United States · Lemont, IL · 43.533, -112.945 (approximate location)

Janus

Janus, a research reactor (tank) in Lemont, IL, United States, with 200 kW of thermal power, operated by Argonne National Laboratory. Decommissioned, first critical in 1964.

It was one of the 340 research reactors the United States has had; 48 remain in operation today. It went critical 22 years after the first research reactor in the United States, CP-1, Chicago Pile 1 (1942). 36 tank-type reactors remain in operation today across 23 countries. Its declared uses include materials testing.

Country

United States

City

Lemont, IL

Type

Tank

Thermal power

200 kW

Operator

Argonne National Laboratory

Status

Decommissioned

First criticality

1964

Purpose

Materials testing

See also: every research reactor in United States · How research reactors work