"And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war any more." - Isaiah 2:3-5
|Fig. 1: The Sedan crater. (Courtesy of National Nuclear Security Administration / Nevada Field Office.)|
Operation Plowshare was a program officially established by the Atomic Energy Commission (AEC) in 1958 to explore the technical and economic feasibility of using nuclear explosives for industrial applications. Until its termination in 1975 for environmental, technical, and political reasons, 27 nuclear tests were carried out. These experiments examined the possibility of using nuclear explosives for major excavation projects, underground fracturing for fossil fuel production and mineral leaching, creation of artificial aquifers, and chemical isotope manufacture. 
Scientists and government personnel began to express interest in developing nuclear explosives for productive peacetime activities in the 1950s. Strong international reactions to Egypt's nationalization of the Suez Canal in 1956 prompted consideration for a nuclear excavation of a second canal. Though this issue was resolved diplomatically, it brought the possibility of nuclear excavation for major civil engineering projects into the mainstream. 
On June 27, 1957, the AEC approved the establishment of the Plowshare Program by LRL's Division of Military Application. A Division of Peaceful Nuclear Explosives would soon be created to assume responsibilities associated with the project. On September 19, 1957, the first US underground nuclear test (codenamed Ranier) provided the first experimental data for possible engineering uses of nuclear explosives; this was a major impetus for the further development and expansion of Plowshare. The existence and mission of the Plowshare program was publicly announced by the AEC on June 6, 1958. 
During the nuclear testing moratorium that went into effect on October 31, 1958, numerous non-nuclear preparatory experiments (including high explosive tests) were conducted, with major plans and proposals for nuclear tests and civil engineering projects under development. Upon the Soviet Union's unilateral end to the moratorium on September 1, 1961, the United States was fully prepared to carry out its peaceful nuclear testing program. 
Gnome, the first post-moratorium test conducted under the Plowshare program on December 10, 1961, was an underground blast near Carlsbad, NM. Gnome's goal was "to determine if the underground nuclear detonation in a salt medium could produce steam that could run an electric generator and also to obtain information regarding the recovery of radioisotopes for medical and other purposes." 
|Fig. 2: Post-detonation cross-section of the Rulison test site.  (Courtesy of the U.S. Department of Energy)|
A major goal of Plowshare was to develop nuclear explosives for excavation. In 1962, a US Corps of Engineers Nuclear Cratering Group was formed at LRL for the purpose of advising Plowshare on civil engineering matters. 
The first and most dramatic cratering experiment was Sedan, conducted at the Nevada test site (NTS) on July 6, 1962. At 104 kt Sedan displaced 12 million tons of earth and created a crater 400 m across and 100 m deep. 
The Buggy test (March 1968) was notable for being the only row-charge detonation in the US nuclear testing program. 
Stimulation of low-permeability natural gas formations emerged as the most promising use for peaceful nuclear explosions. Experiments to this end were the only joint government-industry nuclear tests. Gasbuggy was the first of these tests, conducted on December 10, 1967, near Farmington, NM. This was a 29 kt blast 1,292 m underground, which created a "chimney" of fractured rock intended to allow trapped oil and gas to flow freely. Rulison was a similar test carried out in Grand Valley, CO. Rio Blanco was a simultaneous detonation of three 33-kt charges spaced from 1,780 m to 2,039 m in depth along the same vertical shaft. Private corporations involved in these tests included the El Paso Natural Gas Company (Gasbuggy), the Austral Oil Company (Rio Blanco), Conoco (Rio Blanco), and CER Geonuclear Corporation (Rio Blanco and Rulison). [2-4]
The Rulison test produced a less-than-expected 455 million cubic feet of natural gas, though tritium contamination rendered it unacceptable for public use. 
