Find the antineutrino signal: MPIK scientists Thierry Lassere (left) and Anthony Onillon discussing the Double Chooz data. (Courtesy: R. Lackner/MPIK)

Scientists have measured antineutrino emissions from spent nuclear fuel for the first time, demonstrating that monitoring efforts need not stop when the reactors do. This is important because although independent nuclear safeguarding agencies have long used antineutrino emissions to glean information on reactor operations, previous detection schemes only worked when the reactors were running. Now, however, members of the Double Chooz collaboration have shown that it is possible to detect residual antineutrino emissions during a complete reactor shutdown – including from spent fuel stored in cooling pools.

Like neutrinos, antineutrinos are tiny, nearly massless fundamental particles that come in three flavours: electron, muon and tau.…