Arctic tundra kept frozen by heat pipes

Alyeska Pipeline Service Co. has awarded McDonnell Douglas Corp. a $13 million contract to build nearly 100,000 heat pipes for the trans-Alaska pipeline. The heat pipes are Cryo-Anchor soil stabilizers (see Gas Abstr. 29, 73-0686) designed to prevent thawing of permafrost around pipe supports for elevated portions of the line. These passive soil-refrigeration devices utilize an anhydrous ammonia process, with no moving parts or external power. Advantages include low overall cost, ease of installation, high reliability, versatility, adaptability to various supports, recoverability at end of short-term projects, prevention of gradual degradation and irrevocable losses of land and structures, and the possibility of retrofitting to correct developing problems.