The potential for environmental contamination from such activities was considered to be low due to the impermeability of the surrounding rock. Ongoing monitoring programs have reported no environmental hazards outside of the immediate subterranean test area. [2-4]
|Fig. 3: The proposed Project Chariot harbor, showing the original plan and the later scaled-down version. (Source: Wikimedia Commons)|
Project Chariot was, in many respects, the flagship of the early Plowshare program, intended to be a full-scale exhibition of civil engineering using nuclear excavation. Chariot would have created an artificial harbor some 30 miles southeast of Point Hope, Alaska, 125 miles north of the Arctic Circle. Although the original concept called for the simultaneous detonation of about 2.4 megatons of nuclear ordnance, this was later scaled down to two 200-kt blasts to create the harbor, plus two to three 20-kt row charges to create a channel to the sea. [5,6]
Chariot came remarkably close to being carried out. An area almost the size of Delaware was set aside by the Department of the Interior, and 40 environmental studies were conducted at the site by the AEC between 1959 and 1962 in preparation for the shot. [5,6]
Chariot was met with strong public opposition, especially from the Eskimo residents of the Point Hope area. The economic and military value of the project was also dubious. These combined factors led to the effective cancellation of the project in 1962. [5,6]
Chariot was not the only artificial harbor project proposed under Plowshare. A 1971 report examined the possibility of blasting an artificial harbor into the coast of South America, with 33 proposed sites. 
The idea of a sea-level waterway (a canal requiring no locks) was also quite popular during the Plowshare era; such projects were the most ambitious ever proposed. In 1965, the Atlantic-Pacific Interoceanic Canal Study Commission (the Anderson Commission) was established to explore the possibility of constructing a sea-level waterway across central America. During subsequent years, several routes were proposed. The shortest were through Panama and northern Colombia, although one route covered nearly 140 miles through southern Mexico. These canals were to be hundreds of meters wide and tens of meters deep in order to accommodate large vessels like the newly-constructed USS Forrestal. [1,8,9]
At least one other study proposed the use of nuclear explosives to excavate a 160-mile sea-level canal between the Mediterranean Sea and the Gulf of Aqaba (a route that passed through Israel at the time), as well as a channel to the Dead Sea for hydroelectric generation. 
In 1970, the Anderson Commission recommended to the Nixon administration that the US not make any policy decisions on the assumption that suitable nuclear excavation technology would be available for any such project. 
Another Plowshare project was Carryall, a proposed roadcut for rerouting both Interstate 40 and the Atchison, Topeka, and Santa Fe Railway through the Bristol Mountains in southern California. This would have involved 22 nuclear explosives with yields from 20 to 200 kt to create an artificial valley two miles long and 100 m deep, moving about 68 million cubic yards of earth. The detonations were scheduled for early 1966; however, by this time the California Division of Highways had decided to begin excavation by conventional methods about one mile north of the original proposed route. 
This is but a snapshot of the highest-profile nuclear excavation plans that were given serious consideration under Plowshare. However, there were a multitude of proposals for a wide range of projects. The three-volume, six-year environmental field study completed in 2011 by Beck, Edwards, and King contains a short summary of each of these. 
Ultimately, environmental and technical concerns won out over the technological appeal of using nuclear explosives for peaceful purposes. Funding for the Plowshare program was finally halted in 1975. 
© Devon Powell. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 C.M. Beck, S.R. Edwards, and M.L. King. "The Off-Site Plowshare and Vela Uniform Programs: Assessing Potential Environmental Liabilities Through an Examination Of Proposed Nuclear Projects, High Explosive Experiments, and High Explosive Construction Activities," U.S. Deparment of Energy, DOE/NV/26383-22, Vol. I, Vol. II, Vol. III, September 2011.
 "Rio Blanco, Colorado Site Fact Sheet," U.S. Department of Energy, 5 Oct 11.
 "Gasbuggy, New Mexico Site Fact Sheet," U.S. Department of Energy, 25 Apr 11.
 "Rulison, Colorado Site Fact Sheet," U.S. Department of Energy, 5 Oct 11.
 D. O'Neill, "Project Chariot: How Alaska Escaped Nuclear Excavation," Bull. Atomic Scientists 45, No. 10, 28 (1989).
 "Chariot, Alaska Site Fact Sheet," U.S. Department of Energy, 20 Aug 13.
 H. H. Zodtner, "An Investigation of the Feasibility of Building a Harbor on the West Coast of South America Using Explosive Power of Nuclear Weapons, a Preliminary Report," UCRL-ID-125513, 31 Dec 71.
 R. A. Miles, "Isthmus of Tehuantepec," UCRL-ID-126133, 25 Mar 58.
 C.P. Lindner, "Channel Stabilization: Interoceanic Sea-Level Canal, Lower Atrato River Portion, Route 25, Colombia, South America," US Army Corps of Engineers, October 1969.
 H.D. MacCabee, "Use of Nuclear Explosives for Excavation of a Sea-Level Canal Across the Negev Desert in Israel, Connecting the Mediterranean with the Gulf of Aqaba," UCRL-ID-124767, 1 Jul 63.