| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a water level detection system which can be additionally installed by small-scaled installation work to existing facilities and has excellent radiation resistance. <P>SOLUTION: According to one embodiment, a water level detection system comprises: a reference gamma ray source 24 which is installed in a water tank 21 in reactor facilities and generates a reference gamma ray; a gamma ray detecting sensor 1 which is disposed at the same height as that of the reference gamma ray source 24 in the vicinity thereof in the water tank 21 and detects gamma rays; a signal processing section 3 to which a gamma ray detecting signal output from the gamma ray detecting sensor 1 is input, performs count processing for defining a detection number of the gamma rays per unit time as a counting rate and outputs the counting rate; a threshold value storage section 5 for storing a threshold value of the counting rate therein beforehand; and a comparison determining section 4 for, in a case where the counting rate output from the signal processing section 3 exceeds the threshold value, determining the gamma ray detecting sensor 1 to be in an exposed state to air from underwater. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
