Leak Locating in Bruce NGS-A Steam Generators Using Gas Tracer Techniques

Abstract

In 1981, Ontario Hydro requested development of a leak locating technique capable of locating a 0.5 kg.h'l heavy water leak within 72 h of access to the steam generator head. A gas tracer technique has been developed to the point where it can now be used in the station to locate such leaks. The technique consists of pressurizing the shell side to 450 kPa with a sulphur hexafluoride (SF6) air mixture and sampling on the tube side. To speed up the search, a multi-tube sampler is used to simultaneously sniff a number of tubes. The technique as proposed requires a man to enter the steam generator head, but can be adapted for use from outside the steam generator head. The development equipment and procedures required to complete a search are described.