News & View, Volume 43 | A Strategic Approach for Completing Engineering Critical Assessments of Oil and Gas Transmission Pipelines

News & Views, Volume 43 | A Strategic Approach for Completing Engineering Critical Assessments of Oil and Gas Transmission Pipelines

By:  Scott Riccardella and Steven Biles

Regulatory Overview
News & View, Volume 43 | A Strategic Approach for Completing Engineering Critical Assessments of Oil and Gas Transmission PipelinesIn January 2012, the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 was signed into law directing PHMSA to take steps to further assure the safety of pipeline infrastructure.  PHMSA issued the related Notice of Proposed Rulemaking (NPRM) for Safety of Gas Transmission and Gathering Pipelines on April 8, 2016.  Included in the NPRM were significant mandates regarding:

  • Verification of Pipeline Material (§192.607); and
  • Maximum Allowable Operating Pressure (MAOP) Verification or “Determination” (§192.624)

The NPRM proposes requirements for operators to verify the MAOP of a gas transmission pipeline when:

  1. The pipeline has experienced an in-service incident (as defined by §191.3) due to select causes1 in a High Consequence Area (HCA), “piggable” Moderate Consequence Area (MCA), or Class 3 or 4 location since its last successful pressure test
  2. The pipeline lacks Traceable, Verifiable, and Complete pressure test records for HCAs or Class 3 or 4 locations
  3. The pipeline MAOP was established by the grandfather clause (§192.619 (a)(3)) for HCAs, “piggable” MCAs, or Class 3 or 4 locations.

To verify the MAOP of a pipeline, the NPRM provides the following options:

  • Method 1: Pressure Test
  • Method 2: Pressure Reduction
  • Method 3: Engineering Critical Assessment (ECA)
  • Method 4: Pipe Replacement
  • Method 5: Pressure Reduction for segments with small potential impact radius (PIR) & diameter
  • Method 6: Use Alternative Technology

The ECA Approach
Per the NPRM, Method 3 (ECA) is defined as an analysis, based on fracture mechanics principles, material properties, operating history, operational environment, in-service degradation, possible failure mechanisms, initial and final defect sizes, and usage of future operating and maintenance procedures to determine maximum tolerable sizes for imperfections. 

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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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News & View, Volume 43 | LatitudeUsing Falcon to Develop RIA Pellet-Cladding Mechanical Interaction (PCMI) Failure Criteria

News & Views, Volume 43 | Using Falcon to Develop RIA Pellet-Cladding Mechanical Interaction (PCMI) Failure Criteria

By:  John Alvis

IntroductionNews & View, Volume 43 | LatitudeUsing Falcon to Develop RIA Pellet-Cladding Mechanical Interaction (PCMI) Failure Criteria
The goal to achieve higher fuel rod burnup levels has produced considerable interest in the transient response of high burnup nuclear fuel.  Several experimental programs have been initiated to generate data on the behavior of high burnup fuel under transient conditions representative of Reactivity Initiated Accidents (RIAs).  A RIA is an important postulated accident for the design of Light Water Reactors (LWRs). It is considered the bounding accident for uncontrolled reactivity insertions.

The initial results from RIA-simulation tests on fuel rod segments with burnup levels above 50 GWd/tU, namely CABRI REP Na-1 (conducted in 1993) and NSRR HBO-1 (conducted in 1994), raised concerns that the licensing criteria defined in the Standard Review Plan (NUREG-0800) may be inappropriate beyond a certain level of burnup.   Figure 1 is an example of a typical high burnup fuel cladding showing the oxidized and hydrided cladding of higher burnup fuel rods.  Figure 2 shows the typical radial crack path in oxidized and hydrided cladding, subjected to RIA simulation tests.  As a consequence of these findings, EPRI with the assistance of the Structural Integrity’s Nuclear Fuel Technology Division (formally ANATECH) and other nuclear industry members conducted an extensive review and assessment of the observed behavior of high burnup fuel under RIA conditions.  The objective was to conduct a detailed analysis of the data obtained from RIA-simulation experiments and to evaluate the applicability of the data to commercial LWR fuel behavior during a Rod Ejection Accident (REA) or Control Rod Drop Accident (CRDA).  The assessment included a review of the fuel segments used in the tests, the test procedures, in-pile instrumentation measurements, post-test examination results, and a detailed analytical evaluation of several key RIA-simulation tests.

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News & View, Volume 43 | TRU Compliance- The Standard for Seismic, Wind, and Blast Certification

News & Views, Volume 43 | TRU Compliance: The Standard for Seismic, Wind, and Blast Certification

By:  Andy Coughlin

About TRU COMPLIANCE

News & View, Volume 43 | TRU Compliance- The Standard for Seismic, Wind, and Blast CertificationAs the product certification arm of Structural Integrity, TRU Compliance stands for safety and code compliance when failure is not an option. Our clients manufacture cutting edge products that push the limits of operational performance and efficiency in many industries. We help them achieve continued performance during earthquakes, high wind events, explosions, and a host of other extreme events.

