Peaceful Nuclear Explosions
(updated July 2010)
- The USA and Russia have investigated and trialled the use of nuclear explosions for civil engineering purposes, though only one significant construction resulted: a dam in Kazakhstan.
- Russia has used nuclear explosions to extinguish major gas well fires.
- Some 150 experiments spanned 1957-75 in the USA and 1965-89 in the USSR.
- PNEs will be banned under the Comprehensive Nuclear Test-Ban Treaty when it enters into force.
Following the military use of nuclear weapons in August 1945, attention turned to harnessing nuclear power in a more controlled manner for electricity generation. However, at the same time there was considerable investigation and testing of peaceful nuclear explosions (PNE) by both the USA and USSR.
From the outset it was realized that thermonuclear blasts (as distinct from fission) would have the least potential for radioactive fallout. However, along with early weapons tests, some PNE tests did contribute to atmospheric radioactivity, and some test sites now pose a radiological hazard.
Applications of PNEs
Possible applications for peaceful nuclear explosions include:
- Large-scale excavation to create reservoirs, canals and ports.
- Stimulating oil and gas recovery.
- Creating cavities for underground oil, gas or waste storage.
- Extinguishing gas field fires.
- Space propulsion.
- Interception of potentially dangerous Near Earth Objects (asteroids, etc).
- Recovering oil from oil shale.
- Energy production via molten fluorides underground producing steam for electricity.
- Breaking up copper and phosphate ore preparatory to mining.
Of these, the first four have been tested (and even applied in some cases by the USSR) while the remaining five have been investigated but not tested.
A total of 151 PNE experiments have been carried out by both the USA (27) and the USSR (124 plus 32 tests that helped develop explosive devices used in PNEs). No other country has ever carried out a PNE testa and there are currently no moves towards a resumption of tests.
Some advocates claim that PNEs would be the most economically feasible method of carrying out large terrestrial engineering projects, and that they provide one of only a few feasible means of managing large gas field fires and destroying chemical weapons. However, a significant concern is that the widespread commercial introduction of PNEs would represent a security risk – increasing the number of nuclear explosives and their locations, along with civilian accessibility.
PNE programs resulted in some international collaboration. Following an approach from the Soviet Union to the USA, the first of four bilateral discussions on PNEs was held in Vienna in April 1969. Subsequent meetings were held in Moscow (1970), Washington (1971), and Vienna (1975). In the course of these meetings with scientists from the US Plowshare Program (see next section), Soviet scientists unveiled some of the technical details of their first few PNE experiments as well as general plans for several applications they were developing. In the early 1970s, the Soviet Union also provided information on the scope and technical results of some of their activities through a series of meetings on PNEs at the International Atomic Energy Agency (IAEA) in Vienna.
PNEs will be banned under the Comprehensive Nuclear Test-Ban Treaty (CTBT) when it eventually enters into force (see section below on Treaties governing the use of PNEs).
USA: Plowshare Program
The Plowshare Programb was the name given to the main US efforts to promote and develop nuclear explosions for peaceful purposes during the 1960s and 1970s, concluding in 1975.
Project Plowshare was formally established in mid-1957 by the former US Atomic Energy Commission (AEC). Later in the year, the AEC carried out the first underground nuclear explosion at the Nevada Test Site – the Rainier event, of 1.7 kilotonc. Results from this validated theoretical concepts and gave impetus to Plowshare. In total, 27 PNE tests consisting of 35 separate blasts were conducted between December 1961 and May 1973 in the USA as part of the program.
Most of the Plowshare proposals were for large-scale civil engineering projects involving massive earthmoving, specifically to improve the shipping lanes linking the Atlantic and the Pacific. At least one was intended to widen the Panama canal, another aimed to create a new sea-level waterway through Nicaragua. Two other geo-engineering proposals were for a harbour and a highway and rail cutting. Other Plowshare proposals and tests sought in various ways to exploit other applications listed above, particularly gas and oil recovery.
