Advances towards readily deployable antineutrino detectors for reactor monitoring and safeguards

The large flux of neutrinos that leaves a nuclear reactor carries information about two quantities of interest for safeguards: the reactor power and fissile inventory. Our SNL/LLNL collaboration has demonstrated that antineutrino-based nuclear reactor monitoring is feasible using a relatively small cubic scale detector made of Gadolinium loaded liquid scintillator at tens of meters standoff from a commercial Pressurized Water Reactor, deployed in an underground gallery that lies directly under the containment. Recently we have investigated several technologies paths that could allow such devices to be more readily deployed in the field - of particular concern to reactor operators and safeguards practitioners is the flammability of the Gd doped liquid scintillator. In addition, many PWR facilities do not have an available underground gallery to provide the screening of muon induced backgrounds. As a result, we have developed and fielded three new detectors: a low cost, non-flammable water based design; a robust solid-state design based upon plastic scintillator; and a smaller cryogenic detector based on ultra-high purity Germanium. All three of these technologies have been deployed at our below-ground facility at the San Onofre Nuclear Generating Station in southern California. We first present an overview of the use of antineutrinos in reactor monitoring. We then explain the detection mechanism based on inverse beta decay and the dominant sources of above-ground background that would contaminate this signal. Next, we discuss conceptual ideas under consideration for a future aboveground detector. Separate sections are devoted to describe the design, construction and deployment of each of our three new technologies that have already been deployment. We discuss the various levels of sensitivity to the reactor antineutrino signature that each of these detectors was able to demonstrate and the tradeoffs that accompany them.