Original sentence: When a reactor’s neutron population remains steady from one generation to the next, the fission chain reaction is self-sustaining and the reactor’s condition is referred to as "CRITICAL".When the reactor’s neutron production exceeds losses, characterized by increasing power level, it’s called "SUPERcritical", and; when losses dominate it’s "SUBcritical" & exhibits decreasing power
Edited sentence: When a reactor’s neutron population remains steady from one generation to the next (creating as many new neutrons as are lost), the fission chain reaction is self-sustaining and the reactor's condition is referred to as "critical".When the reactor’s neutron production exceeds losses, characterized by increasing power level, it is considered "supercritical", and; when losses dominate, it is considered "subcritical" and exhibits decreasing power