SNAP-2 Image Gallery

The SNAP-2 reactor was an early American fission power plant, to be paired with a mercury Rankine power conversion system (seen at left), to be used for high-powered applications such as space stations.

While it never flew as the SNAP-2, it shared a core configuration with the SNAP-10A used in SNAPSHOT. Additionally, several test reactors were built to verify reactor behavior and conduct materials studies.

Technical Artist Renderings

Reactor Details

Mission Applications

SNAP Critical Assembly

The first step in the experimental series for the entire SNAP program, the SNAP Critical Assembly was a series of tests to investigate the nuclear properties of he fuel in a variety of reactor conditions, including launch failure leading to accidental immersion. It went through four incarnations, SCA-1 to SCA-4.

SNAP Experimental Reactor (SER)

The SNAP Experimental Reactor was far closer to the final flight design than the SCA series, but many questions about reactor configuration remained. This, combined with a need to easily access the fuel post-irradiation for testing, led to a slightly different configuration to the flight design.

SER informed SNAP-2, SNAP-10, and SNAP 8.

SNAP-2 Development Reactor

The last in the SNAP series of nuclear test reactors, the SNAP-2 Development Reactor was designed to finalize the flight configuration for what was by then the SNAP-2/10A reactor core and primary coolant loop. It was installed in the same location as the SNAP Experimental Reactor.

SNAP-2/10B and SNAP Improvement Program

The SNAP-2/10B and SNAP Improvement Program were outgrowths of the experience gained during preparations for, and execution of, the SNAPSHOT mission. These components were designed to improve the nuclear, thermodynamic, and materials properties of the SNAP2/10 core.


The SNAP TRANsient Reactor Test was a destructive nuclear test, in which a modified SNAP-2/10A was made to destroy itself to show a worse-than-worst-case scenario for accident planning.

The YouTube channel Plainly Difficult has done an excellent video on the SNAPTRAN experiment (also a good source of information on criticality accidents, industrial disasters, and the like).

Environmental Testing

Hg Rankine Power Conversion System (CRU)

CRU Testing