Patent ID: 8576975

Claim:
A method of operating a Boiling Water Reactor, said boiling water reactor having fuel assemblies arranged inside of channels through which coolant flows, comprising: a step of analyzing Local Power Range Monitor signals for oscillatory behavior indicative of neutron flux coupled density wave oscillations; determining if oscillatory behavior beyond a noise level is present in the signals; initiating a first reactor protective corrective action if the oscillatory behavior is determined to be present; if the Local Power Range Monitor signals analyzed in the step of analyzing Local Power Range Monitor signals are not oscillatory beyond noise level, a step of analyzing several channels of high power using a stability program on line at actual operating conditions and checking to determine if neutron flux uncoupled oscillations are possible; and initiating a second reactor protective corrective action while the Local Power Range Monitor signals are not oscillatory beyond noise level if it is determined in the step of analyzing several channels of high power that neutron flux uncoupled oscillations are possible; and repeating at least the step of analyzing Local Power Range Monitor signals if it is determined in the step of analyzing several channels of high power that neutron flux uncoupled oscillations are not possible.