At TRU Compliance, we believe that achieving code compliance in these areas should not be complicated. So, we continually invest in the development of innovative systems and approaches to simplify the lives of our clients and deliver efficient and transparent results, every time.

TRU Compliance is a recognized leader in Seismic, Wind & Blast product certification. We are a full-service product certification agency executing project specific and product line approvals for a range of code requirements. The TRU Compliance team has been providing product certification services since 2008 and recently joined forces with Structural Integrity in May 2017, thus expanding our resources and reach.

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News & View, Volume 43 | Metallurgical Lab- Dissimilar Metal Welds (DMW) in Boiler Tubing The need for confirmation- A Case Study

News & Views, Volume 43 | Metallurgical Lab: Dissimilar Metal Welds (DMW) in Boiler Tubing

By:  Tony Studer

The need for confirmation: A Case Study

News & View, Volume 43 | Metallurgical Lab- Dissimilar Metal Welds (DMW) in Boiler Tubing The need for confirmation- A Case StudyAs plants age, the need for inspection for service related damage to ensure unit reliability increases. There are several approaches that plants can take to reduce the risk of premature failures and proactively manage their DMWs. First is metallurgical sampling. Based on temperature profiles across the boiler, operating conditions, and operating history, DMWs can be selected for laboratory analysis. This will provide some insight into possible damage accumulation; however, the better approach, if damage is suspected, is to perform an ultrasonic inspection of the DMWs. This allows inspection of all the DMWs, and only requires access and surface preparation. If indications are detected, then tube sampling should be performed. It is critical to perform a metallurgical analysis of several of the DMWs suspected of containing service damage to confirm that the indications are service related and to help establish the extent of the damage compared to ultrasonic testing results. Typical DMW damage is described in the Featured Damage Mechanism article. The importance of the metallurgical analysis is demonstrated in the three following case studies.

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News & View, Volume 43 | Metallurgical Lab Featured Damage Mechanism- Failure of Dissimilar Metal Welds (DMW) in Steam-Cooled Boiler Tubes

News & Views, Volume 43 | Metallurgical Lab Featured Damage Mechanism: Failure of Dissimilar Metal Welds (DMW) in Steam-Cooled Boiler Tubes

By:  Wendy Weiss

News & View, Volume 43 | Metallurgical Lab Featured Damage Mechanism- Failure of Dissimilar Metal Welds (DMW) in Steam-Cooled Boiler TubesLarge utility-type steam generators inevitably contain a large number of pressure part welds that join components fabricated from different alloys.

Background
The welds made between austenitic stainless steel tubing and the lower-alloyed ferritic grades of tubing (T11, T22) deserve special mention because of the early failures that developed in some of these dissimilar metal welds (DMWs) soon after their introduction in superheater and reheater assemblies.  Prior to the mid-1970s, many DMWs were fabricated either as standard fusion welds using an austenitic stainless filler metal, such as TP308, or as induction pressure welds, in which the tubes were fused directly to each other without the addition of filler metal.  Some of these welds failed after less than 40,000 hours of operation, with the earliest failures being associated with DMWs that operated “hot” in units that cycled heavily and were subjected to bending stresses during operation. 

After the mid-1970s, and in response to extensive research carried out by EPRI and other organizations, an increasing number of DMWs in superheater and reheater tubes were fabricated as fusion welds using nickel-based filler metals, such as the INCO A, INCO 82, INCO 182, etc.

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News & View, Volume 43 | Delivering the Nuclear Promise- 10 CFR 50.69 Alternative Treatments for Low Safety-Significant Components

News & Views, Volume 43 | Delivering the Nuclear Promise: 10 CFR 50.69 Alternative Treatments for Low Safety-Significant Components

By:  Terry Herrmann

News & View, Volume 43 | Delivering the Nuclear Promise- 10 CFR 50.69 Alternative Treatments for Low Safety-Significant ComponentsAs all of us who work with nuclear energy know the US nuclear industry is engaged in a multi-year effort to generate power more efficiently, economically and safely. A key goal includes a significant reduction in operating expenses. This initiative is termed “Delivering the Nuclear Promise” (DNP) and is supported by nuclear utilities, vendors such as Structural Integrity, the Nuclear Energy Institute (NEI), Institute of Nuclear Power Operations (INPO), and the Electric Power Research Institute (EPRI).

10CFR50.69’ Risk Informed Engineering Programs (RIEP) is a regulation that enhances safety and provides the potential for large cost savings. This regulation allows plant owners to place systems, structures and components (SSCs) into one of the four risk-informed safety class (RISC) categories as indicated in the graphic to the right.

Industry experience to date suggests that 75 percent of safety-related SSCs can be categorized as RISC-3, low safety-significant (LSS), based on low risk. This is important because (a) it provides a focus on safety significance and (b) RISC-3 SSCs are exempted from “special treatment” requirements imposed by 10CFR50 Appendix B and other regulatory requirements (shown in the boxes at the bottom of page).

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