Project Plowshare

By exploiting the peaceful uses of the "friendly atom" in medical applications, earth removal, and later in nuclear power plants, the nuclear industry and government sought to allay public fears about nuclear technology and promote the acceptance of nuclear weapons. At the peak of the Atomic Age, the United States Federal government initiated Project Plowshare, involving "peaceful nuclear explosions". The United States Atomic Energy Commission chairman at the time, Lewis Strauss, announced that the Plowshares project was intended to "highlight the peaceful applications of nuclear explosive devices and thereby create a climate of world opinion that is more favorable to weapons development and tests". These tests were to demonstrate that atomic bombs can be used for peaceful purposes, that the atomic sword could be beaten into a plowshare. == Proposals ==

Proposed uses for nuclear explosives under Project Plowshare included widening the Panama Canal, constructing a new sea-level waterway through Nicaragua nicknamed the Pan-Atomic Canal, cutting paths through mountainous areas for highways, and connecting inland river systems. Other proposals involved blasting 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. Project Carryall, proposed in 1963 by the Atomic Energy Commission, the California Division of Highways (now Caltrans), and the Santa Fe Railway, would have used 22 nuclear explosions to excavate a massive roadcut through the Bristol Mountains in the Mojave Desert, to accommodate construction of Interstate 40 and a new rail line. At the end of the program, a major objective was to develop nuclear explosives, and blast techniques, for stimulating the flow of natural gas in "tight" underground reservoir formations. In the 1960s, a proposal was suggested for a modified in situ shale oil extraction process which involved creation of a rubble chimney (a zone in the oil shale formation created by breaking the rock into fragments) using a nuclear explosive. However, this approach was abandoned for a number of technical reasons. Nuclear weapon designs For gas stimulation shots, one problem was extreme conditions. They needed a device with a small diameter on the order of that could withstand extended periods at without refrigeration. Another major problem was "residual tritium". The Rulison shot used an expensive fission explosive. The Miniata shot tested a cheaper and smaller (9 inch diameter) "minimum residual tritium" design device known as Diamond. Notably, Los Alamos Scientific Laboratory also proposed a 9 inch "tritium free" device that would use proton-boron fusion to strongly limit the neutron radiation produced. == Plowshare testing ==

The first Peaceful Nuclear Explosion (PNE) blast was Project Gnome, conducted on December 10, 1961, in a salt bed southeast of Carlsbad, in southeast New Mexico. The explosion released 3.1 kilotons (13 TJ) of energy yield at a depth of which resulted in the formation of a diameter, high cavity. The test had many objectives, the most public of which involved the generation of steam which could then be used to generate electricity. Another objective was the production of useful radioisotopes and their recovery. Yet another experiment involved neutron time-of-flight physics, and a fourth experiment involved geophysical studies based upon the timed seismic source. Only the last objective was considered a complete success. The blast unintentionally vented radioactive steam while the press watched. The partly developed Project Coach detonation experiment that was to follow adjacent to the Gnome test was then canceled. A number of proof-of-concept cratering blasts were conducted; including the Buggy shot of five 1-kiloton devices for a channel/trench in Area 30 and the largest being 104 kiloton (435 terajoule) 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 of soil and resulted in a radioactive cloud that rose to an altitude of . The radioactive dust plume headed northeast and then east towards the Mississippi River. and CER Geonuclear Corporation for the Rio Blanco test. The final PNE blast took place on May 17, 1973, under Fawn Creek, north of Grand Junction, Colorado. Three 30-kiloton detonations took place simultaneously at depths of . If it had been 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; the Rio Blanco test found that the three blast cavities had not connected as hoped, and the resulting gas still contained unacceptable levels of radionuclides. By 1974, approximately $82 million had been invested in the nuclear gas stimulation technology program. It was estimated that even after 25 years of production of all the natural gas deemed recoverable, only 15 to 40% of the investment would be recouped. Also, 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 gas was never channeled into commercial supply lines. The situation remained so for the next three decades, but a resurgence in Colorado Western slope natural gas drilling has brought resource development closer and closer to the original underground detonations. By mid-2009, 84 drilling permits had been issued within a radius, with 11 permits within mile of the site. ==Impacts, opposition and economics==

Operation Plowshare "started with great expectations and high hopes". Planners believed that the projects could be completed safely, but there was less confidence that they could be completed more economically than conventional methods. Moreover, there was insufficient public and Congressional support for the projects. Projects Chariot and Coach were two examples where technical problems and environmental concerns prompted further feasibility studies which took several years, and each project was eventually canceled. Project Plowshare shows how something intended to improve national security can unwittingly do the opposite if it fails to fully consider the social, political, and environmental consequences. It also “underscores that public resentment and opposition can stop projects in their tracks”. Historian Dr. Michael Payne notes that it was primarily changing public opinion, in response to events such as the Cuban Missile Crisis, that drove the protests, court cases and general hostility that ended the oil and gas stimulation efforts. Furthermore, as the years went by without further development and production of nuclear weapons slowed, interest in peaceful applications waned in the 1950s–60s. Cheaper, non-nuclear stimulation techniques suitable for most US gas fields were developed in the following years. As a point of comparison, the most successful and profitable nuclear stimulation effort that did not result in customer product contamination issues was the 1976 Project Neva on the Sredne-Botuobinsk gas field in the Soviet Union, made possible by multiple cleaner stimulation explosives, favorable rock strata and the possible creation of an underground contaminant storage cavity. The Soviet Union retains the record for the cleanest/lowest fission-fraction nuclear devices so far demonstrated. The public records for devices that produced the highest proportion of their yield via fusion-only reactions, and therefore created orders of magnitude smaller amounts of long-lived fission products as a result, are the USSR's Peaceful nuclear explosions of the 1970s, with the three detonations that excavated part of Pechora–Kama Canal, being cited as 98% fusion each in the Taiga test's three 15-kiloton explosive yield devices, that is, a total fission fraction of 0.3 kilotons in a 15 kt device. In comparison, the next three high fusion-yielding devices were all much too high in total explosive yield for oil and gas stimulation: the 50-megaton Tsar Bomba achieved a yield 97% derived from fusion, while in the US, the 9.3-megaton Hardtack Poplar test is reported as 95.2%, and the 4.5-megaton Redwing Navajo test as 95% derived from fusion. == Nuclear tests ==

The U.S. conducted 27 PNE shots in conjunction with other, weapons-related, test series. == Non-nuclear tests ==

In addition to the nuclear tests, Plowshare executed a number of non-nuclear test projects in an attempt to learn more about how the nuclear explosives could best be used. Several of these projects led to practical utility as well as to furthering knowledge about large explosives. These projects included: ==Proposed nuclear projects==

A number of projects were proposed and some planning accomplished, but were not followed through on. A list of these is given here: ==See also==