Annular Core Research Reactor (ACRR)
Neutron/Gamma Research, Testing, and Qualification for National Security, Science, and Advanced Technology
The Annular Core Research Reactor (ACRR) is a unique nuclear reactor facility, regarded as a national treasure due to its unmatched attributes and capabilities. It is a pool-type reactor with large dry testing cavities, operating in steady-state, pulse, and tailored transient modes.
ACRR also features radiation spectrum modifying filters for customized neutron and gamma radiation environments to complement irradiation testing and experimental research.
ACRR’s primary mission it to qualify and certify components for the nuclear deterrent. The ACRR facility is dedicated to delivering on time, at scale, and with capabilities necessary to match the mission needs of the 21st century.
Capabilities
Radiation Effects Testing
Provides mixed neutron and gamma environments for testing electronics, materials, and systems exposed to radiation.
Flexible Reactor Modes
Supports high-power, short-duration reactor pulses to study rapid energy deposition, system response, and safety margins.
Tailored Spectrum Radiation Environments
Neutron and gamma spectra can be modified using cavity inserts and experimental configurations to meet specific test requirements.
Key Features
- Annular core geometry
- 9” dry Central Cavity
- 20” dry Fueled-Ring External Cavity
- Epithermal Neutron Flux
- Large test facility for thermal neutron flux
- Up to 15” items at the bottom of the cavity and 25” on top
- Supported experiments can include hazardous items, such as powered electronics, explosives, flowing fluids, and fissionable materials.
Radiation Environments
- Fast, epithermal, and thermal neutron spectra
- Mixed neutron/gamma fields
- Spectrum-tailored environments using moderators and absorbers
- Operating Modes: Steady-state, Pulse/Pulse Reduced Tail, and Tailored Transient
- Highly repeatable pulse conditions
Radiation environments are supported by validated computational modeling and dosimetry.
Primary Applications
Radiation Effects Testing
- Electronics and semiconductor devices
- Sensors and instrumentation
- Aerospace and space-system components
Materials
Irradiation
- Structural and functional materials
- Radiation damage and performance studies
- Benchmarking of materials models
Transient & Safety Research
- Reactor kinetics experiments
- Fuel and system response studies
- Code validation and safety margin analysis
Specialized
Programs
- Space reactor technology research
- National security applications
- Select isotope and activation studies (historical and exploratory)
- DOE and NNSA programs
- Department of War sponsors
- Industry partners
- Academic collaborators (via sponsored or interagency agreements)
Access is programmatic and coordinated through Sandia and DOE sponsorship. ACRR is not an open-access user facility, but collaboration pathways exist for qualified projects aligned with mission needs.
- Experiment design and feasibility analysis
- Neutron and gamma dosimetry
- MCNP-based modeling and spectrum characterization
- Controlled execution and post-test data support
Radiation Characterization White Papers