Abstract: A power oscillation monitoring system and method for indicating instability of a nuclear reactor. The monitoring system facilitates monitoring reactor instability and maintaining a nuclear reactor in the stable state. In one embodiment, the monitoring system is implemented in a computer workstation having memory and a processor. The workstation is electrically coupled to neutron detectors, and a period based algorithm and a confirmation density algorithm are stored in the workstation memory. The processor contains a Period Based Algorithm (PBA) and a Confirmation Density Algorithm (CDA). Under the control of the system the PBA algorithm evaluates the periodicity of the neutron detector output signals to identify the presence of density waves in the reactor. The CDA utilizes the PBA output signals to identify confirmation density, which is the fraction of active neutron detectors in the core that reach a target successive oscillation period confirmation count.

Abstract: A method for modeling linear control systems that are asymptotically stable provided that any initial deviation is within a definite bound is described. The method includes the steps of generating a parametric model of the quasi steady state system, generating a time-invariant parametric mapping function, using the system model, to relate a system setpoint parameter at a system setpoint function to an input process parameter implicit in a system implicit parameter, and generating an interface protocol to adjust the time-invariant parametric mapping function to account for any time-dependent variations in the relative performance between the input process parameter and the implicit system parameter.

Abstract: A computer-based power oscillation detection system and method for detecting, monitoring and indicating thermal-hydraulic stability margin in a nuclear reactor is provided. A group of neutron flux detectors is distributed throughout the reactor core, in contiguous relation to the reactor fuel assemblies, with each flux detector providing an output signal indicative of the power density of the portion of the core adjacent to the detector. A computer-based system processes the detector output signals utilizing a period based algorithm that employs an oscillation detection counting function wherein a count corresponding to the level of periodicity of the signal is determined. Since a representative oscillation count for each reactor stability state usually only occurs on the order of several minutes for a single detector signal, a unique simulated decay ratio algorithm reduces the time required to obtain a representative count by processing the group of detector signals spread throughout the core.