7

(Arms Control and Disarmament)

1945 -- July 16-October 3, 1952
FIRST NUCLEAR TESTS

The United States conducts the world's first nuclear weapons test, code-named Trinity, at Alamogordo, New Mexico. The first Soviet nuclear test is conducted August 29, 1949, at a test site near Semipalatinsk in Kazakhstan, and the first British nuclear test takes place October 3, 1952, near the Monte Bello Islands off Australia.

1954 -- April 2
INDIAN "STANDSTILL AGREEMENT"

Jawaharlal Nehru, prime minister of India, calls for a "standstill agreement" on nuclear testing, the first initiative of its kind.

1957 -- August 21
U.S. NUCLEAR TESTING PROPOSAL

U.S. President Dwight D. Eisenhower announces that the United States would be willing, as part of a first-step disarmament agreement, to suspend testing of nuclear weapons for up to two years under certain conditions and safeguards. These include Soviet acceptance of the U.S. call for a permanent cessation of the production of fissionable materials for weapons purposes and the installation of inspection systems to ensure compliance.

1958 -- March 31
SOVIET TESTING MORATORIUM

The Soviet Union announces that it will unilaterally halt all nuclear tests provided Western nations also stop testing.

1958 -- April 8-August 21
CONFERENCE OF EXPERTS

President Eisenhower proposes a Conference of Experts to examine the issues involved in verifying a nuclear test ban. The conference convenes on July 1 in Geneva with scientists from the United States, Britain, the Soviet Union, France, Canada, Czechoslovakia, Romania, and Poland. On August 21, the conference releases a report indicating that a comprehensive nuclear test ban (CTB) can be verified through a network of 160 monitoring stations and that nuclear tests in space out to 50 kilometers can be verified, but that current technology cannot detect tests in deep space.

1958 -- August 22
SECOND U.S. NUCLEAR TESTING PROPOSAL

President Eisenhower announces that the United States is prepared "to negotiate an agreement with other nations which have tested nuclear weapons for the suspension of nuclear weapons tests and the establishment of an international control system." If this proposal is accepted in principle by the other nations that have tested nuclear weapons, "then in order to facilitate the detailed negotiations, the United States is prepared, unless testing is resumed by the Soviet Union, to withhold further testing on its part of atomic and hydrogen weapons for a period of one year from the beginning of the negotiations. "

1958 -- October 31
CTB NEGOTIATIONS

The United States, Britain, and the Soviet Union begin negotiations on a comprehensive nuclear test ban at the Geneva Conference on the Discontinuance of Nuclear Weapons Tests. The United States and Britain begin a one-year testing moratorium, which the Soviet Union joins a few days later.

1959 -- April 13
U.S. NUCLEAR TEST BAN PROPOSAL

In a letter to Soviet Premier Nikita Khrushchev, President Eisenhower offers an alternative approach to a nuclear test ban: If the Soviet Union insists on a veto over an on-site control system to monitor underground detonations, the two sides could implement a test ban in phases, starting with a prohibition of nuclear weapons tests in the atmosphere up to 50 kilometers. Meanwhile, the negotiations could continue to resolve the political and technical problems associated with control of underground and outer space tests.

Premier Khrushchev rejects the proposal and suggests instead a CTB with a predetermined number of on-site inspections.

1959 -- May 5
U.S. NUCLEAR TEST BAN

In another letter to Premier Khrushchev, President Eisenhower urges technical discussions on the possibility of banning nuclear tests to a greater atmospheric height than that mentioned in his April 13 letter. The president again urges the Soviet Union either to accept the control measures that would make possible a complete ban on nuclear weapons tests or to agree to the U.S. proposal for a partial ban.

The president states that the United States is prepared to explore Premier Khrushchev's proposal for a predetermined number of inspections in the territory of the United States, Britain, and the Soviet Union, but adds that the number should be related to scientific facts and detection capabilities.

1959 -- August 26
EXTENSION OF U.S. MORATORIUM

President Eisenhower extends the voluntary one-year suspension of nuclear weapons testing by the United States to December 31, 1959.

1959 -- August 28
SOVIET STATEMENT ON MORATORIUM

The Soviet Union states that it will not resume nuclear testing provided the Western powers continue to observe a moratorium.

1959 -- December 29
EXPIRATION OF U.S. MORATORIUM

President Eisenhower announces that when the U.S. nuclear testing moratorium expires at the end of 1959, we "consider ourselves free to resume nuclear testing," but that the United States will not resume testing without advance notice.

