima, Japan.

The implosion model plutonium bomb, called Fat Man, is dropped on Nagasaki, Japan. Five days later, Japan surrenders.

Bernard Baruch presents the American plan for international control of atomic research to the United Nations. The Soviet Union opposes the plan, rendering it useless.

President Truman signs the Atomic Energy Act of 1946, leading to the creation of the Atomic Energy Commission.

In accordance with the Atomic Energy Act of 1946, all atomic energy activities are transferred to the newly created Atomic Energy Commission.

President Truman instructs the Atomic Energy Commission to expedite development of a thermonuclear weapon.

President Truman approves a $1.4 billion expansion of Atomic Energy Commission facilities to produce uranium and plutonium for nuclear weapons.

The Experimental Breeder Reactor No. 1 located at the National Reactor Testing Station near Arco, Idaho, produces the first electric power from a nuclear reactor.

The Atomic Energy Commission detonates the first thermonuclear device, code-named "Mike," at Enewetak Atoll in the Pacific. The device explodes with a yield of 10.4 megatons.

President Eisenhower delivers his "Atoms for Peace" before the United Nations and proposes an international agency to promote peaceful applications of nuclear energy.

President Eisenhower announces a moratorium on nuclear weapons testing to begin on October 31, 1958.

The Soviet Union breaks the nuclear test moratorium and the United States resumes testing.

As part of the Plowshare program seeking to develop peaceful uses for nuclear explosives, the Atomic Energy Commission conducts the Sedan test at the Nevada Test Site.

Reconnaissance reveals Soviet missiles in Cuba. The United States blockades Cuba for 13 days until the Soviet Union agrees to remove its missiles.

The United States, Great Britain, and the Soviet Union sign the Limited Test Ban Treaty prohibiting underwater, atmospheric, and outer space nuclear tests. Nuclear testing continues underground.

The United States, Great Britain, the Soviet Union, and forty-five other nations sign the Treaty for the Nonproliferation of Nuclear Weapons.

President Ford signs the Energy Reorganization Act of 1974. The Atomic Energy Commission is abolished. The Energy Research and Development Administration, Nuclear Regulatory Commission, and Energy Resources Council are established.

President Ford appoints Frank Zarb to be the first Administrator of the newly created Federal Energy Agency.

The Energy Research and Development Administration is activated. The new agency is given responsibility for the Atomic Energy Commission's nuclear weapons program. President Ford appoints Robert C. Seamans, Jr., as Administrator.

John F. O'Leary is named Administrator, Federal Energy Administration. Administrator O'Leary previously served as the administrator of the Energy Resources Board of the State of New Mexico.

President Carter announces National Energy Plan in his first major energy speech. His plan calls for the establishment of an energy department.

President Carter signs the Department of Energy Organization Act. The Federal Energy Administration and Energy Research and Development Administration are abolished. James R. Schlesinger is sworn in as first Secretary of Energy. The DOE brings together a score of organizational entities from a dozen...

Charles W. Duncan, Jr., is sworn in as second Secretary of Energy.

James B. Edwards is sworn in as third Secretary of Energy.

The Reagan Administration announces a nuclear energy policy that anticipates the establishment of a facility for the storage of high-level radioactive waste and lifts the ban on commercial reprocessing of nuclear fuel.

Donald Paul Hodel is sworn in as fourth Secretary of Energy.

President Reagan signs the Nuclear Waste Policy Act of 1982, the Nation's first comprehensive nuclear waste legislation.

John S. Herrington is sworn in as fifth Secretary of Energy.

A catastrophic nuclear accident occurs at Chernobyl Reactor #4 in the then Soviet Republic of Ukraine.

Secretary Herrington leads U.S. delegation to Special Session of the International Atomic Energy Agency General Conference in Vienna, Austria, to discuss measures to strengthen international cooperation in nuclear safety and radiological protection in aftermath of Chernobyl.

White House releases "2010 Report," projecting requirements for maintaining and modernizing the nuclear weapon production complex through the year 2010.

James D. Watkins is sworn in as sixth Secretary of Energy.

President Bush signs the Strategic Arms Reduction Treaty (START), which will reduce nuclear weapon stockpiles to 6,000 "accountable" warheads.

Secretary Watkins testifies before the Senate Armed Services Committee that for the first time since 1945 the United States is not building any nuclear weapons.

The United States conducts its last underground nuclear weapons test. Congress imposes a temporary moratorium on nuclear weapons testing.

Hazel R. O'Leary is sworn in as seventh Secretary of Energy. She is the first and only female Secretary of Energy in the history of the department.

