Silencing the Bomb Read online

  Discussion of a full test ban did not extend beyond the first day of the negotiations. The three principals very quickly agreed to a limited test ban treaty (LTBT), which was signed on August 5, 1963. It prohibited any explosion that “causes radioactive debris to be present outside the territorial limits of the State under whose jurisdiction or control such explosion is conducted.” The treaty was opened to signature by all states three days later and entered into force on October 10, 1963.

  The treaty was of indefinite duration but with an escape clause for a national security emergency. Each country could conduct monitoring using its own means, so-called national technical means (NTM), including satellite surveillance. The treaty included neither on-site inspections nor seismic stations on the territories of the others.

  SUPPORT FOR AND OPPOSITION TO THE LIMITED TEST BAN TREATY

  As urgent as it was to pass agreements curbing the nuclear arms race, serious dissent was expressed in both the Eisenhower and Kennedy administrations about not only a Comprehensive Nuclear Test Ban Treaty (CTBT) but also a Limited Test Ban Treaty (LTBT). In June 1963, President Kennedy held a vigorous debate at a meeting of his Committee of Principals for Nuclear Testing about the positions the United States should take in upcoming test ban negotiations with the Soviet Union and Britain. That debate occurred in the wake of the Cuban Missile Crisis of late 1962.

  Much of the material and several quotes that follow are from Glen Seaborg’s 1981 book. (I felt honored in the 1980s when he congratulated me at a meeting of the U.S. National Academy of Sciences for my work on nuclear verification.) According to Seaborg, Secretary of Defense Robert McNamara “supported the draft treaty because he felt that the United States was ahead and that a test ban would freeze our superiority.” Jerome Wiesner, Kennedy’s science adviser, said “the [weapons] laboratory directors were not in a position to judge policy considerations.” Secretary of State Dean Rusk said he thought the draft treaty, which included underground testing, “was consistent with all of the interests of the country, including national security.” Rusk went on to state “it was his impression that the Principals had all agreed that the risks to national security from an unlimited arms race were greater than the risks from a test ban treaty.” According to Seaborg, “Rusk doubted that any amount of discussion would ever bring the technical people to agree among themselves.”

  On behalf of the Joint Chiefs of Staff, General Maxwell Taylor stated that under the western draft treaties of August 1962, the Soviet Union could make important gains in weapons development through clandestine testing. Taylor also said the Joint Chiefs would likely prefer a limited ban with a continuation of underground testing. According to Seaborg, the Joint Chiefs relied heavily on the directors of the weapons laboratories for their information. A number of dissenters were from those labs. Seaborg said that McNamara referred to statements made by R. W. Henderson of the Sandia Laboratory and John Foster, director of the Livermore weapons lab, to the effect that U.S. warheads could not penetrate to Soviet targets unless further tests were undertaken to correct defects. Foster continues to oppose a full test ban today.

  Seaborg reported that at the end of June 1963 Kennedy was pessimistic about a comprehensive test ban treaty (CTBT), based mainly on the impasse about the attributes and number of on-site inspections. One senator reported to Kennedy in 1963 that a CTBT likely would be ten votes shy of the mandatory sixty-seven (two-thirds) needed for U.S. Senate approval of the treaty. According to Seaborg, the exclusion of underground tests from the Moscow talks in 1963 was all but sealed when Khrushchev accused the West on July 2 of demanding on-site inspections for espionage purposes.

  Seaborg regarded “the failure to achieve a comprehensive test ban as a world tragedy of the first magnitude.” He went on to state, “While I did not take this position at the time [1963], looking back I tend to agree with those who feel that our concern about Soviet cheating was exaggerated…it is doubtful that clandestine tests the USSR might have undertaken in violation of a comprehensive treaty would have been militarily significant in the aggregate.”

  Seaborg stated that Kennedy threw himself into the ratification process. In contrast, President Clinton’s involvement was largely lacking when the Senate defeated the Comprehensive Test Ban Treaty in 1999 after allowing little time for testimony or debate. In anticipation of the Senate debate and vote in 1963, Kennedy was adroit in having a bipartisan group of senators attend the signing ceremony for the Limited Test Ban Treaty (LTBT) in Moscow. Kennedy did not want to see the treaty defeated by Republicans and southern Democrats nor have it go down to defeat like the Versailles Treaty under President Woodrow Wilson.

