NNSA’s Defense Nuclear Nonproliferation Research and Development Program drives the innovation of technical capabilities to detect, identify, and characterize foreign nuclear weapons development activities. To achieve this, NNSA leverages the unique capabilities of the national laboratories and the NNSA nuclear security enterprise to perform research, conduct technology demonstrations, and develop prototypes for operational scenarios.
As a critical element in nuclear weapons development, NNSA’s nonproliferation research and development improves U.S. national capabilities to detect, find, and characterize special nuclear material production activities by developing advanced in-place, near-field, and remote sensing technologies.
Nuclear reactors can be monitored by measuring the large number of antineutrinos they produce. Antineutrinos are subatomic particles that are impossible to shield and provide clues to a reactor’s current operating status and power level, potentially a long distance from the reactor. This gives the United States insight into a reactor’s plutonium production potential.
However, to monitor foreign reactors from a distance, these large detectors must be buried underground to avoid cosmic radiation, which contributes to background noise that interferes with the antineutrino signal. Still, some components of cosmic radiation affect even underground detectors and also potentially interfere with a range of other rare-event particle physics experiments.
NNSA researchers have recently designed and constructed a transportable high-energy neutron detection system to overcome this problem. The system is used to measure background noise from high-energy neutrons, allowing researchers to account for interference in measurements when monitoring nuclear reactors.
By making the spectrometer transportable, researchers can use the same detector repeatedly to measure high-energy neutrons at many different locations. Through this measurement the background noise to the antineutrino reactor signal can be more accurately estimated, potentially improving the determination of the reactor operating status and power level.
Experts from University of California, Berkeley; Lawrence Livermore National Laboratory; Sandia National Laboratories; and Lawrence Berkeley National Laboratory contributed to the development of the detection system. Their work was presented at the American Physical Society’s meeting in April. See the full presentation.