Scientists with the Double Chooz collaboration have measured, for the first time, the weak antineutrino emission that continues after a nuclear reactor is switched off, according to ScienceDaily. The research was published in Physical Review Letters and led by Anthony Onillon and Thierry Lasserre of the Max-Planck-Institut fur Kernphysik in Heidelberg, Germany.
The observation was made at the Chooz nuclear power plant in northern France, where the Double Chooz detector is located underground about 400 meters from the facility’s two reactor cores. The detector uses more than 30 cubic meters of liquid scintillator, which flashes when an antineutrino interacts inside it.
Researchers analyzed 17.2 days of data collected while both reactor units were fully shut down. During that period, the detector recorded about 100 antineutrino candidate events tied to residual radioactivity in the reactor cores and nearby spent-fuel cooling pools.
The signal matched simulations that accounted for the remaining fuel and the decay of long-lived fission products, providing the first direct experimental confirmation of predictions about antineutrino emissions from shut down reactors and spent fuel. The findings suggest antineutrino detectors could eventually help verify reactor status and track spent-fuel inventories during outages and after shutdown.
Double Chooz was originally designed to study neutrino oscillations and helped measure the neutrino mixing angle theta-13, a key parameter in neutrino physics. The collaboration’s latest result adds another first to the experiment’s record by detecting the faint signal that remains after a reactor goes dark.
