Discerning whether a nuclear reactor is being used to also create material for nuclear weapons is difficult, but capturing and analyzing antimatter particles has shown promise for monitoring what specific nuclear reactor operations are occurring, even from hundreds of miles away. Researchers have developed a detector that exploits Cherenkov radiation, sensing antineutrinos and characterizing their energy profiles from miles away as a way of monitoring activity at nuclear reactors. They proposed to assemble their device in northeast England and detect antineutrinos from reactors from all over the U.K. as well as in northern France.