  During the Senate debates on the limited test ban in 1963, Secretaries Rusk and McNamara testified in favor of it. Seaborg pledged that the Atomic Energy Commission “would continue under the treaty to support vigorous research and development programs in its weapons laboratories and would thus be able to retain able scientists and engineers, attract new ones, and maintain the vitality of the laboratories.” General Taylor recommended four safeguards that the Joint Chiefs of Staff thought were necessary: (1) a continuing program of underground testing, (2) maintenance of modern nuclear laboratories, (3) the ability to resume atmospheric testing if required, and (4) improved monitoring capabilities. He concluded that if those safeguards were established, the risks inherent in the treaty could be accepted through a stabilization of international relations.

  Edward Teller, often called the father of the H-bomb, gave several reasons why he opposed the LTBT: (1) the treaty involved a field that had repeatedly proved itself unpredictable; (2) it would prevent the United States from acquiring information about weapons effects needed to design defenses against incoming ballistic missiles; (3) it would stimulate, not subdue, the arms race; (4) it would not deter proliferation; and (5) it would seriously wound the U.S. Plowshare program for peaceful uses of nuclear explosions. He argued that the Soviets had acquired knowledge of weapons they would need for defense against incoming ballistic missiles during their nuclear tests of 1962.

  Several prominent scientists and administrators disagreed with Teller on weapons for defense against incoming ballistic missiles. For example, Norris Bradbury, the director of Los Alamos, characterized the treaty as “the first sign of hope that international nuclear understanding is possible.” But John Foster, director of Livermore, had serious reservations about the LTBT and reiterated a number of the points made by Teller. Lewis Strauss, former chairman of the Atomic Energy Commission under Eisenhower, saw no advantage to the treaty.

  General Thomas Power, commander of the Strategic Air Command, also expressed strong opposition to the Limited Test Ban Treaty. He said the security of the United States depended on having overwhelming superiority over the Soviet Union and that atmospheric testing was needed to achieve that superiority. He and some others seemed to yearn for a prior era in which superiority and massive retaliation were possible U.S. policies. Soviet diplomats stated that they would not allow the United States to have the superiority it possessed in 1962 during the Cuban Missile Crisis. Although the USSR had not reached parity with the United States in nuclear weapons and their delivery systems in 1963, the passage of the LTBT could not prevent the Soviet Union from inflicting unprecedented and immense amounts of damage and loss of life on the United States in a major exchange of nuclear arms.

  Prior to the full floor debate by the Senate, President Kennedy wrote to both the majority and minority members of the Senate pledging to implement the four safeguards recommended by the Joint Chiefs of Staff. Two key senators, Everett Dirksen and Henry Jackson, who were expected to vote against the treaty, came out in favor of it. On September 24, 1963, the Senate approved the Limited Test Ban Treaty by a vote of 80 to 19.

  POSITIVE AND NEGATIVE CONSEQUENCES OF LTBT

  The Limited Test Ban Treaty of 1963 had both positive and negative effects. It led to a great reduction in radioactive fallout and pollution from atmospheric tests. In that
sense, it was a successful public health measure and an environmental accomplishment. Because nuclear fallout was eliminated, interest in a full test ban nearly ceased. Nevertheless, many people hoped the LTBT would act as a brake on the arms race and would lead to further arms control agreements, including a full test ban, and to nuclear disarmament.

  The LTBT did not put an end to the detonation underground of progressively larger numbers and yields of nuclear weapons. The arms race continued with the development of new weapons, tested underground rather than in the atmosphere. By the late 1960s, the USSR and the United States had conducted underground tests of hundreds of kilotons. Without the LTBT, however, it is possible that each would have conducted even larger tests in the atmosphere.

