Measurement of impurity concentration in sodium by automatic plugging indicator

In order to improve the reliability of operation and to confirm how the operating conditions, especially the sodium flow rate, affect the measuring accuracy, an automatic plugging indicator was designed and tested. This indicator has specially shaped orifices by which the perfect choking of impurity is prevented from the orifice passage. By the experiment on its characteristics, the followings have been confirmed. (1) A stable automatic operation is obtained successfully by the plugging characteristic of the orifices. (2) The optimum operating region of the sodium flow rate to improve the measuring accuracy is obtained. (auth.)