From a scientific and engineering perspective the program was by most accounts successful; however, economic viability was questionable and no commercial operation involving PNEs has resulted in the USA or been carried out by a US organization. Over time, scientists learned how to shape charges to provide the desired engineering result and also almost completely to eliminate the release of radioactive materials. However, not all explosions proceeded as planned and in certain cases, notably the Sedan blast (see below), significant radioactive releases occurred.
An early proposal was Operation Chariot, accepted by the AEC in 1958, to build a harbour at Point Hope, Alaska to facilitate the transport of coal and oil. The harbour was to be about a 1.5 km long and 0.8 km wide. One scheme for its development involved the use of five chained thermonuclear explosions. The plan was permanently shelved in 1962 due to local opposition from the Inupiat Eskimos and conservationists concerned about the health of the local ecosystem which the Inupiat relied upon for food. The economic viability was also questioned.
In 1959 the Oilsands study looked at using a PNE for extracting oil from Canada's Athabasca tar sands, and the Olishale study looked at shattering oil shales to enhance oil recovery from them, this being taken further in the 1967 Bronco study focused in Colorado. A 1971 study looked a using a PNE to harness geothermal energy.
In 1963, the Caryall study on the use of PNEs to excavate a cutting through the Bristol Mountains near Amboy was carried out by the California State division of Highways and Santa Fe Railway. The 3.4 km cut was designed to accommodate both the Interstate 40 highway and a new rail line. About 22 nuclear explosions would have been required, ranging in size from 20 to 200 kilotons, providing a total explosive force of 1730 kilotons. The plan was cut from the US budget in 1965.
After Chariot, almost all excavation research to 1970 was then focused on building a sea-level canal across the Central American isthmus in support of the Atlantic-Pacific Interoceanic Canal Study Commission to replace the Panama canal. As part of this project, six cratering experiments were carried out at the Nevada Test Site over 1961-68, including Sedan described below. Part of the purpose was to establish means to reduce radioactive contamination from such blasts.
PNE tests in the USA
The first full test of the Plowshare Program was Project Gnome, which took place in December 1961, near Carlsbad, New Mexico, in a bedded salt formation. International observers were in attendance. The device was placed in a tunnel 360 metres underground and the resulting 3.1 kiloton blast created a cavity 20 metres wide and 50 metres high. The explosion was supposed to be self-sealing, but a brief burst of radioactive material was released. Some six months after the test, a new access tunnel was drilled and crews entered to survey the results. They found a blue, green and violet landscape of melted salt stalactites, and the temperature of the cavity was still above 60°C.
The second PNE test under project Plowshare was also one of the largest. The Sedan blast took place at Yucca Flat on the Nevada Test Site in July 1962. It was a shallow underground explosion designed to test the cratering potential of PNEs for the creation of artificial lakes and reservoirs. A thermonuclear device was inserted 194 metres into the desert alluvium. The resulting 104 kiloton explosion created a dome 90 metres high which then exploded outwards displacing more than 10 million tonnes of material to create a crater 100 metres deep and 390 metres wide. Of all Plowshare nuclear tests, Sedan created the most radioactive fallout. Twin dust plumes deposited radioactive material downwind, with the highest concentrations in Iowa and South Dakota of more than 0.22 gigabecquerels per square metre.
Three separate PNE tests were carried out to assess the ability of nuclear explosions to stimulate gas production from low-permeability formations. These were Gasbuggy (December 1967, New Mexico: 29 kilotons), Rusilon (September 1969, Colorado: 43 kilotons) and Rio Blanco (May 1973, Colorado: 3 blasts of 33 kilotons each at depths of 1600-2100 metres using charges 195 mm diameter). Rio Blanco also marked the end of the US PNE test program. It was already known that conventional explosions could stimulate production of gas, and the use of nuclear explosives just added to the overall force of the explosion. While the level of gas production from the tests was less than expected, it would have been sufficient to make the process commercially viable if the resulting gas had not been considered too radiologically contaminated by tritium for saled.