1960 -- February 13
FIRST FRENCH NUCLEAR TEST

France explodes its first nuclear device at a test site in the Sahara Desert.

1960 -- May 2
U-2 INCIDENT A U.S.

U-2 reconnaissance plane is shot down over Sverdlovsk in the Soviet Union. Premier Khrushchev cancels a scheduled four-power Paris summit, and no further progress is made in the CTB negotiations for the balance of the Eisenhower administration.

1961 -- March 21
CONTINUATION OF CTB NEGOTIATIONS

After a policy review by the administration of U.S. President John F. Kennedy, the CTB negotiations between the United States, Britain, and the Soviet Union reconvene in Geneva. While the sides are close on many points, the United States and Britain call for 20 on-site inspections per year, while the Soviet Union proposes only three.

1961 -- April 18
CTB DRAFT TREATY

The United States and Britain introduce a draft CTB treaty at the Geneva negotiations proposing a ban on all nuclear tests except for underground explosions measuring less than 4.75 on the Richter scale. The plan further calls for a three-year moratorium on such underground tests while research on verification techniques continues. The Soviet Union rejects the verification provisions and presents counterproposals that are unacceptable to the United States and Britain.

1961 -- September 1
RESUMPTION OF SOVIET NUCLEAR TESTING

Arguing that increased international tensions and the French nuclear test program have created a changed security environment, the Soviet Union resumes atmospheric nuclear testing.

1961 -- September 3
ATMOSPHERIC TEST BAN PROPOSAL

In response to Soviet resumption of nuclear tests in the atmosphere on September 1, President Kennedy and British Prime Minister Harold Macmillan urge the Soviet Union to agree to a ban on atmospheric tests. Premier Khrushchev rejects this proposal. The United States resumes underground nuclear testing less than two weeks later, on September 15.

1962 -- March 2
U.S. ATMOSPHERIC TESTS

President Kennedy announces that the United States will resume atmospheric testing unless the Soviet Union agrees to the U.S.-British atmospheric test ban proposal by late April. In the absence of agreement, the United States resumes atmospheric testing on April 25.

1962 -- August 27
DRAFT TEST BAN TREATIES

The United States and Britain introduce two new draft test ban treaties. The first calls for a comprehensive ban on tests enforced by nationally manned control posts under international supervision and obligatory on-site inspection. The second, offered as an alternative, calls for a limited ban ending testing in all environments except underground and monitored by national technical means of verification without the need to establish any international verification machinery.

1963 -- June 10
TEST BAN TALKS

The United States, Britain, and the Soviet Union announce that high-level talks will be held in Moscow in July to seek agreement on a test ban. In a speech on the settlement of Cold War problems, President Kennedy says the United States will voluntarily suspend nuclear tests in the atmosphere pending negotiation of a test ban agreement, provided other countries follow suit.

1963 -- July 15-August 5
LIMITED TEST BAN TREATY

The United States, Britain, and the Soviet Union negotiate and sign on August 5 the Limited Test Ban Treaty (LTBT) outlawing nuclear tests in the atmosphere, in outer space, and underwater. Underground tests are also outlawed if they result in spreading radioactive debris outside the territorial limits of the state where the explosion is conducted. The treaty enters into force on October 10, 1963.

1964 -- October 16
FIRST CHINESE NUCLEAR TEST

China explodes its first nuclear weapon at Lop Nor on the Qinghai Plateau.

1968 -- July 1
NUCLEAR NON-PROLIFERATION TREATY

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) is signed by the United States, the Soviet Union, Britain, and 58 other countries. The preamble of the agreement refers explicitly to the CTB and to the "determination expressed by the Parties [to the treaty] to seek to achieve the discontinuance of all test explosions of nuclear weapons for all time." The NPT enters into force March 5, 1970.

1974 -- March/April
RESUMPTION OF DISCUSSIONS ON NUCLEAR TESTING LIMITS

The United States and the Soviet Union resume discussions on nuclear testing limits that lead to the Threshold Test Ban Treaty (TTBT) and the Peaceful Nuclear Explosions Treaty (PNET).

1974 -- May 18
INDIAN NUCLEAR TEST

India conducts its only nuclear test to date at an underground test site in the Rajasthan Desert.

1974 -- July 3
THRESHOLD TEST BAN TREATY

The United States and the Soviet Union sign the Treaty on the Limitation of Underground Nuclear Weapon Tests (the Threshold Test Ban Treaty). The treaty bans underground nuclear weapons tests with a yield exceeding 150 kilotons and obligates the parties to continue negotiations toward a CTB. The treaty provides for verification by national technical means, exchange of data on test site geology, and testing only on national territory at announced sites.

