page_title: Atomics International
section_title: SRE – Sodium Reactor Experiment
hierarchical_section_title: Atomics International / Company history / SRE – Sodium Reactor Experiment
caption_attribution_description: English: The City of Los Angeles presented this decorative resolution to Atomics International on May 20, 1965 following the successful launch and operation of the SNAP-10A nuclear reactor.
context_page_description: Atomics International was a division of the North American Aviation company which engaged principally in the early development of nuclear technology and nuclear reactors for both commercial and government applications. Atomics International was responsible for a number of accomplishments relating to nuclear energy: design, construction and operation of the first nuclear reactor in California, the first nuclear reactor to produce power for a commercial power grid in the United States and the first nuclear reactor launched into outer space by the United States.
  Atomics International undertook the development of nuclear reactors soon after being established: a series of commercial nuclear power reactors beginning with the Sodium Reactor Experiment and a range of compact nuclear reactors culminating with the Systems for Auxiliary Nuclear Power SNAP-10A system. Both efforts were successful, despite nuclear accidents at the Santa Susana Field Laboratory, but overall interest in nuclear power steadily declined. The division transitioned to non-nuclear energy-related projects such as coal gasification and gradually ceased designing and testing nuclear reactors.
context_section_description: The Sodium Reactor Experiment was the result of Atomics International initially focusing on developing and commercializing reactor technology by undertaking the design of a nuclear power reactor capable of producing electricity on a commercial basis. Atomics International decided sodium was a more appropriate nuclear reactor coolant than water. Sodium was chosen because it has excellent heat transfer properties, has a low operating pressure at typical reactor temperatures and it has a relatively low melting point. When used as a coolant for a nuclear reactor, water requires heavy piping since at the high reactor temperatures, water is kept under pressure. In the event of an accident, the sudden breach of the high temperature water system (among other things) necessitates a special containment vessel to capture the released pressure.
  Experience gained from conducting basic nuclear technology development provided Atomics International with the experience and practical knowledge necessary for the design, construction and operation of the Sodium Reactor Experiment nuclear reactor. On July 12, 1957 the Sodium Reactor Experiment became the first nuclear reactor in the United States to produce electrical power for a commercial power grid by powering the nearby city of Moorpark. In July 1959 an accident  where the narrow internal cooling channels within the reactor fuel assemblies became obstructed by an organic contaminant causing 13 of 43 reactor core fuel elements to partially melt. Atomics International personnel repaired the reactor which was restarted in September, 1960 and operated until 1964. The company subsequently designed and developed a concept demonstration sodium cooled nuclear power unit for the Hallam Nuclear Generating Station in Nebraska and a concept demonstration organic (Santowax) cooled nuclear power unit for the Piqua Nuclear Generating Station, in Ohio  as experimental demonstration projects for the Atomic Energy Commission. The Piqua reactor was a 45.5 MWe organically moderated and cooled reactor while Hallam was a liquid metal cooled reactor using metallic sodium with graphite as the moderator. Both Hallam and Piqua were beset by technical problems and operated only a few years before being permanently shut down.
caption: On May 20, 1965, the City of Los Angeles recognized Atomics International on the occasion of the successful SNAP-10A mission
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