| 摘要 |
PURPOSE:To prevent the exposure to radiation and the closure of a drain pipe during the maintenance operation of a detector, by employing a bubble type liquid level meter as a detector with the drain pipe shared as a bubble tube. CONSTITUTION:An air purge meter 2 is connected to a drain pipe 1 and air is released at the tip of a drain pipe on the drain receiving 5 side by always supplying air or always closing a drain valve 4. When the drain pipe comes to sink into a leaking water 7 from a tank 6, the pressure in the pipe 1 rises by a value equivalent to a heat, which enables the detection of a leak by checking the rise in the pressure with a pressure detector 8. Still at this point, air is supplied continuously while the tip of the drain pipe is set downward and hence, no leaked water 7 flows into the pipe 1. In addition, a waster liquor collected into a drain receiver 5 can be transferred to a drain receiving tank 3 by closing an air purge main valve 9 with the valve 4 kept open. This can prevent the exposure to radiation otherwise caused by a radioactive waste liquor in the tank 6 during the maintenance operation of the detector 8 for water leakage and also prevent the closure of the drain pipe when the leaking water has a coagulating property as well.
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