Sensitivity of an antineutrino monitor for remote nuclear reactor discovery

Antineutrinos from a nuclear reactor comprise an unshieldable signal, which carries information about the core. A gadolinium-doped, water-based Cherenkov detector has been investigated for detection of reactor antineutrinos for midfield remote reactor monitoring for nonproliferation applications. Two independent reconstruction and analysis pathways have been developed and applied to a number of representative reactor signals to evaluate the sensitivity of a kiloton-scale, gadolinium-doped Cherenkov detector as a remote monitor prototype. The sensitivity of four detector configurations to nine reactor signal combinations was evaluated for a detector situated in Boulby Mine, close to the Boulby Underground Laboratory in the UK. It was found that a 22-m detector with a gadolinium-doped, water-based liquid scintillator fill is sensitive to an approximately 3-GWth reactor at a standoff of approximately 150km within 2 years in the current reactor landscape. A larger detector would be required to achieve a more timely detection or to monitor smaller or more distant reactors.