page_title: Atomics International
section_title: Development and testing of nuclear reactors
hierarchical_section_title: Atomics International / Facilities and Operations / Santa Susana Field Laboratory (SSFL), Area IV Facility / Development and testing of nuclear reactors
caption_attribution_description: 日本語: 日本で最初の研究用原子炉JRR-1竣工を記念して発行された記念切手
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: Between 1954 and 1980 at the Santa Susana Field Laboratory several nuclear reactors were built, tested and operated in Area IV. These included both nuclear reactors and critical test assemblies. A critical test assembly is a very low-power reactor that does not require an active cooling system and frequently requires a separate neutron source to maintain critical neutron flux.
  Advanced Epithermal Thorium Reactor
  The Advanced Epithermal Thorium Reactor was built for the Southwest Atomic Power Association at Building 100 in 1960. The AETR was used to test twenty different reactor core configurations by using an apparatus which supported a range of geometries. The AETR program was terminated in 1972.
  Homogeneous Water Boiler-type Reactors
  Atomics International designed and built a range of low-power (5 to 50,000 watts thermal) nuclear reactors for research, training and isotope production purposes. This aqueous homogeneous reactor type of low-power nuclear reactor used a 93% enriched uranyl sulphate solution held in a critical configuration in a spherical vessel. Reactivity was controlled using an arrangement of control rods within tubes penetrating the reactor vessel. The solution did not boil; rather, neutron and gamma flux caused radiolytic decomposition of water into hydrogen and oxygen in the form of tiny bubbles that gave the impression of boiling.
  One reactor model, the L-54, was purchased and installed by a number of United States universities and foreign research institutions, including Japan. The Japanese Atomic Research Institute renamed theirs Japan Research Reactor-1 (JRR-1) and the government of Japan issued a commemorative postage stamp noting the establishment of Japan's first nuclear reactor in 1957. The reactor was decommissioned in 1970 and is now maintained as a a museum exhibit with a Japanese-language website at Tokaimura, Japan
  Sodium Reactor Experiment (SRE) program
  The Sodium Reactor Experiment (SRE) was an experimental nuclear reactor which operated from 1957 to 1964. On July 12, 1957, its electrical generating system produced the first electricity generated from a nuclear power system to supply a commercial power grid in the United States by powering homes in the nearby city of Moorpark. In July 1959, the narrow internal cooling channels within the reactor fuel rod assemblies became obstructed by an unintended byproduct-produced organic contaminant, causing 13 of 43 reactor fuel elements to partially melt in an incident. Atomics International personnel repaired the reactor, which was restarted in September 1960 and operated with minor incidents until 1964.
  Systems for Nuclear Auxiliary Power (SNAP) program
  The objective of the Systems for Nuclear Auxiliary Power program undertaken in 1955 by the United States was the development of compact, lightweight, reliable atomic electric devices for space, land and sea. The Atomic Energy Commission—AEC (predecessor to the Department of Energy—DOE), was the procurement agency for the Department of Defense (DOD) and National Aeronautics and Space Administration—NASA requirements. The AEC was responsible for developing technologies that would allow the requirement to be fulfilled and for carrying out the initial phases of operational tests. From the period 1955 to 1973 when the program was terminated, approximately $850 million then-years dollars were spent by the United States to develop the SNAP nuclear reactors.
  Atomics International was the prime contractor to the AEC for the development of the SNAP reactors. In the late 1950s to the early 1960s, Atomics International established a number of government-owned facilities to support the SNAP program at the Energy Technology Engineering Center (ETEC) in Area IV of the Santa Susana Field Laboratory (SSFL). The SNAP-10A was the only nuclear reactor launched and flight tested by the United States. The City of Los Angeles issued a proclamation to recognize the accomplishment. The facilities included underground test facilities to test the compact SNAP nuclear reactors, non-nuclear test and support buildings, and a
caption: In 1957, Japan issued this stamp commemorating the completion of their first nuclear reactor. Translation: "The establishment of the first reactor in Japan - 1957"
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