Atomics International

Atomics International
Company type	Division
Industry	Nuclear technology, Nuclear reactor development
Predecessor	Atomic Energy Research Department (AERD)
Founded	1948
Founder	North American Aviation
Fate	Merged into Rockwell International; later absorbed into Rocketdyne division
Headquarters	Canoga Park, California, United States
Area served	United States
Products	Sodium-cooled nuclear reactors (Sodium Reactor Experiment), Systems for Nuclear Auxiliary Power (SNAP) reactors, coal gasification technology
Parent	North American Aviation (later Rockwell International)

Atomics International operated as a branch of North American Aviation (which later merged into Rockwell International) dedicated to pioneering nuclear technology and reactor development for both governmental and commercial applications. The division marked several significant achievements, such as designing, constructing, and running California’s inaugural nuclear reactor in 1952, delivering the first commercially-generated nuclear power in the United States in 1957, and deploying the nation’s first nuclear reactor into space in 1965.

The team at Atomics International engineered a range of commercial nuclear reactors, beginning with the Sodium Reactor Experiment (SRE) and progressing to compact reactor designs like the Systems for Auxiliary Nuclear Power (SNAP-10A). Although some nuclear accidents occurred at the Santa Susana Field Laboratory, these initiatives showcased notable advancements in nuclear technology. Nevertheless, waning enthusiasm for nuclear energy prompted the division to pivot toward alternative energy ventures such as coal gasification and to gradually discontinue its reactor design and testing operations.

Eventually, Atomics International was consolidated with the Rocketdyne division under Rockwell International. Except for certain test zones at Santa Susana, most of its facilities were either dismantled, decontaminated, or repurposed. This evolution mirrored shifts in corporate strategy and adaptation to changes within the energy sector.

Company history

Following World War II, interest in nuclear power surged among both U.S. government agencies and the public. In 1948, North American Aviation formed the Atomic Energy Research Department (AERD) to manage its nuclear research and development activities. AERD constructed and operated a 5-watt thermal aqueous homogeneous reactor in Downey, California, which became the state’s first functioning nuclear reactor in 1952. The department was rebranded as the Atomics International division of North American Aviation in 1955.

SRE – Sodium Reactor Experiment

Atomics International concentrated on advancing commercial nuclear reactor technology by creating a sodium-cooled reactor. Sodium was selected due to its excellent heat transfer capabilities, low melting point, and reduced operating pressure compared to water, which minimized the necessity for heavy piping and specialized containment structures typical of high-pressure water reactors.

Utilizing its expertise in nuclear systems, Atomics International designed and operated the Sodium Reactor Experiment (SRE). On July 12, 1957, this reactor became the first in the United States to deliver electricity to a commercial power grid, supplying energy to Moorpark, California. In July 1959, a malfunction caused blockage in cooling channels that led to partial melting of 13 fuel elements; after repairs, the reactor resumed operation until it was permanently shut down in 1964.

The company also developed demonstration reactors cooled by sodium and organic fluids for the Hallam Nuclear Generating Station (Nebraska) and the Piqua Nuclear Generating Station (Ohio), respectively. The Hallam project employed metallic sodium with a graphite moderator while Piqua used an organic coolant system; both encountered technical difficulties and were decommissioned after short periods of operation.

SNAP – Systems for Nuclear Auxiliary Power

During the mid-1950s, Atomics International was appointed as the lead contractor for the U.S. Government’s compact nuclear reactor initiative under the Systems for Nuclear Auxiliary Power (SNAP) program. To support this project, the Santa Susana Field Laboratory expanded its specialized infrastructure. Following the successful deployment of the SNAP 10A reactor in 1965, the government discontinued the program, leaving several government-owned sites on location. In 1966, the U.S. Department of Energy established the Liquid Metal Information Center—later renamed the Energy Technology Engineering Center (ETEC)—to continue research on liquid metal technologies, utilizing many of the former SNAP facilities.

