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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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!
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Latest News
Senate EPW Committee to hold Nieh nomination hearing
Nieh
The Senate Environment and Public Works Committee will hold a nomination hearing Wednesday for Ho Nieh, President Donald Trump’s nominee to serve as commission at the Nuclear Regulatory Commission.
Trump nominated Nieh on July 30 to serve as NRC commissioner the remainder of a term that will expire June 30, 2029, as Nuclear NewsWire previously reported.
Nieh has been vice president of regulatory affairs at Southern Nuclear since 2021, though since June 2024 he has been at the Institute of Nuclear Power Operations as a loaned executive.
A return to the NRC: If confirmed by the Senate, Nieh would be returning to the NRC after three previous stints totaling nearly 20 years.
Gulab Verma, Shobha Lata Sinha, Shashi Kant Verma, Tikendra Nath Verma
Nuclear Technology | Volume 211 | Number 7 | July 2025 | Pages 1363-1406
Review Article | doi.org/10.1080/00295450.2024.2410615
Articles are hosted by Taylor and Francis Online.
Pressurized water reactors (PWRs) are prevalent in nuclear power plants worldwide, contributing most of the electricity produced from nuclear energy. Modern PWRs allow subcooled flow boiling under their normal operating conditions to enhance the heat transfer rate. However, subcooled flow boiling might also suffer from critical heat flux (CHF) under accidental conditions, called departure from nucleate boiling, a major safety concern for the reactor’s design and operations. Thus, thermal-hydraulic analysis (THA) of subcooled flow boiling in PWRs is crucial in optimizing fuel assembly design to ensure efficient and safe operations. However, performing a THA in PWRs is a very complicated task because of the complexities involved in the operating conditions of the reactor, the physics of subcooled flow boiling, and subchannel geometry due to the presence of mixing vane grids (MVGs). In recent years, computational fluid dynamics (CFD) has emerged as a powerful tool for predicting subcooled flow boiling in various geometries, including PWR subchannels. The current study reviews CFD approaches for analyzing subcooled flow boiling in typical subchannels of a PWR under its prototypical operating condition or close to it. The impacts of various factors such as MVGs and their components (dimples, springs, and mixing vanes), cold walls, wall heat flux distributions, bowed rods, etc. on parameters such as lateral velocity, coolant pressure and temperature, void fraction, heat transfer coefficient, Nusselt number, wall heat flux partitions, CHF, etc. required to describe the behavior of coolant flow and heat transfer in subchannels, are presented. Finally, a summary of key conclusions and the scope for further research is presented.