President Clinton extends the nuclear weapons testing moratorium for at least 15 months.

Federico F. Pena is sworn in as eighth Secretary of Energy.

Secretary Pena participates in the ground breaking ceremony for the National Ignition Facility, a centerpiece of the stockpile stewardship program, at the Lawrence Livermore National Laboratory.

The Plutonium Uranium Extraction Facility (PUREX), the largest of the Nation's Cold War plutonium processing plants, is deactivated a year ahead of schedule.

The first "subcritical" physics experiment at the Nevada Test Site, code-name "Rebound," provides scientific data on the behavior of plutonium without underground nuclear-weapons testing.

The Department of Energy announces that it will dispose of defense-generated transuranic waste at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico.

Crew members of the U.S.S. Enterprise, the first nuclear-powered aircraft carrier, spell out NR-50! To commemorate the 50th anniversary of the Nuclear Navy. Admiral Hyman G. Rickover formed the Nuclear Power Branch within the Navy’s Bureau of Ships in August 1948. The Office of Naval Reactors is an integrated...

Bill Richardson is sworn in as ninth Secretary of Energy. He makes history while briefly serving in two cabinet posts at once -- both as Secretary of Energy and U. S. ambassador for the United Nations -- for several weeks.

After more than two decades of political, legal, and bureaucratic delays, the first truckload of radioactive waste from Los Alamos National Laboratory arrives at the DOE Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico, 26 miles east of Carlsbad.

Secretary Richardson dedicates the National Ignition Facility target chamber at DOE's Lawrence Livermore National Laboratory.

The Senate votes 48-51 to reject the Comprehensive Test Ban Treaty.

The Department activates the National Nuclear Security Administration (NNSA), meeting the statutory deadline established by the FY 2000 defense authorization act. NNSA's mission is to carry out the national security responsibilities of the Department of Energy, including maintenance of a safe, secure, and...

After two years of negotiations, Vice President Gore and Russian Prime Minister Mikhail Kasyanov sign an agreement to dispose of 68 metric tons (34 metric tons for each country) of weapons grade plutonium. Under the agreement, the surplus plutonium will be irradiated in nuclear reactors or by immobilizing it...

George W. Bush becomes the 43rd president of the United States. Secretary of Energy-designate Spencer Abraham and six other cabinet nominees are confirmed as a group by the Senate in one voice vote. Following the Inaugural Parade, Spencer Abraham is sworn in as the tenth Secretary of Energy.

Secretary Abraham announced that DOE will dispose of 34 metric tons of surplus weapons grade plutonium by turning the material into mixed oxide fuel (MOX) for use in nuclear reactors. The decision follows an exhaustive Administration review of non-proliferation programs, including alternative technologies to...

President Bush and President Vladimir Putin of Russia signed agreement to reduce each country's nuclear arsenal to between 1,700 and 2,200 warhead. "Each country," the agreement states, "shall determine for itself the composition and structure of its strategic offensive arms." The two leaders also agreed to...

The Los Alamos National Laboratory conducts Watusi, a spectacular high-explosives experiment with a yield equivalent to about 37,000 pounds of TNT, at the Nevada Test Site’s Big Explosive Experimental Facility (BEEF). The experiment seeks to demonstrate that existing seismic and infrasound sensors at the test...

The Department of Energy marked the 25th anniversary of its establishment in 1977.

The National Nuclear Security Administration (NNSA) implemented a new organizational structure that eliminates a layer of management and seeks to achieve a 20 percent reduction in federal personnel by the end of Fiscal Year 2004. Three operations offices—at Oakland, Las Vegas, and Albuquerque—were eliminated,...

NNSA’s Los Alamos National Laboratory (LANL) announced that it has successfully made the first nuclear weapons “pit” in 14 years that meets specifications for use in the U.S. stockpile. The plutonium pit, called Qual-1 because it was built with and fully met qualified processes, is for the W88 warhead, which...

Secretary Abraham administers the oath of office to Ambassador Linton F. Brooks to be administrator of DOE’s National Nuclear Security Administration and under secretary of energy for nuclear security. Brooks has held both positions in an acting capacity since July 2002.

The National Nuclear Security Administration’s Lawrence Livermore National Laboratory (LLNL) successfully executes the first plutonium shot using the Joint Actinide Shock Physics Experimental Research (JASPER) gas gun at NNSA's Nevada Test Site. LLNL scientists use the 100-foot, two-stage gas gun to fire a...