Additional nuclear energy initiatives

At Santa Susana Field Laboratory, Atomics International operated the Atomics International Hot Lab (which was later known as the Rockwell International Hot Lab), where fuel rods were dismantled to aid SNAP reactor research and development, as well as processing nuclear fuel rods from commercial reactors. The company also pioneered a coal gasification technique employing molten salt technology.

As interest in nuclear research waned, Atomics International merged with other Rockwell divisions in 1978 to create the Energy Systems Group, maintaining its operations as a subdivision. By 1984, its remaining functions were absorbed into Rockwell’s Rocketdyne division. Nuclear research activities ended by 1989, with non-nuclear operations ceasing by 1998. Rocketdyne was acquired by The Boeing Company in 1996; Boeing subsequently sold it to United Technologies Corporation in 2005, which incorporated it into Pratt & Whitney Rocketdyne. Boeing retained ownership of the Santa Susana Field Laboratory site and remained responsible for environmental remediation. The Hamilton Sundstrand division of United Technologies inherited the residual nuclear technical expertise from Atomics International.

Facilities and operations

Atomics International was initially based in Downey before relocating to various locations within California’s San Fernando Valley, particularly in Canoga Park. Due to handling radioactive substances, comprehensive records exist detailing historical activities at each facility.

Downey Facility

The Atomic Energy Research Development Group commenced operations at North American Aviation’s plant on Lakewood Drive in Downey, California, where it developed and operated the Water Boiler Neutron Source, an aqueous homogeneous reactor producing four watts of power. This reactor was decommissioned and transferred to the Santa Susana Field Laboratory in December 1955. After decontamination, the Downey reactor buildings were converted into office spaces and eventually handed over to the City of Downey; these structures were later demolished to make way for commercial developments.

Vanowen Boulevard Facility

Situated at Owensmouth Avenue and Vanowen Street in Canoga Park, adjacent to the Rocketdyne Canoga complex, this location specialized in fuel development for SNAP reactors and radiochemical processes. It also housed two small aqueous homogeneous reactors—the 5-watt L-47 and 10-watt L-77—which were both shut down by 1960 with all radioactive materials removed thereafter. Subsequently, Atomics International relocated its headquarters to De Soto Avenue while Rocketdyne assumed control of the Vanowen facility, which was demolished in 2007.

De Soto Avenue Facility

Originally established in 1959 as the headquarters for Atomics International in Canoga Park, this site housed the 10-watt L-77 aqueous homogeneous reactor along with nuclear fuel fabrication, gamma irradiation, and radiochemistry laboratories. Operations involving radioactive materials were discontinued by the mid-1990s. Presently, Aerojet Rocketdyne owns and manages this property.

Thompson-Ramo-Wooldridge Facility

Nuclear research activities were conducted at leased premises from Thompson-Ramo-Wooldridge Inc., which was renamed TRW in 1965. This facility was situated at the intersection of Fallbrook Avenue and Roscoe Boulevard in Canoga Park, an area now known as West Hills.

Santa Susana Field Laboratory (SSFL), Area IV Facility

From 1953 through 1989, Atomics International carried out nuclear reactor development, support operations related to nuclear technology, and non-nuclear research and development at the Energy Technology Engineering Center (ETEC), located within the Simi Hills of Ventura County at SSFL Area IV.

These activities led to contamination by chemical and radioactive substances. The cleanup responsibility falls to the U.S. Department of Energy (DOE) under a 2010 Administrative Order on Consent (AOC), which mandates restoration of the 290-acre site to background contamination levels. In 2009, the EPA launched a $41.5 million investigation to evaluate radiological contamination.

Nuclear Reactor Development and Testing

Between 1954 and 1980, numerous nuclear reactors and critical test assemblies were constructed and operated at SSFL Area IV.

Advanced Epithermal Thorium Reactor

Commissioned in 1960 for the Southwest Atomic Power Association, this reactor examined twenty different core configurations before its program concluded in 1972.

