Local oscillation monitor in a nuclear reactor

Purpose: To rapidly inform operators with the occurrence of local oscillations in a nuclear reactor by automatically processing local power signal (LPRM signal). Constitution: Signals from LPRMs disposed at an equal interval between fuel assemblies for detecting the local power of nuclear reactor are removed with noise components, and then sent by way of an A/D converter and an averaging device to a subtractor. In the subtractor, the deviation value between the LPRM signal and an average value signal is calculated and the maximum value and the minimum value are determined in a comparator and sent to a calculation device, where a peak-to-peak (p-p) value is determined and stored in the memory and, at the same time, compared with a set value in the comparator. If the p-p value exceeds the setting value, p-p value of other LPRM signal is read out from the memory, calculated in the comparator, and an intermediate bundle between the LPRM of the maximum oscillation value and the setting value is estimated as an oscillation bundle, which is displayed in a CRT and informed to operators. (Kamimura, M.)