ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Aug 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
Ho Nieh nominated to the NRC
Nieh
President Trump recently nominated Ho Nieh for the role of commissioner in the Nuclear Regulatory Commission through the remainder of a term that will expire June 30, 2029.
Nieh has been the vice president of regulatory affairs at Southern Nuclear since 2021, though he is currently working as a loaned executive at the Institute of Nuclear Power Operations, where he has been for more than a year.
Nieh’s experience: Nieh started his career at the Knolls Atomic Power Laboratory, where he worked primarily as a nuclear plant engineer and contributed as a civilian instructor in the U.S. Navy’s Nuclear Power Program.
From there, he joined the NRC in 1997 as a project engineer. In more than 19 years of service at the organization, he served in a variety of key leadership roles, including division director of Reactor Projects, division director of Inspection and Regional Support, and director of the Office of Nuclear Reactor Regulation.
Lingyan Zhao, Bin Yang, Yuchun Sun
Nuclear Science and Engineering | Volume 199 | Number 9 | September 2025 | Pages 1512-1527
Research Article | doi.org/10.1080/00295639.2025.2456369
Articles are hosted by Taylor and Francis Online.
The accurate evaluation of structural integrity necessitates considering the influence of crack-tip constraints and selecting laboratory test specimens that accurately represent the actual welded structure. In this paper, a constraint parameter Dp covering in-plane constraint and out-of-plane constraint is defined based on the equivalent plastic strain gradient at the adjacent zone of the crack front. The USDFLD (user-defined field) subroutine is employed to correlate the mechanical property parameters of the continuous transition with the geometry of the dissimilar metal-welded joint (DMWJ). The submodel technique is used to study the crack-tip constraint of a typical DMWJ under complex loading conditions. The crack-tip constraints of DMWJs are quantitatively characterized. A comparison and analysis are carried out to determine the suitable test specimens for the DMWJs with various crack lengths and locations.
The results show that the cracks located at the center of the specimens are more likely to propagate than surface cracks. The interface of SA508/52Mb is the most dangerous position in DMWJs. The constraint levels of SA508/52Mb cracks match those of the center-cracked tension [CC(T)] specimens with smaller width and thickness. Overly conservative estimation results will be produced if compact tension [C(T)] and single-edge notched bend [SEN(B)] specimens with larger width and thickness are adopted to evaluate the stress corrosion cracking behavior of SA508/52Mb cracks.
The constraint levels of 52Mb/52Mw cracks match those of the CC(T) and SEN(B) specimens with smaller width and thickness. The 52Mw/316L cracks match the C(T) specimens with larger width and thickness. Nonconservative results will be produced when the CC(T) and SEN(B) specimens are adopted to evaluate 52Mw/316L cracks.
This study provides a more accurate method for the structural integrity assessment of DMWJs that can help improve the safety and reliability of critical engineering welded structures such as nuclear power plants.
