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United States United States · Idaho Falls, ID · 43.595, -112.657

EBR-II

EBR-II, a research reactor (fast) in Idaho Falls, ID, United States, with 62.5 MW of thermal power, operated by Argonne West National Laboratory. Decommissioned, first critical in 1961.

It was one of the 340 research reactors the United States has had; 48 remain in operation today. It went critical 19 years after the first research reactor in the United States, CP-1, Chicago Pile 1 (1942). 15 fast research reactors remain in operation today across 6 countries. It is one of 3 research reactors in 1 country that Argonne designed or built.

Country
United States
City
Idaho Falls, ID
Type
Fast
Thermal power
62.5 MW
Operator
Argonne West National Laboratory
Design and construction
Designed and built by Argonne National Laboratory
Status
Decommissioned
First criticality
1961
Purpose
Materials testing

Data: IAEA RRDB · updated on Sep 3, 2026

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