  The LTBT was the first treaty with the Soviets that involved nuclear arms. The Cuban Missile Crisis led the superpowers to negotiate a treaty that they thought would be a step toward preventing nuclear war. Other treaties followed, albeit with long lag times, involving reductions in intercontinental and intermediate-range (300 to 3500 miles, or 500 to 5500 km) missiles, weapons to knock down ballistic missiles, and nuclear weapons in outer space.

  U.S. nuclear doctrine changed from “massive retaliation” in Eisenhower’s presidency to what was termed “flexible response” during the Kennedy administration. The LTBT came at a time of transition from great U.S. superiority in nuclear weapons and intercontinental delivery systems to approximate parity with the Soviet Union. Emphasis after 1963 focused on specific arms control agreements and not on general disarmament.

  Seaborg stated, “It was always the view of Kennedy and his advisors that a comprehensive test ban would be far more effective than a limited test ban in preventing the proliferation of nuclear weapons.” Neither France nor China, which developed and tested nuclear weapons for the first time in the early to mid-1960s, signed the LTBT. They continued testing in the atmosphere until 1974 and 1980, respectively. Both then tested solely underground until just before they signed the CTBT in 1996.

  A CTBT in 1963 probably would not have deterred France and China from continuing to develop and test nuclear weapons. India signed the LTBT and did not conduct a nuclear test until 1974, which it claimed was for peaceful purposes. India might have been persuaded not to acquire nuclear weapons if a full test ban had been enacted in 1963. Its greatest concern in 1974 was not so much Pakistan as the nuclear capabilities and military strength of China. If India had not tested, it is possible that Pakistan would not have developed and tested nuclear weapons. Neither India nor Pakistan, nor later North Korea, tested in the atmosphere, only underground. The LTBT may have encouraged the Treaty for the Prohibition of Nuclear Weapons in Latin America, which entered into force in 1968. Since then, treaties have established nuclear-free zones in several other regions.

  A Comprehensive Test Ban Treaty in 1963 would have halted the development of weapons for new long-range missiles, but this was not to be. At that time, the United States possessed only single-warhead missiles such as Minuteman I and Polaris. Likewise, in 1963 the Soviet Union only had intercontinental missiles with single warheads. The United States, followed by the Soviet Union, developed multiple independently targetable reentry vehicles (MIRVs) for long-range missiles. A MIRVed missile carries more than one reentry vehicle and its nuclear warhead. Each of those warheads can be sent independently to separate targets, hence the name MIRV.

  The sum of the nuclear yields on a MIRVed missile is about half the yield on a single-warhead missile of similar size. Each MIRVed missile, however, is more dangerous in that its several warheads can be detonated over a larger area, causing more destruction than a large warhead carried by one missile. A single large warhead on a non-MIRVed missile, though twice as large, expends much of its energy higher in the atmosphere, not near the surface of the Earth. With the development of MIRV and more accurate missiles, somewhat smaller yield weapons largely replaced megaton-size warheads. The yields of individual warheads on land-based and submarine-based MIRVed missiles of the United States and the USSR are in the range 50 to 750 kilotons.

  In the early 1970s, the Soviet Union tested new warheads for its MIRVed missiles. Clearly, a full test ban in 1963 or somewhat later would have prevented that testing and deployment. The same is true for the MIRVed warheads on the U.S. Minuteman III, Peacekeeper (MX), Poseidon C3, Trident I C4, and Trident II D5 missiles.

  MIRVed missiles were one of the most dangerous aspects of the nuclear arms race between the United States and the USSR, especially as missile accuracy improved. They have not been eliminated and are still very dangerous today. Several warheads on one MIRVed missile could be aimed independently at several missiles of the other superpower. Because MIRVed nuclear missiles could be used in a first strike, they put each of the two superpowers in the very dangerous posture of launching its missiles very quickly in response to a warning that may have been a false alarm.

  A full test ban in 1963 could have prevented the development and testing underground of nuclear weapons for missile defense, as in the very large U.S. Amchitka explosions Milrow in 1969 and Cannikin in 1971 and advanced Soviet anti-ballistic weapons. Weapons for cruise missiles and MIRVed intermediate-range missiles, such as the Soviet SS-20, would not have been developed and tested.

