Leaks detection in the amplifier boxes of underwater cables

The aim of this work is to detect leaks inside tight boxes which will be immersed in the bottom of the sea at a 4000 m depth. Radioactive sodium in the form of CO3Na2 in aqueous solution is used as tracer. The method consists in placing the box inside a pressure cell filled up with the active solution and submitting the box to a pressure of 400 kg/cm2. After washing with acetone and water, the activity of the box is measured. Any anomalous activity indicates the penetration of the active solution inside the box. (J.S.)