A Client Power Station of CTRL Systems, Inc. utilizes the UL101 Ultrasound Detector for offline reheat leak detection. The Station has a number of 700 MW boilers. When a boiler unit is removed from service for any reason, a “reheat vacuum check” is performed to ensure there are no failures that must be addressed while the unit is offline.
The UL101 is able to detect if a small crack is present. It is first verified that vacuum is at or above 25” HGV. Once vacuum has been verified, a walkthrough of the reheat (18’ wide X 69’ long X 20’ in depth) is done slowly with the CTRL UL101. This walkthrough is performed in two locations as they also check other surrounding surfaces such as the Platen Inlet Pendants, Platen Intermediate Pendants, and Finishing Superheat Pendants, which also have vacuum on them as well.
In the event that a check either was not performed or a leak was missed and the unit was returned to service, the unit would be offline again likely within 24 to 48 hours for repairs as it would not be capable of running for any length of time with a leak.
The cost of the repair if leaks are not located and repaired is estimated:
- $80,000 to $90,000 in craft labor,
- 60 to 72 hours of lost generation which could be upwards of $240,000 (at only a $5 MWHr margin, a low margin in the summer or winter if the plant is running hard),
- and $90,000 of fuel cost for start-up.