| 摘要 |
PURPOSE:To execute exactly a measurement by considering the speed of sound corresponding to a water temperature by installing a distance detecting body and a sound speed detecting body to a freely liftable sensor supporting base by a specified arrangement, and deriving an external size by using the speed of sound calculated from the time measured by both the detecting bodies. CONSTITUTION:An external size measuring instrument 10 of a channel box 3 is constituted of an external size measuring means 11 and an operating means 21, and the means 11 is constituted by installing a sensor supporting base 16 so as to be freely liftable on a guide body 17 fixed and provided on a side face 1a of a used fuel storage pool 1, and installing a distance detecting body 13 and a sound speed detecting body 15 to the base 16. Also, the detecting body 13 is constituted by providing a suitable number of ultrasonic sensors 12 provided on a straight line, in a shape of L so that its transmission is reflected each other from the box 3, the detecting body 15 is constituted by providing a pair of ultrasonic sensors 14 so that one executes a transmission and the other executes a reception, and an external size of the box 3 is derived by correcting a distance measured by the detecting body 13, by the speed of sound by the detecting body 15. |