NNSA's Administrator Linton Brooks announces the establishment of the Nuclear Radiological Threat Reduction Task Force (NRTRTF) to combat the threats posed by radiological dispersion devices or “dirty bombs.”

The Nuclear Security Administration's Pantex facility outside Amarillo, Texas, dismantles the last nuclear artillery shell, the W-79, in the U.S. nuclear stockpile. “This administration is committed to reducing the threat of nuclear weapons world wide,” says Secretary Abraham. “We have completed dismantlement...

Secretary Abraham, in a speech to delegates at the International Energy Agency in Vienna, Austria, launches the Global Threat Reduction Initiative (GTRI), a comprehensive effort to secure and remove high-risk nuclear and radiological materials that continue to pose a threat to the U.S. and the international...

The National Nuclear Security Administration's reached an important milestone in its efforts to dispose of surplus weapons-usable material as the 100th shipment of low enriched uranium (LEU) departed the Savannah River Site (SRS) in South Carolina for Nuclear Fuels Services in Erwin, Tennessee, four months...

NNSA announced the successful completion at the Pantex Plant outside of Amarillo, Texas, of efforts to refurbish the W87 nuclear warhead and extend its life by 30 years. This marks the end of the first leg of NNSA’s program to ensure that the nation's aging nuclear weapons stockpile is capable of meeting...

The National Nuclear Security Administration (NNSA) commemorated ten years of work securing nuclear and radiological material in Russia and the former Soviet Union by completing security upgrades at two Russian nuclear facilities. Upgrades at a third facility were completed in September. The completion of...

Samuel Bodman is sworn in as the eleventh Secretary of Energy.

President Putin and President Bush agreed to pursue an initiative on nuclear security cooperation at a February 2005 summit in Bratislava, Slovak Republic. This agreement includes for the first time a comprehensive joint action plan for the cooperation on security upgrades of Russian nuclear facilities at...

NNSA's plutonium disposition program moved another step forward with the start of site preparation for its Mixed Oxide (MOX) Fuel Fabrication Facility at the Savannah River Site. NNSA Administrator Linton F. Brooks and U.S. Senator Lindsey Graham led a group of U.S. and Russian dignitaries in turning the first...

NNSA Administrator Amb. Brooks announced that the last W56 nuclear warhead has been dismantled. The 1960s era system has been safely and securely taken apart and will never again be a part of the U.S. nuclear weapons stockpile.

NNSA completed a six-year effort to deliver the first refurbished B61 nuclear bomb. This program will extend the life of the B61 Mod-7 and Mod-11 strategic bombs in the U.S. nuclear weapons stockpile.

The Department of Homeland Security and the DOE/NNSA announced the first phase of the Secure Freight Initiative, an unprecedented effort to build upon existing port security measures by enhancing the federal government’s ability to scan containers for nuclear and radiological materials overseas and to better...

Continuing its efforts to reduce the size of the U.S. nuclear weapons stockpile, the National Nuclear Security Administration announced that uranium components from two major nuclear weapons systems formerly deployed on U.S. Air Force missiles and aircraft have been dismantled at the Y-12 National Security...

NNSA announced the kickoff of the Next Generation Safeguards Initiative (NGSI), which will promote the strengthening of nuclear safeguards worldwide to help ensure the safe, secure and peaceful implementation of civil nuclear energy programs. NGSI will leverage NNSA’s technical assets and international...

The final refurbished B61 strategic nuclear bomb has entered into the U.S. nuclear weapons stockpile, completing an eight-year effort. This program extended beyond their original intended life both the B61 mod 7 and mod 11 strategic bombs, and was completed almost one year early.

Steven Chu is sworn in as the twelfth Secretary of Energy.

The first refurbished W76 nuclear warhead has been accepted into the U.S. nuclear weapon stockpile by the Navy. This culminates a ten year effort to ensure that the aging warhead, already years beyond its original intended life, can continue to be a reliable part of the U.S. nuclear deterrent.

President Obama in a landmark speech in Prague, Czech Republic called nuclear weapons the gravest threat to international security and advocates for the global abolition of nuclear weapons.

On September 24, 2009, President Obama chaired an historic meeting of the United Nations Security Council (UNSC), during which the UNSC unanimously cosponsored and adopted a resolution aimed at implementing the nuclear security agenda President Obama outlined in his Prague speech.

President Obama hosts a Global Nuclear Security Summit to facilitate discussion on the nature of the nuclear threat and develop steps that can be taken together to secure vulnerable materials, combat nuclear smuggling and deter, detect, and disrupt attempts at nuclear terrorism.