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U.S. Department of Energy
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Detection of leaks in a water-cooled generator stator bar using perfluorocarbon tracers

Technical Report ·
OSTI ID:7023783

A generator stator bar with a suspected leak was removed from the ConEdison Ravenswood power plant and shipped to an independent laboratory for hydraulic pressure testing. The test failed to demonstrate the location and magnitude of leaks. The stator bar was subsequently investigated at Brookhaven's Tracer Technology Center. Pressurization with 3 ppM PMCP (perfluoromethylcyclopentane) in hydrogen as carrier gas revealed a leak close to the turbine end of the generator. The equivalent water leak rate was calculated to be about 1/2 mL per day at 30 psi water pressure. A series of tests was designed to first verify the existence of potential leaks and then to locate these leaks as accurately as possible. Enclosing the bar in a flexible hose, introducing nitrogen gas into the hose and analyzing the hose exhaust with Brookhaven's Dual Trap Analyzer successfully identified the existence of leaks. However, the technique failed to locate the approximation position of the suspected leaks. It was found that diffusion and the existence of a laminar flow regime inside the hose prevented the formation of uniform concentration levels and, hence, consistent readings. Successful leak pinpointing was accomplished by wrapping short sections of the bar in plastic bags. This approach with some suggested improvements is also recommended for future experiments with stator bars. 6 figs., 1 tab.

Research Organization:
Brookhaven National Lab., Upton, NY (USA)
Sponsoring Organization:
DOE/ER
DOE Contract Number:
AC02-76CH00016
OSTI ID:
7023783
Report Number(s):
BNL-43654; ON: DE90007355
Country of Publication:
United States
Language:
English