Reactor's rhymes with:
reactors, reactors, actor's, actors, actors', contractors', detractors, factors, factors', reactors, refractors, tractors
Reactor's sounds like:
racetrack, racetracks, racketeers, reactors, register's, registers, registrars, registries, resistors, restores, roasters, rochester's, roister's, roosters, rosters, royster's