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News & Views, Volume 49 | Hydroelectric Penstock Inspection - Field NDE Services

News & Views, Volume 49 | Hydroelectric Penstock Inspection: Field NDE Services

News & Views, Volume 49 | Hydroelectric Penstock Inspection - Field NDE ServicesBy:  Jason Van Velsor and Jeff Milligan

Our talented experts, using the latest technology and methods, deliver unmatched value, actionable information, and engineering knowledge for the management of your most critical assets.

Many of the penstocks used in the hydroelectric power industry have been in service for over 50 years.  Often with older components, historical documents like, as-built drawings and proof of material composition no longer exist.  This information is critical for inspection, repair and replacement decisions.  SI has the expertise to assist hydro clients with everything from material verification, inspection, and fitness-for-service analysis to keep penstock assets in-service for many more years to come.

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News & View, Volume 46 | Application of Probabilistic Flaw Tolerance Evaluation Optimizing NDE Inspection Requirements

News & Views, Volume 46 | Application of Probabilistic Flaw Tolerance Evaluation Optimizing NDE Inspection Requirements

By:  Christopher Lohse

News & View, Volume 46 | Application of Probabilistic Flaw Tolerance Evaluation Optimizing NDE Inspection RequirementsThere have been several industry initiatives to support optimization of examination requirements for various items/components (both Class 1 and Class 2 components) in lieu of the requirements in the ASME Code, Section XI.  The ultimate objective of these initiatives is to optimize the examination requirements (through examination frequency reduction, examination scope reduction, or both) while maintaining safe and reliable plant operation.  There are various examples of examination optimization for both boiling water reactors (BWRs) and pressurized water reactors (PWRs).  Each of these technical bases for examination optimization relies on a combination of items.  The prior technical bases have relied on: (1) operating experience and prior examination results as well as (2) some form of deterministic and/or probabilistic fracture mechanics.   For BWRs, the two main technical bases that are used are BWRVIP-05 and BWRVIP-108.  These technical bases provide the justification for scope reduction for RPV circumferential welds, nozzle-to-shell welds, and nozzle inner radius sections.  For PWRs, the main technical basis for RPV welds is WCAP-16168.  These technical bases are for the RPV welds of BWRs and PWRs which represent just a small subset of the examinations required by the ASME Code, Section XI.  Therefore, the industry is evaluating whether technical bases can be optimized for other components requiring examinations. 

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News & View, Volume 46 | The Newest Phased Array Ultrasonic Technique- Full Matrix Capture

News & Views, Volume 46 | The Newest Phased Array Ultrasonic Technique: Full Matrix Capture

By: Jeff Milligan, Steve Gressler, and Allen PorterNews & View, Volume 46 | The Newest Phased Array Ultrasonic Technique- Full Matrix Capture

Full Matrix Capture (FMC) and Total Focusing Method (TFM) have evolved over the past few years into NDE buzz words that warrant explanation and context for their proper and successful application.  Structural Integrity (SI) is well vested and engaged in FMC and actively exploring the use of this technology where it enhances ultrasonic sensitivity and characterization to bring added value to our clients.  An explanation of these technologies and what they mean to the future of ultrasonic inspection follows.

Phased Array Ultrasonic Testing (PAUT) has evolved significantly over the last 20+ years, with improvements and innovations in sensor design, signal processing, and data interpretation; however, the method by which PAUT is applied has remained relatively unchanged: Excite an array of transducer elements with predetermined time delays, called focal laws, and receive resulting reflections with the array of transducer elements,

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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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