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High Energy Piping Assessment

High Energy Piping (HEP) System Assessments involves the inspection and the evaluation of the piping, pipe supports, and welds of selected operating systems within the plant. The affected plant systems are systems that operate at high temperatures and / or high pressures.

There are a number of damage mechanisms that fall under a HEP Assessment – Fatigue, Creep, External Corrosion (Corrosion under Insulation - CUI), and Flow Accelerated Corrosion (FAC). The plant piping systems that generally fall under a HEP Assessment are:

  • Main Steam System
  • Hot Reheat System
  • Cold Reheat System
  • Auxiliary Steam System
  • Boiler Blowdown System
  • Boiler Feed System
  • Heater Drain System
  • Heater Vent System

Flow Accelerated Corrosion (FAC) is the dissolution of the normally protective oxide layer on the inside surface of carbon and low alloy steel piping.  The iron oxides that naturally form on the exposed surface of the pipe are removed by mass transfer to the de-oxygenated water flowing over the pipe inside surface at elevated temperatures.  This results in thinning of the pipe wall, which in turn can lead to leaks and potential catastrophic ruptures that adversely impact both personnel safety and plant reliability.

FAC is influenced by the flow rate, pH, oxygen content, temperature and geometry of the piping system.  There is a significant temperature and oxygen sensitivity. FAC is most severe at approximately 300oF—far below where many fossil plant piping programs investigate piping integrity.  This phenomenon can also cause degradation of other plant equipment such as heater shells, tanks, and other vessels.

Corrosion Under Insulation (CUI) is a serious concern where insulated piping, equipment, tanks, and vessels are exposed to conditions where water travels into the space between the metal surface of the component and the insulation.  This can occur on carbon steel, low alloy, and stainless steel materials.


Altran’s Commitment

Highly publicized accidents and other less well-known incidents have attracted the attention of utilities, and industry groups such as EPRI.  The utilities concerns have been in personnel safety, equipment loss, and plant downtime.

Altran offers a comprehensive approach to assist the utilities with HEP Assessments.  Altran’s HEP Assessments draw on our number of years of utility experience, our knowledgeable engineering design staff, and our evaluation methodology which includes the latest industry trends.  Within the framework of this approach, we offer the following services:


Altran High Energy Piping Services

  • High Energy Piping Pipe Support Inspectionss
  • Evaluation of Rigid and Variable Spring Supports
  • Structural Evaluation of Piping Systems
  • Material Testing Laboratory
  • UT Inspections
  • Inspection and Assessment of Welds, i.e. Dissimilar Welds, Welded Attachments, etc.
  • Hardness Testing of Welds and Base Metal
  • Spot Materials Verification Using X-Ray Fluoroscopy (XRF)
  • Attemperator / Desuperheater Inspections., i.e. Hot Reheat, Auxiliary Steam, Superheater, Reheat Desuperheater
  • Flow Acceleration Corrosion (FAC) Program
  • Corrosion Under Insulation (CUI) Program
Altran is the industry leader in the field of Flow Accelerated Corrosion and has performed program development/enhancement, outage support, and independent reviews for over 150 different nuclear and fossil units. Aaron Kelley, Director of Engineering Programs

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