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Nevada Test Site

Nevada Test Site

The Nevada Test Site (NTS) is one of two locations (the South Pacific being the other) at which the United States has conducted the majority of its nuclear weapons tests. The site was chosen for weapons testing in December 1950 by President Harry S. Truman and originally named the Nevada Proving Ground. The first test of a nuclear weapon was carried out at the site in January 1951 when a B-50 bomber dropped a bomb for the first of five tests in "Operation Ranger."

The Nevada Test Site is located 65 miles (105 km) northwest of Las Vegas. It occupies 1,350 square miles (3,497 km2), an area slightly larger than the state of Rhode Island. Nellis Air Force Base and the Tonopath Test Range surround the site on three sides.

Over 3,500 people are employed by NTS, 1,500 of whom work on the site itself. The site's annual budget is about $450 million, a large percentage goes for weapons testing and a small percentage which is spent on the radioactive waste storage facility at nearby Yucca Mountain .

The first nuclear tests at the site were conducted over an area known as Frenchman Flat. Between 1951 and 1962, a total of fourteen atmospheric tests were carried out in this area to determine the effect of nuclear explosions on structures and military targets. Ten underground tests were also conducted at Frenchman Flat between 1965 and 1971.

Since 1971, most underground tests at the site have been conducted in the area known as Yucca Flat. These tests are usually carried out in wells 10 ft (3 m) in diameter and 600 ft (182 m) to one mile (1.6 km) in depth. On an average, about twelve tests per year are carried out at NTS.

Some individuals have long been concerned about possible environmental effects of the testing carried out a NTS. During the period of atmospheric testing, those effects (radioactive fallout , for example) were relatively easy to observe. But the environmental consequences of underground testing have been more difficult to determine.

One such consequence is the production of earthquakes, an event observed in 1968 when a test code-named "Faultless" produced a fault with a vertical displacement of 15 ft (5 m). Such events are rare, however, and of less concern than the release of radioactive materials into groundwater and the escape of radioactive gases through venting from the test well.

In 1989, the Office of Technology Assessment (OTA) of the United States Congress carried out a study of the possible environmental effects from underground testing. OTA concluded that the risks to humans from underground testing at NTS are very low indeed. It found that, in the first place, there is essentially no possibility that any release of radioactive material could go undetected. OTA also calculated that the total mount of radiation a person would have received by standing at the NTS boundary for every underground test conducted at the site so far would be about equal to 1/1000 of a single chest x-ray or equivalent to 32 minutes more of exposure to natural background radiation in a person's lifetime.

See also Groundwater pollution; Hazardous waste; Nuclear fission; Radiation exposure; Radioactive decay; Radioactivity

[David E. Newton ]



"New Bomb Factory to Open Soon at Test Site." Bulletin of the Atomic Scientists 46 (April 1990): 56.

"Press Releases Don't Tell All." Bulletin of the Atomic Scientists 46 (January-February 1990): 45.

Slonit, R. "In the State of Nevada." Sierra (September-October 1991): 90101.


Office of Technology Assessment. The Containment of Underground Nuclear Explosions. OTA-ISC-414. Washington, D.C.: U.S. Government Printing Office, 1989.

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