Nuclear and Thermonuclear Explosives and their Peaceful Uses

Civilian users consume far more chemical explosives every year than all the armed forces of the world. Nuclear and thermonuclear explosives, although ordinarily conceived of in terms of weapons of war, are likewise applicable to peaceful uses. In fact, most people would be surprised to know that there have been more operational uses of nuclear explosives for peaceful than for warlike purposes : the Soviet Union used them on five separate occasions to extinguish gas-well fires.

The theory of implosion-type and gun-type nuclear fission explosives will be covered, as will tritium boosting, and the Teller-Ulam radiation-implosion multistage thermonuclear explosive.

Applications to be discussed will include civil engineering (earthmoving), the petroleum industry (fracturing, fire extinguishment), and space propulsion (Project Orion).

Slides

Introductory slide with Seaborg quote
The fundamental principle of the nuclear explosive is the conversion of mass to energy. We observe that much more energy is available from a kilogram of deuterium than from one of plutonium, and it's cheaper, too.
The device exploded at Trinity was conceived of as a weapon, a shock to dash cities to rubble and a heat flash to burn them to ash along with their inhabitants. At that time there was no thought of using the "Gadget" for anything but killing large numbers of people rapidly, nor would it have been suitable for anything else.
The "catastrophic success" of Castle Bravo led the weapons designers to an understaning of the flexibility of the Teller-Ulam principle : as Theodore Taylor put it, a device could be made to do practically anything short of spitting out green paint. This opened the door for civilian applications, because of the much lower cost & radioactive residue of thermonuclear explosives with a high proportion of fusion yield. The illustration is defective in one notable point, as it is necessary to stop neutrons from the primary reaching the secondary, or a "fizzle" will occur.
The weapons designers, recalling the Prophecy of Micah (4:3), called their effort to turn their work to the benefit of mankind "Project Plowshare". Most proposed applications, not surprisingly, involved making large holes in the ground, usually for excavation purposes, such as making canals and road cuts, or creating or enlarging harbours. By maximizing the fusion yield and selecting an appropriate depth of burial, dispersion of radioactive debris could be held to a minimum.
Test "Storax Sedan" was a demonstration of cratering at "optimum depth of burial", using an explosive much dirtier than the specialized types being developed under Plowshare, which were not suitable for use as weapons. "Gasbuggy" was one of three attempts (the others being "Rulison", and the three-detonation series "Rio Blanco") to stimulate production of natural gas by "fracking". A related proposed application was in breaking up underground ore bodies for extraction by leaching. "Nougat Gnome" created a cavity in a salt bed, in pursuit of several objectives, including the production of superheavy isotopes, and "Pacer", an alternative to controlled fusion experiments, which would have used underground thermonuclear detonations as a kind of pseudo-geothermal heat source for power plants.
By far the most ambitious peaceful application of nuclear explosives was Project Orion, the effort to create giant spaceships propelled by nuclear shaped charges, which would reach most any destination in the Solar System within a few weeks. One description, based on a comparison of the number of pulse units required with the American nuclear weapons inventory, was "unilateral disarmament in three round trips". A downscaled version was considered for launch as a Saturn V upper stage, but practical considerations and the language of the Moscow (Limited Test Ban) Treaty forestalled this proposal.