News & View, Volume 46 | NDE Best Practices for Generator Rotors

News & Views, Volume 46 | NDE Best Practices for Generator Rotors

By: Paul Zayicek News & View, Volume 46 | NDE Best Practices for Generator Rotors

Three factors typically drive inspection intervals of generator rotors:

  1. a timeframe recommended by the insurance carrier or OEM
  2. an engineering evaluation that supports a different inspection interval due to service operation events or existing rotor damage
  3. industry best practices

Drivers from the OEM include issues defined in service bulletins or technical information letters that pertain to the entire fleet or some subset of the population. Intervals based on engineering evaluations can be derived from an identified damage mechanism with the rotor or with a critical component. An engineering evaluation can also provide for extended inspection intervals in situations where the generator has no inherent material issues, has a clean inspection record, and sees limited operational stress such as in a base-load unit.

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News & View, Volume 45 | Latitude™ Delivers Highlights from the First Field Deployments

News & Views, Volume 45 | Latitude™ Delivers – Highlights from the First Field Deployments

By:  Jason Van Velsor, Dave Anthony, Joe Agnew, and Michael Lashley

News & View, Volume 45 | Latitude™ Delivers Highlights from the First Field Deployments

Introduction
For the past 2 ½ years, Structural Integrity Associates (SI) has been working diligently to develop, qualify and deliver the nuclear industry’s first-of-a-kind manually acquired encoded phased array UT (PAUT) examination for Section XI dissimilar metal welds (DMWs).  Development of the encoding technology behind this effort, the LATITUDETM non-mechanized encoding system, was completed in 2017, with our application-specific inspection procedure completed and qualified through the industry’s Performance Demonstration Program (PDI) in the Spring of 2018. Now, with much enthusiasm, we are proud to report that we have successfully completed the first field deployments of the LATITUDE technology and DMW procedure during the Fall 2018 outage season.

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News & View, Volume 44 | A First-of-a-Kind NDE Innovation from SI The first PDI qualified manually-encoded DM Weld Procedure

News & Views, Volume 44 | A First-of-a-Kind NDE Innovation from SI – The first PDI qualified manually-encoded DM weld procedure

By:  Jason Van Velsor, Joe Agnew, and Owen Malinowski

News & View, Volume 44 | A First-of-a-Kind NDE Innovation from SI The first PDI qualified manually-encoded DM Weld ProcedureDetermining a course of action once in-service damage is discovered often requires applying a multi-disciplinary approach that utilizes Nondestructive Examination (NDE), analytical techniques such as stress analysis, and metallurgical lab examination.  Such was the case recently for a combined cycle plant where indications were found through NDE on the inlet sides of two identical main steam stop/control valves but were not seen on the outlet side.  In this case, Structural Integrity (SI) did not perform the field NDE but was requested to perform analytical and metallurgical assessments of the welds.  The welds in question joined the 1Cr-1Mo-1/2V (SA-356 Grade 9) main stop/control valve body castings to Grade 91 piping, so the welds represent a ferritic-to-ferritic dissimilar metal weld (DMW).  See the Dissimilar Metal Welds in Grade 91 Steel, (page 15) for further information. The welds were made using a 1Cr-1/2Mo (AWS type B2) filler metal, which matches the chromium content of the valve body, but is significantly undermatching in strength to both the valve body material and the Grade 91 piping. 

The course of action taken was to perform local stress analysis and remaining life estimates for the downstream (outlet) connections of the valves to assess likelihood of future damage and establish an appropriate re-inspection interval.  Detailed metallurgical analysis was also performed on a ring (entire circumference) section removed from one of the upstream welds (which exhibited both surface and volumetric indications in the weld metal) in order to provide insight into the damage mechanism and inform the stress analysis and remaining life estimates.

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News & View, Volume 43 | In-Line Inspection An Improvement Over Pressure Testing for Pipeline Integrity Management

News & Views, Volume 43 | In-Line Inspection – An Improvement Over Pressure Testing for Pipeline Integrity Management

By:  Scott Riccardella, Dilip Dedhia, and Peter Riccardella 

News & View, Volume 43 | In-Line Inspection An Improvement Over Pressure Testing for Pipeline Integrity ManagementStructural Integrity recently performed probabilistic fracture mechanics (PFM) analysis of a gas transmission pipeline for a major U.S. operator.  The analysis yielded interesting insights in several areas:

Pressure Testing versus In-Line Inspection
Pressure testing has long been considered the gold standard for assuring pipeline integrity.  By testing at a factor (e.g., 1.25x or 1.5x) above the Maximum Allowable Operating Pressure (MAOP), any size critical flaws in the line would fail at this pressure level and are thus removed prior to future service.  Subcritical flaws that remain after the test will be smaller than the critical flaw sizes during operation, and thus can be assumed to have some margin for growth before they become critical in service.  Flaw growth rates can be calculated based on operational and environmental factors to establish a reassessment interval for future testing or inspections.

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News & View, Volume 43 | LATITUDE™ Innovating the NDE Data Acquisition Process

News & Views, Volume 43 | LATITUDE™ Innovating the NDE Data Acquisition Process

By:  Jason Van Velsor

From the creation of the first simple stone tools to the invention of the world wide web, technological innovation has been the undercurrent that has carried the human species from our primitive survivalist ways to our present-day complexity of modern conveniences. We innovate from necessity, competition, or from a desire for an improved quality of life. Innovation has been and remains key to our survival and proliferation.

News & View, Volume 43 | LATITUDE™ Innovating the NDE Data Acquisition ProcessIn business, it is no different and innovation has been a mainstay at Structural Integrity and part of our core values since our inception in 1983. We are constantly developing and applying innovative practices and technologies to meet our clients’ toughest challenges and to provide best-in-value solutions. In this spirit, we are excited to announce one of our most recent innovations, LATITUDETM.

LATITUDE is a non-mechanized position and orientation encoding technology designed for use with nondestructive evaluation (NDE) equipment. Simply stated, LATITUDE enables an operator to manipulate a probe by hand while maintaining a digital record of the position and orientation of the probe at all times. For many applications, LATITUDE can be thought of as a fast and compact alternative to cumbersome and complicated automated inspection equipment.

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