News and Views Archives

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

October 5, 2017/in Andy Coughlin, News and Views, TRU Compliance/by Structural Integrity

By: Andy Coughlin

About TRU COMPLIANCE

As 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.

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

October 5, 2017/in Fossil Power, Materials Laboratory, News and Views, Tony Studer/by Structural Integrity

By: Tony Studer

The need for confirmation: A Case Study

As 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.

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

October 5, 2017/in Fossil Power, Materials Laboratory, News and Views, Wendy Weiss/by Structural Integrity

By: Wendy Weiss

Large 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.

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

October 5, 2017/in News and Views, Nuclear Asset Integrity, Nuclear Energy, Terry Herrmann/by Structural Integrity

By: Terry Herrmann

As 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).