Subterrene
A subterrene (/sʌbˈtɛriːn/) is an alleged patented nuclear-powered tunnel boring machine that melts through rock using a compact nuclear reactor, vitrifying the surrounding material into a smooth glass-lined tunnel as it advances — eliminating all spoil, muck, and surface trace of the excavation. The concept was developed at Los Alamos National Laboratory in the early 1970s and is documented through United States government patents and technical reports compiled by researcher Richard Sauder.
Design and patents
The United States Atomic Energy Commission filed the first nuclear subterrene patent in 1972 (U.S. Patent No. 3,693,731). Two additional patents followed in May 1975, filed by the United States Energy Research and Development Administration. The machine works by circulating liquid lithium from a compact nuclear reactor to the tunnel face at approximately 2,000 degrees Fahrenheit, melting the rock. The molten rock flows around the machine's periphery and solidifies into a smooth, structurally sound, watertight glass lining. The cooled lithium circulates back along the machine's exterior, helping cool the vitrified walls, before returning to the reactor to repeat the cycle — "the nuclear subterrene slices through the rock like a nuclear powered, 2,000 degree Fahrenheit earthworm, boring its way deep underground."
Sauder estimated the boring rate at approximately 300 feet per day based on figures cited in the technical literature. The military-industrial complex also explored using ultrasound to pulverise rock for tunnel boring — a distinct technology from nuclear melting.
The 1972 patent explicitly notes the principal operational advantage: no muck or tailings are produced. Unlike conventional TBMs, which generate enormous volumes of spoil requiring removal by conveyors, trains, or trucks, the subterrene absorbs the excavated material into the tunnel lining itself — making the tunneling activity and the finished tunnel "very hard to detect, for the simple reason that there would not be the tell-tale muck piles or tailings dumps that are associated with conventional tunneling activities."
Cost analysis
A 1973 Los Alamos technical report titled Systems and Cost Analysis for a Nuclear Subterrene Tunneling Machine concluded that nuclear subterrenes were "very cost-effective" compared to conventional TBMs, with potential savings of $850 million through 1990. A separate 1975 analysis by A.A. Mathews found 12 percent savings for 15.5-foot tunnels and 6 percent savings for 20.5-foot tunnels in Southern California conditions.
Current status
The nuclear subterrene patents were filed, a handful of technical documents were published — "and then the whole thing just sort of faded away. Or did it?" as Sauder noted. No public record confirms that an operational nuclear subterrene was ever built. However, Phil Schneider, who claimed 17 years' experience in deep underground military base construction, described machines matching the subterrene concept in operational use: "They don't bore, they literally vitrify and melt the rock... a very sophisticated laser melting... reduces the rock to a powder and then melts the remaining rock as a coating on the inside of the base." A September 1983 Omni article described a Los Alamos nuclear tunnel boring machine that "burrows through deep underground rock, heating it to a molten state (magma), which cools after the Subterrene moves on. The result is a tube with a smooth, glazed lining that can be used for the high-speed transport shuttles that link the sub-base complexes."
Lunar application
In 1986, Los Alamos proposed adapting the nuclear subterrene concept for use on the Moon, where such machines would create maglev transport tunnels "hundreds or thousands of kilometers long" beneath the lunar surface — a plan that, if implemented, would represent a direct extension of the terrestrial DUMB transit network to an extraterrestrial body.
Etymology
The word subterrene is also recorded as an English adjective meaning "underground" or "subterranean."