12 © The Containment of Underground Nuclear Explosions The test was followed 2 weeks later by the 500 kiloton explosion ‘‘King,’’ the largestfission weapon evertested. At the Nevada Test Site, low-yield fission devices continued to be tested. Tests were conducted with nuclear bombs dropped from planes, shot from cannons, placed on top of towers, and suspended from balloons. The tests were designed both to develop new weapons and to learn the effects of nuclear explosions on civilian and military structures. Some tests were conducted in conjunction with military exercises to prepare soldiers for what was then termed ‘‘the atomic battlefield.’’ In the Pacific, the next tests of thermonuclear (hydrogen) bombs were conducted under ‘‘Operation Castle," a series of six tests detonated on the Bikini Atoll in 1954. Thefirst test, ‘*Bravo,’’ was expected to have a yield of about 6,000 kilotons. The actual yield, however, was 15,000 kilotons-—over twice what was expected.® The radioactive fallout covered an area larger than anticipated and because of a faulty weather prediction,the fallout pattern was more easterly than expected. A Japanese fishing boat, which had accidentally wandered into the restricted zone without being detected by the Task Force, was showered with fallout. When the fishing boat docked in Japan, 23 crew members had radiation sickness. The radio operator died of infectious hepatitis, probably because of the large number of required blood transfusions.’ The faulty fallout prediction also led to the overexposureof the inhabitants of two of the Marshall Islands 100 miles to the East. In a simi!ar though less severe accident, radioactive rain from a Soviet thermonuclear testfell on Japan.’ These accidents began to focus world- wide attention on the increased level of nuclear testing and the dangers of radioactive fallout. Public Opposition to atmospheric testing would continue to mount as knowledge of the effects of radiation increased and it became apparent that no region of the world was untouched.’ Attempts to negotiate a ban on nuclear testing began at the United Nations Disarmament Confer- ence in May 1955. For the next several years efforts to obtain a test ban were blocked as agreements in nuclear testing were linked to progress in other arms control agreements and as differences over verification requirements remained unresolved. In 1958, President Eisenhower and Soviet Premier Khrushchev declared, through unilateral public statements, a moratorium on nuclear testing and began negotiations on acomprehensivetest ban. The United States adopted the moratorium after conducting 13 tests in seven daysat the end of October 1958. Negotiations broke down first over the right to perform onsite inspections, and then over the number of such inspections. In December 1959, President Eisenhower announced that the United States would no longer consider itself bound by the ‘‘voluntary moratorium’’ but would give advance notice if it decided to resume testing. Meanwhile (during the moratorium), the French began testing their newly acquired nuclear capability. The Soviet Union, which had announced that it would observe the moratorium as long as the western powers would not test, resumed testing in September 1961 with a series of the largest tests ever conducted. The United States resumedtesting two weeks later (figure 2-1),!° Public opposition to nuclear testing continued to mount. Recognizing that the U.S. could continueits development program solely through underground testing and that theratification of a comprehensive test ban could not be achieved, President Kennedy proposed a limited ban on tests in the atmosphere, the oceans, and space. The Soviets, who through their own experience were convinced thattheir test program could continue underground, accepted the proposal. With both sides agreeing that such a treaty could be readily verified, the Limited Test Ban Treaty (LTBT) was signed in 1963, banning all aboveground or underwatertesting. Jn addition to military applications, the engineering potential of nuclear weapons was recognized by the mid-1950’s. The Plowshare Program was formed in 1957 to explore the possibility of using nuclear explosions for peaceful purposes.'!! Among the SBravo was the largest test ever detonated by the United States. See ‘The Voyage of the Lucky Dragon,”’ Ralph E. Lapp, 1957, Harper & Brothers Publishers, New York. Arms Control and Disarmament Agreements,’ United States Arms Control and Disarmament Agency, Washington, DC, 1982 Editon, p. 34 Since the large thermonuclear tests. all people have strontium-90 (a sister element of calcium) in their bones, and cestum-137 (a sister element of potassium) in their muscle. Also, the amountof iodine-131 in milk in the United States correlates with the frequency of atmospheric testing. 10See ** Arms Control and Disarmament Agreements,'’ United States Arms Control and Disarmament Agency, 1982 edition. The name is from ‘*.... they shal! beat theur swords into plowshares,”’ Isaiah 2:4.