The reactor period is a measure of the rate of reactor power increase;
the shorter the period the faster the rise. Ten neutron-measuring
channels, covering the full range from source level to 150 percent of
maximum power, measure neutron intensity (flux level) and its rate of
change. These data are continuously transmitted to the reactor operator
and the automatic control and safety system. Too fast a rate of change,
or shorter than a safe period, will automatically “scram” the reactor.