Starting with the Gnome test in 1961, Plowshare provided support for scientific experiments, primarily as additions to weapons tests, to look at the possibility of using these high neutron fluxes to produce heavy transplutonic elements well beyond the end of the Periodic Table. The ultimate goal was the use of multiple neutron captures to reach the predicted 'island of stability' at element 114. Between 1962 and 1969, Plowshare supported the design and fielding of five dedicated experiments and 'add-ons' to some 10 weapons tests at the Nevada Test Site in an attempt to reach this elusive goal. Certainly large quantities of some heavy elements were produced, and traces were recovered from the melt zone, e.g. the actinides curium-250 and fermium-257.
USA: Other proposals for the use of PNEs
Not all US concepts for the use of PNEs officially came under the banner of the Plowshare Program. A few other proposals, developed by various organizations, include the potential use of PNEs for space travel and energy production.
PNEs for space travel
Project Orion was the first serious attempt to develop the concept of Nuclear Pulse Propulsion, i.e. using nuclear explosions for spacecraft thrust. It was initiated by the company General Atomics in 1958 and continued until 1965, though impetus for the idea was largely killed off by the signing of the Partial Test Ban Treatye in 1963, which banned nuclear testing in space due to fears over the effects of fallout. The basic concept was to detonate shaped nuclear charges in space behind a spacecraft mounted with a pusher plate and a shock absorber so as to transfer momentum. The principle was shown to be robust, leading to both excellent thrust and impulse characteristics, something quite rare for space propulsion techniques which usually trade one off against the other. It was also well suited for large spacecraft (about 1000 t) since significant mass was required to shield against the effects of radiation.
Electricity from PNEs
One possibility of harnessing nuclear fusion as an energy source was the suggestion of detonating small thermonuclear weapons in an underground cavity and capturing the energy. The Pacer Project, developed at Los Alamos National Laboratories during the mid-1970s, investigated the design and operation of such a system. The original proposal involved the use of low-yield hydrogen bombs, while subsequent proposals advocated simpler fission devices. One variation of the plan called for nuclear devices in the kiloton range to be detonated in an underground cavity at regular intervals of about 45 minutes. The heat would be captured by molten fluoride salts flowing down the chamber wall which would then act as a heat exchange fluid producing steam to drive a turbine for electricity. The early plan envisaged the blast chamber as being inside a salt dome, but later developments called for a fully-engineered vessel. The concept never developed past the planning stage.
USSR: Nuclear Explosions for the National Economy
The USSR equivalent to the Plowshare Program was Nuclear Explosions for the National Economy. It comprised mainly Program 7, Peaceful Nuclear Explosions for the National Economy.
Overall the PNE test regime was much larger than the US effort and concentrated on a more diverse range of applications. Early support for a comprehensive test ban meant that PNE testing didn’t get underway in the USSR until 1965; it then continued right up to 1989, when a moratorium on nuclear weapons testing was implemented. Like Plowshare, the program was originally focused on excavation and oil and gas recovery, but interest in other applications soon emerged.
In 1965, in cooperation with the Oil Production Ministry, Program 7 began field experiments directed at using nuclear explosions to increase oil production, and also planning experiments in salt to produce cavities. The nuclear weapons laboratory at Arzamas-16 near Gorky initially played the major role in adapting military explosions to peaceful applications.
Overall, some 124 PNE tests were carried out at sites throughout the former Soviet Union (80 in Russia, 39 in Kazakhstan, two in Ukraine, two in Uzbekistan and one in Turkmenistan)f. Five PNEs were used for construction of water reservoirs, 25 for constructing underground cavities, mostly in salt and sponsored by the Gas Production Ministry, 21 for stimulating oil and gas recovery, and five for controlling runaway gas well fires. A further 30 or more tests related to developing explosives, hence total of about 156.
Scientifically, Program 7 included 39 tests spread right across the USSR sponsored by the Geology Ministry for deep seismic sounding of the Earth's mantle, from 1971-88. There were also more than a dozen tests over 1975-79 on transplutonic element production, sponsored by the Ministry of Medium Machine Building (responsible for the Soviet weapons program), all 180 km north of Astrakhan.