  The Cannikin warhead was designed several years before it was detonated in 1971. It was to be part of the Safeguard anti-ballistic missile (ABM) system, which was abandoned almost two years before the Cannikin test for reasons of cost and technical difficulties. Much public outcry arose understandably about stationing ABM systems with very large nuclear warheads near U.S. cities. The British newspaper the Guardian stated just before the Cannikin test, “When President Nixon canvassed the opinion of seven Government agencies, his own Office of Science and Technology pointed out that the test was of only marginal technical usefulness. Of the seven agencies canvassed only two, the U.S. Atomic Energy Commission and the Department of Defense, expressed approval.” The costs of carrying out the Milrow and Cannikin tests at remote Amchitka Island in the western Aleutians must have exceeded a billion dollars.

  4

  ATTEMPTS TO HIDE NUCLEAR TESTS: THE BIG-HOLE EVASION SCHEME

  One of the major issues related to monitoring a full nuclear test ban involves the possibility of evasive testing, particularly what is referred to as decoupling or muffling the seismic signals of an underground nuclear explosion. Sometimes also called the big-hole hypothesis, its vast overexaggeration was critical in excluding underground tests from the Limited Test Ban Treaty in 1963.

  Most nuclear explosions were conducted without any attempts to muffle or decouple their seismic waves. They were fully coupled or tamped events in which the surrounding rock was in close or nearby contact with the nuclear device. They produced extremely large permanent (nonelastic) rock deformation, including vaporization of rock near the shot point. In contrast, full decoupling involves keeping the rock surrounding a large cavity in the elastic domain so that no permanent deformation occurs.

  In 1959 Edward Teller, a controversial physicist who was then at the Lawrence Livermore National Laboratory and had worked on the U.S. nuclear weapons program during and after World War II, and Albert Latter of the Rand Corporation, a nonprofit institution that advises the executive branch of the U.S. government, argued that seismic signals from underground nuclear explosions could be greatly reduced—that is, greatly muffled—by detonating them in large underground cavities. They convinced many people in the United States during the late 1950s and 1960s that monitoring could not keep up with the ability to either evade detection or disguise the seismic signals from nuclear explosions.

  This turned out not to be the case; verification clearly kept ahead of evasion for decades. Misstatements about decoupling, whether driven by those who were poorly informed or others who purposefully misled, were made again in the 1999 Senate debate about ratification of the Comprehensive Nuclear Test Ban Treaty (CTBT). Three senators argued in that debate that decoupling could all
ow huge nuclear explosions to be hidden from U.S. and international monitoring. The decoupling concept was not new; it had been around since 1959, contrary to what those senators implied in 1999. As I explain later in this chapter, a gigantic cavity at a considerable depth in the Earth is needed to decouple or muffle even a small nuclear explosion, plus there is the need to insure that its radioactive products do not leak to the surface of the Earth where they could be detected. These are formidable obstacles for a potential evader.

  Latter’s 1959 estimates of the amount of muffling of seismic waves achieved by a decoupled underground explosion were based on data from the single very small U.S. underground explosion in 1957 called Rainier. It actually was not muffled; unlike the hard rock at the two main Soviet test sites, from which seismic waves propagate efficiently, Rainier was detonated in relatively soft rock in Nevada and produced small seismic signals.

  Far too many policy makers in the United States in the 1960s placed too much credence on the work as well as on the arguments and testimony of Latter and Teller. Both men were major proponents of the concept that successful decoupling was possible and strong advocates of continued nuclear testing. Latter and his associates concluded that seismic waves from Rainier would have been smaller by a factor of forty to fifty if it had been conducted in a large underground cavity at depth in the same rock. They predicted an amplitude reduction of three hundred times relative to Rainier for a fully decoupled underground explosion in salt deposits, which turned out to be quite incorrect.

  In joint congressional testimony in 1960, Representative Chester Holifield asked, “Let us understand what that means. Does that mean that a 300-kiloton shot could be reduced in seismic recordings to a 1 kiloton recording?” Latter answered, “Yes, sir.” Senator Gore went on to ask, “Do you agree with that, Dr. Romney?” Seismologist Carl Romney replied, “Yes, indeed.”