B Reactor can take a tour of the reactor by advance reservation. The reactor was designed and built by E. I. du Pont de Nemours and Company based on experimental designs tested by Enrico Fermi at the University of Chicago, and tests from the X-10 Graphite Reactor at Oak Ridge National Laboratory. It was designed to operate at 250 megawatts (thermal). The reactor occupies a footprint of (about and is tall, occupying a volume of . The reactor core itself consisted of a graphite box measuring occupying a volume of and weighing . It was penetrated horizontally through its entire length by
National Atomic Energy Commission reactor was built (1957), the RA-1 Enrico Fermi. The 335-MWe Atucha I designed by Germany's (Siemens) was completed in 1974. In 1984 the 600-MWe Embalse designed by Canadian CANDU started its commercial operation. In 1995 CNEA's functions where divided into newly created separate organizations such as the Nuclear Regulatory Authority ("Autoridad Regulatoria Nuclear - ARN"), which supervises nuclear safety in the country, and the "Nucleoeléctrica Argentina - NASA", the company that operates the two completed nuclear power reactors. Today, CNEA mainly focuses on research and development of nuclear and related technologies. In 2001 the original 1956 Directory structure of a