Chagan: water reservoir
One of the better known tests is the January 1965 test at Chagan, on the edge of the Semipalatinsk Test Site in Kazakhstan. Designed to test the suitability of PNEs for creating reservoirs, it was the first experiment carried out in the Soviet PNE program and, at 140 kilotons, the largest of any PNE test. The device was placed in a 178 metre deep hole in the dry bed of the Chagan River so that the crater lip would dam up the river during periods of high flow. The blast formed a crater 400 metres across and 100 metres deep with a lip height of 20 to 38 metres. Subsequent to the blast, a channel was cut into the crater allowing it, and the reservoir behind it, to fill up with water. Initially the crater itself held 6.4 gigalitres of water and reservoir contained some 10 gigalitres, but subsidence later reduced this figure by about 25%.
Radiation dose levels in the 1990s were reported as about one hundred times background levels at the lip of the crater, and the crater water was about 100 times drinking water standard for radionuclides, though 100-150 metres away dose levels were at background level. It was estimated that some 20% of the radioactive products from the test escaped the blast zone, and some were detected over Japan. This resulted in complaints from the USA, which thought the explosion was a weapons test and in breach of the 1963 Partial Test Ban Treaty.
Kama-Pechora canal project
In 1965, another project became the primary focus of the Soviet nuclear excavation program – the construction of a canal to divert water from the Pechora River in the Arctic region into the Volga River basin and Caspian Sea, which had been depleted over the preceding 35 years as a result of climatic anomalies and municipal and agricultural uses of water from the Volga-Kama River system. Water from the north would be diverted through a 112 km canal into the Kama and thence south to the Volga River and the Caspian Sea.
It was proposed to use nuclear explosives to dig the central 65 km of the canal where it passes through higher elevations. This would involve several hundred devices, firing up to 20 at a time, with aggregate yield of up to 3000 kilotons. After initial successful tests – Tel'kem 1 & 2 – approval was given in 1969 to proceed with the project. The next stage of the project involved a major thermonuclear test in 1971 – Taiga – in saturated alluvial deposits at the south end of the route, and showed that nuclear excavation would be unsuitable there. By the mid-1980s, plans for the canal were abandoned.
Urtabulak: gas well fire
In 1966, a nuclear explosive was detonated at Urtabulak gas field in Southern Uzbekistan in order to extinguish a gas well fire that had been burning for almost three years and had resisted numerous attempts at control. The gas fountain, which formed at pressures of almost 300 atmospheres, had resulted in the loss of over 12 million cubic metres of gas per day through a 200 mm casing – enough to supply a city the size of St Petersburg. Two 445 mm holes were drilled that aimed to come as close as possible to the well at a depth of about 1500 metres in the middle of a 200 metre thick clay zone. One of these came to within about 35 m of the well and was used to emplace the special 30-kiloton charge which had been developed by the Arzamas weapons laboratory. Immediately after the explosion the fire went out and the well was sealed.
This was the first of five PNEs used for this purpose, and all but one was completely successful in extinguishing the fire and sealing the well. No radioactivity above background levels was detected in subsequent surveys of any of the sites.
Treaties governing the use of PNEs
Article V of the 1970 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) states that the "potential benefits from any peaceful applications of nuclear explosions will be made available to non-nuclear-weapon States Party to the Treaty on a non-discriminatory basis."g
Subsequent to the NPT, the Peaceful Nuclear Explosions Treaty is a bilateral agreement between the USA and the USSR designed to allow the investigation of the potential peaceful uses of nuclear explosions without promoting weapons development. It was signed in April 1976, came into force in December 1990h and governs the use of PNEs until the Comprehensive Nuclear Test-Ban Treaty (CTBT) enters into force.
Under the PNE Treaty, no single explosion may be greater than 150 kilotons and no group explosion may consist of an aggregate yield greater than 1500 kilotons. In addition, signatory parties are committed to sharing information about explosions, allowing access to the blast site and otherwise not hindering the verification process. The treaty governs permissible underground nuclear explosions which may be carried out for peaceful purposes. A major driver for establishment of the treaty was the Russian desire not to be misunderstood in relation to the Partial Test Ban Treatyi when constructing the Kama-Pechora canal project, which would have involved many explosions (the US Plowshare Program being finished by then).
