Distances and Detector Sizes for Neutrino Monitoring: A Survey of 64 Historical Plutonium Production Reactors

The idea of using neutrino detectors to monitor nuclear reactors has been discussed for decades, but it is not always clear what reactor-to-detector distances and detector sizes would be involved. The purpose of this study is to offer some concrete, historically grounded data points: namely, estimates of standoff distances and detector sizes for 64 reactors involved in plutonium production for weapons programs. This data set spans nine countries and 70 years. For each reactor, we estimate the distance from the core to the facility boundary, one conceivable standoff for cooperative monitoring. We also find the distance from the reactor to the nearest international border, the shortest possible standoff for non-cooperative monitoring. We estimate the neutrino detector size required in both cases, considering inverse beta decay and electron scattering channels. Overall, the data set provides a realistic orientation to the distances and detector size scales involved in reactor neutrino monitoring.