Semipalatinsk Test Site

Semipalatinsk Test Site
Near Kurchatov in Kazakhstan
The 18,000 km2 expanse of the Semipalatinsk Test Site (indicated in red), attached to Kurchatov (along the Irtysh river), and near Semey, as well as Karagandy, and Astana. The site comprised an area the size of Wales
Coordinates	50°07′N 78°43′E / 50.117°N 78.717°E / 50.117; 78.717
Type	Nuclear test site
Area	~6,950 sq mi (18,000 km2)
Site information
Operator	Soviet Union
Status	Inactive
Site history
In use	1949 – 1991
Test information
Subcritical tests	not known
Nuclear tests	456 (340 underground and 116 aboveground)

The Semipalatinsk Test Site (STS or Semipalatinsk-21), also known as "The Polygon", was the primary testing venue for the Soviet Union's nuclear weapons. It is located on the steppe in northeast Kazakhstan (then the Kazakh SSR), south of the valley of the Irtysh River. The scientific buildings for the test site were located around 150 km west of the town of Semipalatinsk (later renamed Semey), near the border of East Kazakhstan Province and Pavlodar Province with most of the nuclear tests taking place at various sites further to the west and south, some as far as into Karagandy Province.

The Soviet Union conducted 456 nuclear tests at Semipalatinsk from 1949 until 1989 with little regard for their effect on the local people or environment. The full impact of radiation exposure was hidden for many years by Soviet authorities and has only come to light since the test site closed in 1991. The site has been described as "The world's worst radiation hotspot".

From 1996 to 2012, a secret joint operation of Kazakh, Russian, and American nuclear scientists and engineers secured the waste plutonium in the tunnels of the mountains.

The site was selected in 1947 by Lavrentiy Beria, political head of the Soviet atomic bomb project (Beria falsely claimed the vast 18,000 km² steppe was "uninhabited").Gulag labour was employed to build the primitive test facilities, including the laboratory complex in the northeast corner on the southern bank of the Irtysh River. The first Soviet bomb test, Operation First Lightning (nicknamed Joe One by the Americans) was conducted in 1949 from a tower at the Semipalatinsk Test Site, scattering fallout on nearby villages (which Beria had neglected to evacuate). The same area ("the experimental field", a region forty miles west of Kurchatov city) was used for more than 100 subsequent above-ground weapons tests.