1976 -- May 28
PEACEFUL NUCLEAR EXPLOSIONS TREATY

U.S. President Gerald Ford and Soviet General Secretary Leonid Brezhnev sign the Treaty on Underground Nuclear Explosions for Peaceful Purposes (the Peaceful Nuclear Explosions Treaty), which sets a ceiling of 150 kilotons on such explosions, equal to that established in the TTBT. The treaty provides for verification by national technical means, information exchange, and access to the test site. Pending ratification, both parties pledge not to test above 150 kilotons.

1977 -- October 3
TRILATERAL CTB TALKS

Trilateral talks for a CTB begin in Geneva between the United States, Britain, and the Soviet Union. Over the next three years, progress is made on the draft treaty: The parties agree that the treaty will ban all nuclear weapons tests, suspend PNEs until they can be distinguished from weapons tests, establish an extensive verification regime (including national technical means and seismic monitoring stations), and permit on-site inspections to ensure confidence in the treaty. Differences remain on details of the verification regime, the definition of a "nuclear explosion," and the status of the treaty after its three-year term.

By 1979, the trilateral CTB negotiations are overshadowed by the Strategic Arms Limitation Treaty (SALT II) and, later, by the Soviet invasion of Afghanistan. The trilateral talks recess at the end of the administration of U.S. President Jimmy Carter (1981) and do not resume.

1980 -- October 16
LAST ATMOSPHERIC TEST

China conducts the last atmospheric nuclear test to date.

1982 -- July 19
TTBT AND PNET VERIFICATION PROTOCOLS

U.S. President Ronald Reagan determines that the United States will seek to negotiate additional verification protocols to the TTBT and PNET.

1985 -- July 29
MEASURING NUCLEAR TESTS

President Reagan invites Soviet experts to the U.S. test site in Nevada to measure the yield of a U.S. nuclear test with any instrumentation devices they think necessary.

1985 -- July 30
SOVIET TEST MORATORIUM

Soviet General Secretary Mikhail Gorbachev announces a nuclear testing moratorium to begin August 6 and last until the end of 1985. He pledges to continue the testing ban beyond December if the United States reciprocates.

1985 -- December 5
COMPREHENSIVE TEST BAN

In a letter to President Reagan, General Secretary Gorbachev proposes the resumption of negotiations on a CTB. On December 19, the White House states that: "A comprehensive test ban...is a long-term objective of the United States in the context of achieving broad, deep, and verifiable arms reductions, substantially improved verification capabilities, expanded confidence-building measures, greater balance in conventional forces, and at a time when a nuclear deterrent is no longer as essential an element as currently for international security and stability."

1986 -- January 15
SOVIET MORATORIUM EXTENSION

In connection with his three-stage nuclear disarmament plan, General Secretary Gorbachev extends the Soviet testing moratorium for three months beyond its December 31, 1985, expiration date.

1986 -- March 14
ON-SITE MONITORING OF NUCLEAR TESTS WITH CORRTEX

President Reagan announces a new, specific proposal for on-site monitoring of nuclear tests to strengthen the verification provisions of the TTBT and PNET. The proposal involves a hydrodynamic yield measurement method -- known as CORRTEX -- that Soviet scientists are invited to inspect at the U.S. test site and to monitor during a nuclear weapons test.

1986 -- May 14
SOVIET MORATORIUM EXTENDED AFTER CHERNOBYL

After the Chernobyl nuclear reactor accident, General Secretary Gorbachev extends the Soviet nuclear testing moratorium through August 6, 1986. It is later extended until the end of the year.

1986 -- July 25
GENEVA TALKS ON NUCLEAR TESTING

As a result of President Reagan's March 14 offer, U.S. and Soviet experts begin the first round of the Nuclear Testing Talks (NTT) in Geneva, Switzerland.

1987 -- January 13
VERIFYING NUCLEAR TESTING TREATIES

President Reagan sends a message to the U.S. Senate requesting advice and consent on ratification of the TTBT and PNET, with a reservation that will ensure the treaties do not take effect until they are effectively verifiable.

1987 -- February 5
END OF SOVIET MORATORIUM

The Soviet Union announces that, since the United States has not stopped testing, its own moratorium has ended. The Soviets resume nuclear tests on February 26.

