| 摘要 |
PURPOSE:To prevent false detection of leadkage from the main steam pipe by copying with a sharp change in detected temperature at the time of disconnection of a power supply for an air regulator or the like which ventilates a main steam tunnel chamber of a nuclear power plant or the like. CONSTITUTION:A heat quantity released from the main steam pipe 2 into a main steam tunnel chamber 1 is made to flow out into the air by ventilation through ducts 5 and 6 which are connected to an air regulator 4 and the air, respectively. The temperatures on the inlet and outlet sides of each of the ducts 5 and 6 are detected by inlet outlet temperature detectors 20 and 21, respectively, and when the difference temperature exceeds a threshold value, a difference temperature detector 24 generates a detection signal for leakage of the pipe 2. When there happens the discontinuation of a power supply of the regulator 4 or the like, contacts LS5 and LS6 of a temperature detection controller 23 are turned OFF and ON respectively through the intermediary of a timer term relay R2 of a timer TM1 of an air regulator abnormality detector 22 to cope with a sharp change in temperature according to the detector 20 by an alternative temperature memorized in a virtual temperature signal generator 30. Thus, the detector 24 conducts no false detection when power supply for the air regulator or the like is discontinued, while detecting actual leakage without fail. |
