Operation Plowshare, not to be confused with the anti-nuclear Plowshares Movement, was the overall United States term for the development of techniques to use nuclear explosives for peaceful construction purposes. The phrase was coined in 1961, taken from Isaiah 2:4 ("And he shall judge among the nations, and shall rebuke many people: and they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war any more"). It was the U.S. portion of what are called Peaceful Nuclear Explosions (PNE). The Soviet Union had a similar program of testing as well for many years [1].

Suggested usage

Proposed uses included widening the Panama Canal, constructing a new sea-level waterway through Nicaragua, cutting paths through mountainous areas for highways, and for connecting inland river systems. Other proposals involved blasting underground caverns for water, natural gas, and petroleum storage. Serious consideration was also given to using these explosives for various mining operations. One proposal suggested using nuclear blasts to connect underground aquifers in Arizona. Another plan involved surface blasting on the western slope of California's Sacramento Valley for a water transport project. At the end of the program, a major objective was to develop nuclear explosives, and blast techniqes, for stimulating the flow of natural gas in "tight" underground reservoir formations.

The use of nuclear explosives for commercial engineering purposes has not been utilized in the United States, but the concept has been tested.

Plowshare testing

One of the first plowshare nuclear blast cratering proposals that came close to being carried out was Project Chariot, which would have used several hydrogen bombs to create an artificial harbor at Cape Thompson, Alaska . It was never carried out due to concerns for the native populations and the fact that there was little potential use for the harbor to justify its risk and expense. After the project was terminated, a proof-of-concept 104 kiloton (435 terajoule) cratering blast was conducted on July 6, 1962 at the north end of Yucca Flats, within the Atomic Energy Commission's Nevada Test Site (NTS) in southern Nevada. The shot, "Sedan", displaced more than 12 million short tons (11 teragrams) of soil and resulted in a radioactive cloud that rose to an altitude of 12,000 ft (3.7 km). The radioactive dust plume headed northeast and then east towards the Mississippi River.

The first PNE blast was Project Gnome , conducted on December 10, 1961 in a salt bed 24 mi (39 km) southeast of Carlsbad, New Mexico. The explosion released 3.1 kilotons (13 TJ) of energy yield at a depth of 361 meters (1,184 ft) which resulted in the formation of a 170 ft diameter, 80 ft high (52 by 25 m) cavity. The test had many objectives. The most public of these involved the generation of steam which could then be used to generate electricity. Another objective was the production of useful radioisotopes and their recovery. Another experiment involved neutron time-of-flight physics. A fourth experiment involved geophysical studies based upon the timed seismic source. The blast, unintentionally, vented radioactive steam while the press watched. Only the last objective was considered a complete success. The partly developed Project Coach detonation experiment, that was to follow adjacent to the Gnome test, was then cancelled.

Over the next 11 years 26 more nuclear explosion tests were conducted under the U.S. PNE program. Funding quietly ended in 1977. Costs for the program have been estimated at more than (US) $770 million.

The final PNE blast took place on May 17, 1973, under Fawn Creek, 76.4 km north of Grand Junction, Colorado. Three 30 kiloton detonations took place simultaneously at depths of 1,758, 1,875, and 2,015 meters. It was the third nuclear explosion experiment intended to stimulate the flow of natural gas from "tight" formation gas fields. If it was successful, plans called for the use of hundreds of specialized nuclear explosives in the western Rockies gas fields. The previous two tests had indicated that the produced natural gas would be too radioactive for safe use. After the test it was found that the blast cavities had not connected as hoped, and the resulting gas still contained unacceptable levels of radionuclides. The concept that stove burners in California might soon emit trace amounts of blast radionuclides into family homes did not sit well with the general public. The contaminated well gas was never channeled into commercial supply lines.

The radioactive blast debris from 839 U.S. underground nuclear test explosions remains buried in-place and has been judged impractical to remove by the DOE's Nevada Site Office.

Table of Plowshare tests

The U.S. conducted twenty-seven PNE shots in conjunction with other, weapons-related, test series. These are annotated under the 'Note' column.

See also

• Chagan: a Soviet Plowshare-type test

References

• United States Nuclear Tests, July 1945 through September 1992 (DOE/NV-209 [Rev.14]).
• Bruce A. Bolt, "Nuclear Explosions and Earthquakes: The Parted Veil" (San Francisco, CA: W. H. Freeman and Company, 1976). ISBN 0-7167-0276-2
• Richard L. Miller, Under the Cloud: The Decades of Nuclear Testing (Woodlands, TX: Two Sixty Press, 1999). ISBN 1-881-04305-3
• Chuck Hansen, U.S. Nuclear Weapons: The Secret History (Arlington, TX: Aerofax, Inc., 1988). ISBN 0-517-56740-7
• Chuck Hansen, The Swords of Armageddon: U.S. Nuclear Weapons Development Since 1945 (CD-ROM).
• National Cancer Institute / Radioactive I-131 from Fallout website. See "Background" link.
• "Estimated Exposures and Thyroid Doses Received by the American People from Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests", A Report from the National Cancer Institute. Contained in the Executive Summary is the map Figure 1 - Per capita thyroid doses resulting from all exposure routes from all test.
• Stephen I. Schwartz, ed., Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940, (Washington, D.C.: Brookings Institution Press, 1998). ISBN 0-8157-7773-6
• "Focused Evaluation of Selected Remedial Alternatives for the Underground Test Area" (DOE/NV-465), April 1997, Environmental Restoration Division, Nevada Operations Office, U.S. Department of Energy.