Abstract: In a method and apparatus for reducing the effects of frequency burst noise and noise spikes accompanying a random pulse signal, pulses with an amplitude above a high threshold or below a low threshold are eliminated, with the remaining pulses of intermediate amplitude being statistically filtered. The statistical filter compares the current pulse count rate signal to maximum and minimum statistical limits generated from the recent average value of the pulse count rate using Poisson statistics, and clamps the output to the limit which is exceeded. If the pulse count rate is between the statistical limits, it is used as the output pulse count rate signal. If the statistical limits are exceeded for a designated interval indicative of a true change in the pulse count rate, clamping of the output signal is overridden so that the true change in pulse count rate can be tracked. Statistical filtering is resumed when the current pulse count rate is again within the statistical limits.

Abstract: A nuclear reactor power monitor utilizes radiation sensors, and a microprocessor implementing alpha-beta tracker equations. The use of alpha-beta tracker equations results in good noise suppression and fast follow capability. Therefore, alignment of the reactor power monitor is simplified and transients in the power level of a nuclear reactor can be detected.

Abstract: A method of determining the operability of a source range detector located adjacent a nuclear reactor in which the source range detector generates a count corresponding to the neutrons emitted by the reactor when the reactor is operating within the source range and a predetermined voltage is applied across the electrodes of the detector, the detector being subject to destruction when the reactor power level is above the source range and the predetermined voltage is applied across its electrodes.

Abstract: An inadvertent approach to criticality in a nuclear fueled electric power generating unit is detected and an alarm is generated through on-line monitoring of the neutron flux. The difficulties of accurately measuring the low levels of neutron flux in a subcritical reactor are overcome by the use of a microcomputer which continuously generates average flux count rate signals for incremental time periods from thousands of samples taken during each such period and which serially stores the average flux count rate signals for a preselected time interval. At the end of each incremental time period, the microcomputer compares the latest average flux count rate signal with the oldest, and preferably each of the intervening stored values, and if it exceeds any of them by at least a preselected multiplication factor, an alarm is generated.