| 摘要 |
PURPOSE:To monitor neutron flux in a wide range with one amplifier by providing a level diagnostic circuit for a Campbell measuring system circuit and diagnosing a signal level on a basis of a set value to switch gain. CONSTITUTION:The detection signal of the neutron flux detector 101 arranged in a nuclear reactor pressure vessel is inputted to a preamlifier 103 for wide range through a coaxial cable 102. The preamplifier 103 consists of an input-stage amplifier 104 and an amplifier 105 whose gain can be switched, and the output signal is inputted to a pulse measuring system circuit 107 and a Campbell measuring system circuit 108 through coaxial cable 106. A level diagnostic circuit 120 is provided for the Campbell measuring system circuit 108; and if the signal level of a smoothing circuit 118 becomes higher than a set value, the gain of the gain switching amplifier 105 is reduced, and the output display level is lowered. |
