The FIRST Indication of a Leak

by Sara on August 9, 2011

“The Triple 5 System was THE FIRST Indication of a Leak”

 

Unit :  B&W – 1300MW 3845psi

Location of Leak: Superheat Outlet Section

Facts: The unit is equipped with a 37 sensor AMS Leak Detection System and the plant has a Weekly Surveillance contract with Triple 5. 

Timeline:

March 3: During the Weekly Surveillance check sensor 11 trends at 90dB – a 4dB increase during the past week. 

March 17: The weekly surveillance check reveals an additional 6dB increase on sensor 11 reaching 96dB.  Also noted on 3/10 was sensor 24 reaching  90dB – a 6dB increase.

March 19: The plant calls Triple 5’s 24 Hour Hotline for assistance in analyzing sensor 11,  now trending at 101dB.  The plant reports minimal water loss.

March 24:  Triple 5 reports additional increases on sensors 11 and 24.  Sensor 18 trends at 87dB – a 4dB increase.

March 30:  Unit removed from service at noon as acoustic levels increase significantly.

Plant Follow Up: The initial leak was a tight crack in the middle of an original shop weld.  Six other tubes were washed with leaks ranging from pinholes to 1/4” diameter holes.  The leaks were located 10’ from the left side wall.  Sensor 11 was first to respond.  It is located 20’ below and 30’ in front of the leak.

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