| 摘要 |
PURPOSE:To detect a water level in the pressure vessel of a nuclear reactor accurately, by covering the outer circumference of a heating unit with a sheath having a thermocouple and moreover, providing a water level detector having its outer circumfrence protected by a protective tube to the pressure vessel of the nuclear reactor. CONSTITUTION:A sheath 37 is provided around an electrically insulating material 36 having a coil-shaped heating unit 35 and a thermocouple 38 is embedded on its surface and moreover, water level detectors 34a-34d consisting of a protective tube 39 fitted onto the outside of the sheath 37 are provided to the pressure vessel of a nuclear reactor through a measuring nozzle. Plural thermocouples 38 are provided in the axis direction of the detector 34 and are set on a display device through cables. In thus constituted water level detector, the water level is measured by detecting a part lowering electromotive force of the thermo couple because heat generated by the unit 35 is deprived only at a part where the water level detector is in contact with water 50 when the water flows into the pressure vessel of the reactor, and the electromotive force of the thermocouple provided at this part is dropped down suddenly. |
