Year
2012
Abstract
Antineutrino detection has been demonstrated to provide verification of commercial reactor operation and fissile material content for nuclear safeguards. Previous antineutrino detectors have required underground deployment locations and significant passive neutron and gamma shielding to reduce backgrounds from cosmic-ray showers. The resulting requirement for a several square-meter, belowground deployment location might limit the application of this otherwise non-intrusive monitoring technology to the existing reactor fleet. In this submission, we report on the recent development and deployment of a technology which has the potential to dramatically reduce the footprint of antineutrino detectors and to allow operation above ground. We have developed a segmented scintillation-based design that uses integrated readout of standard organic plastic scintillator and ZnS:Ag/ 6 LiF neutron detection screens. This design provides unambiguous particle identification of the positron and neutron final-state products of an antineutrino interaction, thereby allowing for significant rejection of backgrounds. A small 4-unit prototype has been deployed at the San Onofre Nuclear Generating Station in both above and below ground locations. After initial testing inside of a passive shield, we have found that the added background rejection allows this detector technology to function without the need for external passive shielding. This has allowed our overall footprint to be substantially reduced: the detector and associated equipment are fully contained within a single electronics rack. Our estimates suggest that a full system that is able to fully address the needs of a reactor monitoring regime would require only a modest increase in the detector mass and deployed footprint.