Under the Comprehensive Nuclear Test-Ban Treaty (CTBT), the use of PNEs will be prohibited. However China has consistently pushed for this condition to be changed, and while it has signed (but not yet ratified) the treaty, it has requested that the issue be reconsidered 10 years after it enters into force. The CTBT opened for signature in September 1996 and will enter into force when all countries listed in Annex 2 of the treaty have signed itj.
a. India claimed that its 1974 nuclear test was a PNE, but it was not part of any civil program. [Back]
b. The Plowshare Program name derives from a prophetic Bible passage (Micah 4:3) about beating swords into plowshares as nations turn away from warfare. [Back]
c. The force of explosions is measured in kilotons: the approximate equivalent of one thousand tonnes of TNT, set by international agreement as 4.184 GJ. For comparison, the Hiroshima bomb was about 15 kt, Nagasaki about 25 kt. [Back]
d. There has been a resurgence of interest in drilling near the Rusilon site. As of August 2009, there were 84 permits issued within 5 km of the site, 11 of which were within 1.5 km. Currently there is a 0.8 km radius imposition on drilling near the test site, but there is talk of this being lifted. A 2005 report from the US Department of Energy (DOE) states that the radiation levels at the site surface and in the groundwater has reduced to background levels. In contrast, the Gasbuggy site is considered a contamination issue as radioactive material, most likely tritium, has migrated through the bedrock. It is currently being monitored as part of a cleanup strategy originally overseen by the US DOE – see page on the Gasbuggy site on the DOE's Office of Environmental Management website (www.em.doe.gov). [Back]
e. The Treaty Banning Nuclear Weapon Tests in the Atmosphere, in Outer Space and Under Water is usually referred to as the Partial Test Ban Treaty, or Limited Test Ban Treaty. It was originally signed by the USA, Soviet Union and United Kingdom on 5 August 1963 and came into force on 10 October 1963. [Back]
f. Figures for number of PNE tests and applications should only be taken as approximate, given the lack of agreement between sources. Discrepancies between sources could be a result of several factors, for example: secrecy surrounding PNE research; more than one simultaneous explosion taking place in some PNE tests; and some tests being carried out alongside weapons testing. [Back]
g. Article V of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) states:
Each Party to the Treaty undertakes to take appropriate measures to ensure that, in accordance with this Treaty, under appropriate international observation and through appropriate international procedures, potential benefits from any peaceful applications of nuclear explosions will be made available to non-nuclear-weapon States Party to the Treaty on a non-discriminatory basis and that the charge to such Parties for the explosive devices used will be as low as possible and exclude any charge for research and development. Non-nuclearweapon States Party to the Treaty shall be able to obtain such benefits, pursuant to a special international agreement or agreements, through an appropriate international body with adequate representation of non-nuclear-weapon States. Negotiations on this subject shall commence as soon as possible after the Treaty enters into force. Non-nuclear-weapon States Party to the Treaty so desiring may also obtain such benefits pursuant to bilateral agreements.
The full text of the NPT is available on the International Atomic Energy Agency's website (www.iaea.org). [Back]
h. The Treaty between the United States of America and The Union of Soviet Socialist Republics on Underground Nuclear Explosions for Peaceful Purposes (the Peaceful Nuclear Explosions Treaty, PNET) was a companion treaty to the Treaty on the Limitation of Underground Nuclear Weapon Tests, also known as the Threshold Test Ban Treaty (TTBT), to cover PNEs carried out underground. The TTBT was signed in 1974, but not ratified until after the PNET had been agreed in 1976. Although both treaties did not enter into force until 1990, both parties in 1976 agreed to observe the limit of 150 kilotons. [Back]
i. See Note e above. [Back]
j. The CTBT will enter into force once all the 44 states listed in Annex 2 of the treaty have signed and ratified it. Three have not yet signed it: India, Pakistan and North Korea; and six others have signed the treaty, but not yet ratified it: China, Egypt, Indonesia, Iran, Israel and the USA. [Back]
M. D. Nordyke, The Soviet Program for Peaceful Uses of Nuclear Explosions, Lawrence Livermore National Laboratory, UCRL-ID-124410 Rev 2 (September 2000)
Plowshare Program, Office of Scientific and Technical Information, US Department of Energy