Before revision: The physicist John Archibald Wheeler, working for DuPont at the time, together with Enrico Fermi were able to identify that the drop in the neutron flux and the consequent shutdown was caused by the accumulation of 135Xe in the reactor fuel.
After revision: The physicists John Archibald Wheeler, working for DuPont at the time, and Enrico Fermi were able to identify that the drop in the neutron flux and the consequent shutdown was caused by the accumulation of 135Xe in the reactor fuel.