WATCHMAN: A Remote Reactor Monitor and Advanced Instrumentation Testbed

Abstract

The remote detection of undeclared nuclear reactors, which could be used for production of material used to make nuclear weapons, is a key goal for global nuclear security. To address this challenge, WATCHMAN is beginning construction in Boulby Underground Laboratory, in the UK. WATCHMAN aims to demonstrate the ability to monitor nuclear reactors at distances of tens of kilometers or farther, called far-field monitoring. The first phase of the experiment will consist of a kiloton-scale gadolinium-doped water Cherenkov detector to detect anti-neutrinos coming from the Hartlepool Nuclear Power Station, located at a distance of 25 km from Boulby. The predicted dwell time required for determining that one reactor core is turning on-and-off in the presence of another reactor core is about 10 months. In addition to reactor monitoring, WATCHMAN will also act as an Advanced Instrumentation Testbed for next-generation neutrino detectors.