| 摘要 |
Acoustic waves are sensed in contact with or near the plant at at least two points (1, 2, 3, 4) whose position is accurately determined with respect to the monitored region. The order of arrival of the acoustic waves at the sensing points (1, 2, 3, 4) is determined and this order is compared with a predetermined order corresponding to a phenomenon occurring in the monitored region. An alarm is triggered if the order of arrival corresponds to the predetermined order. The apparatus includes an encoding logic (9), a comparator (10) and a monostable circuit (12) triggering the alarm. The invention is particularly applicable to monitoring nuclear reactors in operation. |
