Reactor Power Monitor Utilizing Cerenkov Radiation

Cerenkov light in the central region of a water-moderated reactor has been measured as a function of reactor power. Simple photovoltaic light detectors were used with a recording microammeter. The electrical current responded to a power increment increase with an initial rise proportional to the reactor power. This was followed by an additional increase in current of from 4 to 5% with a time constant of approximately 4 minutes.