1987 -- September 17
WASHINGTON MINISTERIAL

U.S. Secretary of State George Shultz and Soviet Foreign Minister Eduard Shevardnadze announce that "[t]he United States and Soviet sides have agreed to begin before December 1, 1987, full-scale stage-by-stage negotiations which will be conducted in a single forum. In these negotiations, the sides, as the first step, will agree upon effective verification measures which will make it possible to ratify the [TTBT and PNET], and proceed to negotiating further intermediate limitations on nuclear testing leading to the ultimate objective of the complete cessation of nuclear testing as part of an effective disarmament process."

1987 -- November 9
U.S.-SOVIET NTT TALKS

Based on the Washington ministerial, the Nuclear Testing Talks resume, with the focus on TTBT/PNET verification issues (see July 25, 1986).

1987 -- December 9
JOINT VERIFICATION EXPERIMENT

During a Washington summit, the United States and the Soviet Union agree to design and conduct a joint verification experiment (JVE) at each other's test sites. The U.S. portion of the JVE is conducted on August 17, 1988, and the Soviet portion on September 14, 1988. U.S. and Soviet scientists, technicians, and observers are present at both experiments.

1990 -- January 9
U.S. POLICY STATEMENT ON A CTB

U.S. President George Bush approves a policy statement on nuclear testing indicating that the United States "has not identified any further limitations on nuclear testing...that would be in the U.S. national security interest." The United States considers a CTB to be a "long-term objective" that will be attainable only "when we do not need to depend on nuclear deterrence."

1990 -- June 1
TTBT AND PNET VERIFICATION PROTOCOLS

Presidents Bush and Gorbachev sign the verification protocols to the unratified TTBT and PNET treaties.

1990 -- September 25/October 9
TTBT AND PNET RATIFICATION

The U.S. Senate ratifies the TTBT and PNET on September 25, the Supreme Soviet on October 9. The treaties enter into force on December 11, when the two sides exchange instruments of ratification at a ministerial meeting in Houston, Texas.

1990 -- October 24
LAST SOVIET NUCLEAR TEST

The Soviet Union conducts its last nuclear test before entering into a unilateral moratorium. Russia has continued to observe this testing halt.

1991 -- July 15
FRENCH TESTING MORATORIUM

France conducts its last nuclear test before entering into a unilateral nuclear testing moratorium that lasts until September 1995.

1991 -- October 5
SOVIET TESTING MORATORIUM

The Soviet Union announces a one-year, unilateral moratorium on testing and calls for an end to all nuclear tests.

1991 -- November 26
LAST BRITISH NUCLEAR TEST

Britain, which uses the U.S. test site in Nevada, conducts its last nuclear test before the U.S. moratorium takes effect.

1992 -- September 23
LAST U.S. NUCLEAR TEST

The United States conducts its last nuclear test to date.

1992 -- October 2
U.S. MORATORIUM

President Bush signs into law the Hatfield Amendment establishing a nuclear testing moratorium. The moratorium is subsequently extended by U.S. President Bill Clinton, first through September 1994 and then through September 30, 1996.

1992 -- October 19
RUSSIAN MORATORIUM

Russian President Boris Yeltsin extends the Russian moratorium on testing until July 1, 1993.

1993 -- January 13
FRENCH MORATORIUM

France announces it will not test nuclear weapons provided the United States and Russia do not test.

1993 -- February 2
CLOSURE OF SOVIET TEST SITE

Kazakhstan announces the closure of the Semipalatinsk nuclear test site.

1993 -- July 3
EXTENSION OF U.S. TESTING MORATORIUM

President Clinton extends the U.S. moratorium on nuclear testing "at least through September of [1994], as long as no other nation tests."

1993 -- August 10
CTB MANDATE

The United Nations Conference on Disarmament (CD) in Geneva agrees to give its Ad Hoc Committee on a Nuclear Test Ban a mandate to negotiate a comprehensive nuclear test ban treaty.

1994 -- January 14
MOSCOW SUMMIT STATEMENT

In a joint statement issued at a summit meeting in Moscow, Presidents Clinton and Yeltsin reaffirm their support for a CTB. The two leaders call for completing the treaty "as soon as possible" and for "other states to refrain from carrying out nuclear explosions while [CTB negotiations] are being held."

1994 -- January 25
CTBT NEGOTIATIONS

Negotiations on a CTB Treaty (CTBT) begin at the UN Conference on Disarmament in Geneva.

1994 -- March 14/January 30, 1995
EXTENSIONS OF U.S. MORATORIUM

On March 14, President Clinton extends the U.S. unilateral moratorium until the end of September 1996. On January 30, the United States announces that, assuming a CTBT is signed before September 30, 1996, the United States will not test before the CTBT enters into force.

