Flexible Service Risk Assessment and Inspection Plan

The modern power generation market is very different to what it was ten or even five years ago.  The requirement to provide network load flexibility is falling on combined cycle plants with HRSGs, they are having to fill the supply gap between base loaded nuclear and large coal plants and the highly variable renewable energy generators.   The result of operating at lower loads means the HRSG operating conditions may be very different from what was envisaged in the design case.   Equally the increased number of startups and shutdowns presents problems for components designed for baseload.  The problems faced by plants that are cycling or operating at off-design conditions can include:

  • Water chemistry instability due to transient conditions
  • Quenching problems in superheater and reheater tubes during condensate formation
  • Attemporator and Bypass Spray problems handling increased demand
  • Economiser shock
  • High temperatures at superheaters and reheaters leading to creep failures
  • Higher heat flux in the HP Evaporator leading to increased deposit loading
  • Increased FAC risk due to increased heat at the LP Evaporator

Tetra develops inspection plans to address these and other issues using:

  • Visual Inspection of the HRSG hot gas path
  • Borescope/videoscope inspection of waterside conditions of lead high-pressure (HP) evaporator tube panels and other areas
  • Ultrasonic testing (UT) of wall thickness for selected (high-risk) tube, header, and riser components
  • Magnetic particle testing of all accessible tube-header weld connections in the HP steam and reheater tube panels
  • UT shear wave or UT phased-array inspection of Grade 91 components
  • Visual inspection of accessible HRSG waterside components
  • External walkdown and thermography

See short flyer.

About Us

Established in 1989, Tetra Engineering has more than 25 years experience providing solutions to the power industry. We specialize in solutions for HRSGs, conventional boilers & steam-cycle balance of plant.


Our Locations

Offices in: Connecticut, USA; Nice, France; Dubai, UAE.