Chapter 2—The Nuclear Testing Program e 13 Figure 2-1—U.S. Nuciear Testing TTBT LTBT 4 I ! I t I I 100 90 ' Number of tests 80 ! ' I 70P | I | 60 40P I \ ! J | 30 | SOF | I I | I 20r 0 1945 Key: LTBT = 1963 Limited Test Ban Treaty TTBT = 1974 Threshoid Test Ban Treaty 1 1950 1955 1960 [} Above-ground tests 1965 1970 1975 1980 1985 Years a Underground tests SOURCE: Data from the Swedish Defense ResearchInstitute. applications considered were the excavation of canals and harbors, the creation of underground storage cavities for fuel and waste, the fracturing of rock to promote oil and gas flow, and the use of Estimates of the engineering requirements indicated that approximately 250 separate nuclear explosions with a total yield of 120 megatons would be required to excavate the canal through Panama. Furthermore, fires. It was reported that even more exotic applications, such as melting glaciers for irrigation, were being considered by the Soviet Union. kilometers of territory would need to be evacuated for the duration of the operation and several months thereafter.'3 Because it was also clear that no level of radioactivity would be publicly acceptable, the program was terminated in the early 1970s. nuclear explosionsto cap oil gushers and extinguish The first test under the Plowshare Program, ‘‘Gnome,”” was conducted 4 years later to create an underground cavity in a large salt deposit. The next Plowshare experiment, Sedan in 1962, used a 104 kiloton explosion to excavate 12 million tons of earth. In 1965, the concept of ‘‘nuclear excavation’’ was refined and proposed as a meansof building a second canal through Panama.'? Three nuclear excavations were tested under the Plowshare pro- gram (‘‘Cabriolet,’’ Jan. 26, 1968; *‘Buggy,’” Mar. 12, 1968; and ‘*‘Schooner,’’ Dec. 12, 1968). Schoo- ner, however, released radioactivity off site and, as a consequence, no future crater test was approved. Consideration of the radiological and logistical aspects of the project also contributed to its demise. fallout predictions indicated that 16,000 square In 1974, President Richard Nixon signed the Threshold Test Ban Treaty (TTBT) restricting all nuclear test explosions to a defined test site and to yields no greater than 150 kilotons. As a result, all U.S. underground nuclear tests since 1974 have been conducted at the Nevada Test Site. As part of the earlier 1963 Limited Test Ban Treaty. the United States established a series of safeguards. One of them, ‘‘Safeguard C,”’ requires the United States to maintain the capability to resume atmospheric testing in case the treaty is abrogated. The Department of Energy (DOE) and the Defense Nuclear Agencycontinue today to maintain a facility for the '2The 1956 war over the Suez Canal created the first specific proposals for using nuclear explosions to create an alternative canal. '3Bruce A. Bolt, ‘‘Nuclear Explosions and Earthquakes, The Parted Veil’’ San Francisco, CA: W.H. Freeman & Co., 1976, pp. 192-196.