REACTIVITY MEASURING METHOD FOR REACTOR, MEASURING METHOD FOR MODERATOR TEMPERATURE COEFFICIENT AND MEASURING DEVICE OF MODERATOR TEMPERATURE COEFFICIENT

摘要

PROBLEM TO BE SOLVED: To obtain the reactivity of a reactor by excluding the effects of switching amplification ranges. SOLUTION: Neutron flux signal constituted by measuring neutron flux in a reactor is amplified with an amplifier and the signal form the amplifier is sampled at a specified interval and converted to digital data with an A/D converter. In calculating the reactivity using the data (n), whether amplification range switching at the amplifier is done or not is decided. For this decision, the ratio between a data n(t+) and data n(t-) at two steps before is obtained and in the case the ratio is within a predetermined range of range switching decision, it is decided that execution of amplification range switching took place. In this case, the data n(t+) is corrected to be data n'(t+) before the amplification range switching, an intermediate date n(t) is calculated by interpolation by using the data n'(t+) and the data n(t+) before amplification range switching, and by using these data, the reactively is obtained.