Homogeneous Water Boiler-type Reactors

Atomics International developed low-power aqueous homogeneous reactors utilizing enriched uranyl sulfate solutions. The L-54 model was implemented by various U.S. universities and international institutions, including Japan, where it became known as Japan Research Reactor-1 (JRR-1). After its decommissioning in 1970, JRR-1 has been preserved as a museum exhibit.

Sodium Reactor Experiment (SRE) program

Operating from 1957 until 1964, the SRE achieved a milestone by producing the first commercial nuclear-generated electricity in the United States in 1957. A partial fuel meltdown occurred in 1959 but was successfully repaired, allowing operations to continue until 1964.

Systems for Nuclear Auxiliary Power (SNAP) program

Atomics International acted as the prime contractor for the AEC’s SNAP initiative (1955–1973), which focused on creating compact nuclear reactors for applications in space, terrestrial, and marine environments. Approximately $850 million was invested in developing SNAP reactors, including SNAP-10A—the sole U.S. nuclear reactor ever launched into space. Facilities dedicated to SNAP testing were established at ETEC within SSFL Area IV.

SNAP nuclear reactors tested at SSFL Area IV
Designation	Name	Date	Power (kWth)	SSFL Building
SER	SNAP Experimental Reactor	Sep 1959 – Dec 1960	50	010
SDR / S2DR	SNAP Developmental Reactor	Apr 1961 – Dec 1962	65	024
S8ER	SNAP 8 Experimental Reactor	May 1963 – Apr 1965	600	010
SNAP 10A FS-3	Duplicate of launched SNAP 10A FS-4	Jan 1965 – Mar 1966	38	024
S8DR	SNAP 8 Developmental Reactor	Jun 1968 – Dec 1969	600/1000	059

Nuclear support operations

Approximately twenty structures were built within Area IV to handle radioactive materials essential to reactor programs—covering fuel fabrication, storage, reprocessing, measurement, calibration, and waste management tasks. As of January 2010, only the Radioactive Materials Handling Facility remains operational to assist DOE cleanup activities.

ETEC – Energy Technology Engineering Center

The Energy Technology Engineering Center (ETEC) specialized in the non-nuclear evaluation of components intended for heat transfer in nuclear reactors utilizing liquid metals. Managed by Atomics International as a division under contract with the U.S. Department of Energy, ETEC operated from 1966 through 1998 at the Santa Susana Field Laboratory (SSFL).

Ownership and licensing

Atomics International, functioning as a division within a private enterprise, conducted commercial operations by providing products and services to corporations, academic institutions, and international governments while simultaneously performing research and development for the U.S. Government. The organization possessed licenses for handling radioactive materials both in commercial contexts and as a government contractor. Activities involving radioactive substances owned by the Department of Energy were overseen by the DOE directly, without requiring separate permits. Facilities such as DeSoto and Vanowen maintained operational permits issued by either the Nuclear Regulatory Commission (NRC) or California’s Radiological Health Branch. At SSFL, four buildings held NRC licenses: Rockwell International Hot Lab (4020), L-85 reactor building (4093), Nuclear Materials Development Facility (4055), and Fast Critical Experiment Laboratory (4100). Radiation exposure thresholds were more stringent at NRC-regulated locations, with staff frequently transferring between DOE-managed and NRC-licensed sites.

Additional information

The DOE’s former Energy Technology Engineering Center Project website contains comprehensive historical records and updates on site remediation efforts.
The California Department of Toxic Substances Control SSFL Site Investigation offers current information on ongoing cleanup activities.
An interactive timeline presents nuclear-related operations within SSFL Area IV.
The 2005 Historical Site Assessment provides detailed operational history and building-specific insights for SSFL Area IV.
Additionally, the U.S. Environmental Protection Agency has compiled a separate Historical Site Assessment for SSFL Area IV.

External links

U.S. Department of Energy (DOE): official Energy Technology Engineering Center (ETEC) Cleanup at SSFL website – outlines DOE’s remediation of Atomics International facilities within ETEC/SSFL Area IV.
Official Boeing Santa Susana Field Laboratory (SSFL) Cleanup website – details Boeing’s environmental cleanup initiatives at ETEC/Area IV.