Land surface cleanup of plutonium at the Nevada Test Site

The Nevada Test Site (NTS) covers approximately 3300 km2 of high desert and is located approximately 100 km northwest of Las Vegas, Nevada. Soil contaminated by plutonium exists on the NTS and surrounding areas from safety tests conducted in the 1950s and 1960s. About 150 curies of contamination have been measured over 1200 hectares of land surface. Most contamination is found in the top 5 cm of soil but may be found as deep as 25 cm. The cost of conventional removal and disposal of the full soil volume has been estimated at over $500,000,000. This study is directed toward minimizing the volume of waste which must be further processed and disposed of by precisely controlling soil removal depth. The following soil removal machines were demonstrated at the NTS: (1) a CMI Corporation Model PR-500FL pavement profiler, (2) a CMI Corporation Model TR-225B trimmer reclaimer, (3) a Caterpillar Model 623 elevating scraper equipped with laser depth control, (4) a Caterpillar Model 14G motor grader equipped with laser depth control, (5) a Caterpillar Model 637 auger scraper, and (6) a XCR Series Guzzler vacuum truck. The most effective removal technique tested was the pavement profiler, which provided for dust control and precisely removed thin layers of soil. Soil removal with the motor grader and paddle scraper generated unacceptable dust levels, even after the soil was extensively watered. The vacuum truck was ineffective because of its limited intake volume which is a function of its small intake size, its weak intake force, and the tendency of its filters to clog