1995 -- May 31
SOVIET NUCLEAR DEVICE AT SEMIPALATINSK

A Soviet nuclear device, which had been emplaced at the Semipalatinsk test site prior to the commencement of the moratorium and which was not retrievable, is destroyed by a chemical explosion. On October 3, the United States agrees to assist Kazakhstan in permanently shutting down the test site.

1995 -- June 13
RESUMPTION OF FRENCH NUCLEAR TESTING

French President Jacques Chirac announces that France will resume nuclear testing in September with a series of eight tests in the South Pacific to last until May 1996. Two months later, in the face of negative reaction, France announces that the tests will end more quickly.

1995 -- August 4
U.S. STOCKPILE STEWARDSHIP REPORT

The U.S. Department of Energy releases a major study on the U.S. nuclear weapons stockpile prepared by an independent group of senior nongovernmental scientists (the JASON group). The report finds that "the United States can, today, have high confidence in the safety, reliability, and performance margins of the nuclear weapons that are designated to remain in the enduring stockpile."

1995 -- August 11
U.S. "ZERO-YIELD" CTBT PROPOSAL

President Clinton announces that the United States plans to seek a true "zero- yield" CTBT banning all nuclear weapons test explosions. According to U.S. officials, "so long as we implement a strong science-based stockpile stewardship program, we can maintain a safe and reliable stockpile without tests of any size -- and can rule out even so-called hydronuclear experiments of a few pounds nuclear energy release."

1995 -- September 5
FRENCH NUCLEAR TESTS

France resumes nuclear testing in the South Pacific amid widespread international protests.

1995 -- October 5
RUSSIAN ACCEPTANCE OF ZERO-YIELD CTBT

At a summit meeting in Hyde Park, New York, with President Clinton, President Yeltsin agrees to a zero-yield CTBT.

1996 -- January 27
END OF FRENCH TESTS

France conducts its sixth and final nuclear test. Five days later, in an address to a joint session of the U.S. Congress, President Chirac announces that France has finished testing "once and for all" and states that France is prepared to push for completion of a zero-yield CTBT in 1996.

1996 -- June 8
CHINESE NUCLEAR TEST

In connection with its 44th nuclear weapons test, China announces its plan to conduct one more nuclear test before September 1996, after which it "will exercise a moratorium on nuclear testing" and will "work with other countries for the conclusion, within this year, of a fair, reasonable, and verifiable CTB treaty with universal adherence and unlimited duration."

1996 -- June 20
INDIAN REJECTION OF CTB TREATY

India announces that it will not sign the CTBT as drafted because the treaty would still permit the nuclear weapon states to "continue refining and developing their nuclear arsenal" (see April 2, 1954).

1996 -- June28
DRAFT CTB TREATY

The chairman of the Nuclear Test Ban Ad Hoc Committee submits a compromise draft CTB treaty for approval by the UN Conference on Disarmament. In a statement issued by the White House, President Clinton applauds this action as bringing "us one step closer to the day when no nuclear weapons are detonated anywhere on the earth." Because of the objections of India, however, the CD is unable to agree to forward the draft to the UN.

1996 -- July 29
LAST CHINESE NUCLEAR TEST

China conducts its 45th known nuclear test and announces a unilateral moratorium on testing pending the conclusion of a CTBT.

1996 -- August 9
CTBT NEGOTIATIONS

After consultations in the Nuclear Test Ban Ad Hoc Committee, its chairman announces that he has confirmed that continuing negotiations on the draft treaty as a whole would not yield further results. On August 16, the committee meets and agrees to report to the CD that "no consensus" could be reached either on adopting the text of the CTBT or on formally passing it to the CD, owing to objections by India.

1996 -- August 23
AUSTRALIAN RESOLUTION

Australian Foreign Minister Alexander Downer announces that Australia will sponsor a resolution seeking endorsement of the CTBT from the United Nations General Assembly and its opening for signature at the earliest possible date.

1996 -- September 10
UNGA ADOPTION OF CTBT

The United Nations General Assembly reconvenes and votes 158 to 3 to adopt the Comprehensive Test Ban Treaty and open it for signature at the earliest possible date. India, Bhutan, and Libya vote against, while Cuba, Lebanon, Syria, Mauritius, and Tanzania abstain.

1996 -- September 24
SIGNING OF CTBT

President Clinton is the first world leader to sign the CTBT. Over the next two days, an initial group of 70 other nations including Britain, China, France, and Russia sign the CTBT. As of early November 1997, 148 signatures and eight ratifications had been obtained.