Sandia National Laboratories is home to the United States’ only operational pulsed nuclear reactor capable of a comprehensive range of transient nuclear fuels testing. The Annular Core Research Reactor (ACRR) was specially designed to provide high power pulses (up to 300-MJ) in very short amounts of time (6-millisecond pulse-width), which allows the ACRR to compete with purpose-built facilities for transient nuclear fuels testing.
The ACRR has historically played a role in transient nuclear fuels testing, including space nuclear reactor, liquid metal fast reactor and light-water reactor fuels. Due to a large, dry central cavity in the reactor, a wide array of fuel and coolant types and sizes can be tested to accident conditions to determine the failure behavior and mechanisms.
Typical fuel testing sequence with fuel heating, clad ballooning, clad melting, and fuel rupture.
The ACRR programmed pulse shape is superimposed.
NESL / ACRR Capabilities Include:
- A large, 5-meter high by 21-centimeter diameter dry central cavity for experimental packages.
- Over 8000-Joules per gram of uranium-235 in the test sample can be deposited in 6-milliseconds for a prototypic system.
- The energy spectrum in the central cavity can be tailored to the experiment, allowing for more prototypic conditions over all reactor types.
- The reactor can be operated in steady state, pulse, and programmable transient modes, ensuring that time profiles for accident scenarios can be closely matched.
- An essentially flat axial power profile of nearly 1-meter can be achieved for larger experiments.
- A large high bay with adequate room for auxiliary and support equipment.
Post irradiation examination of liquid metal reactor fuel after clad failure and fuel relocation
that was tested to failure in the ACRR.