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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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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Report: New York state adding 1 GW of nuclear to fleet
New York Gov. Kathy Hochul has instructed the state’s public electric utility to add at least 1 gigawatt of new nuclear by building a large-scale nuclear plant or a collection of smaller modular reactors, according to the Wall Street Journal.
Joseph J. Cambareri (NCSU), Jun Fang (ANL), Andre Gouws, Igor A. Bolotnov (NCSU)
Proceedings | 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) | Charlotte, NC, April 8-11, 2018 | Pages 335-340
Understanding the dynamics behind bubbly flows is critical to the analysis of a pressurized water reactor (PWR) system, but there are still phenomena within bubbly flows that are not fully understood. Utilizing direct numerical simulations (DNS) coupled with interface tracking methods (ITM), high-fidelity numerical data can be extracted from bubbly flow simulations for use in the development of closure laws and mechanistic models. With the use of a bubble tracking algorithm that can record information specific to individual bubbles within the flow, numerical data can be gathered on a fundamental level. State-of-the-art high performance computing (HPC) facilities were used to simulate two-phase, turbulent flow within the subchannel of a PWR for both a simple subchannel geometry and one with a spacer grid and mixing vanes included. A statistical analysis of the numerical data gathered from these simulations can then be studied to discover the dependency of bubble dynamics upon flow conditions. Bubbles can be split into groups in relation to their distance to the wall, and the dependency of quantities such as the relative velocity or the drag coefficient upon the distance to the wall can be investigated. This work splits previously generated numerical data into seven bubble groups for further statistical analysis, as well as dividing the subchannel into “quadrants” to check for time averaged imbalances in bubble population resulting from geometric influences. These post processing techniques seek to offer insight into the physics behind bubbly flow conditions.