HRSG Tube Leak Detection: Helium Tracer Gas Methods for Combined-Cycle Plants

Heat Recovery Steam Generators take a constant beating from thermal cycling, flow-accelerated corrosion, and vibration fatigue. A single pinhole leak in a tube bank can quietly erode efficiency for months before it grows into a forced outage. Helium tracer gas testing gives plant performance engineers a way to find that leak while the unit is still running, long before it becomes an emergency.

Why HRSG Tubes Are Especially Leak-Prone

HRSG tube banks see repeated thermal expansion and contraction across every start-stop cycle, plus condensate chemistry that can attack tube walls from the inside. Economizer and evaporator sections are common failure points, and once a leak starts, water and steam ingress into the gas path or drum can mask the actual source, making visual inspection unreliable.

How Helium Tracer Gas Testing Works on an HRSG

Helium is introduced into the suspect tube circuit or pressure boundary at a controlled concentration. Because helium molecules are small and completely inert, they migrate through even microscopic wall breaches that would go undetected by pressure decay alone. A calibrated mass spectrometer then scans the exterior of the tube bank, casing penetrations, and header welds, pinpointing the exact leak location down to the inch.

• Detects leaks far smaller than pressure or conductivity testing can catch

• Pinpoints exact leak location rather than just confirming a leak exists

• Can be performed with the unit at reduced load or during a planned hold

• Provides objective, documented data for outage planning and repair scoping

Building Leak Detection Into Your Outage Plan

The most efficient time to run a helium survey is during a planned outage window, before boilermakers start opening tube banks blind. Pinpointing leaks in advance lets your outage team scope repairs precisely, order the right replacement material, and avoid extending the outage while crews hunt for a leak the old-fashioned way.

Ready to protect your plant's performance? Contact StrongForce, Inc. at 833-735-3257 or info@StrongForceInc.com to schedule a survey with our team.