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Division Spotlight
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
Prasad Vegendla, Rui Hu, Aleksandr Obabko, Haomin Yuan (ANL), Richard Schultz (Idaho State Univ), Yassin Hassan (Texas A&M)
Proceedings | Advances in Thermal Hydraulics 2018 | Orlando, FL, November 11-15, 2018 | Pages 1169-1180
In High Temperature Gas Reactors (HTGR), gas flow patterns are very complex and reduced models (1D or 2D) may be too simplified to predict accurate reactor performance. 3D Computational Fluid Dynamics (CFD) models can help provide the detailed information needed to optimize the reactor thermal performance. The main objective of this work is to verify and validate the CFD models with data for a 1/16th scaled Very High Temperature Reactor (VHTR) measured at Texas A&M University. The upper plenum is one of the main components in a VHTR where the hot and cold fluids mix with each other to determine the fluid temperature.
In this paper, jet flow characteristics are investigated in two different upper plenum configurations; (i) single coolant channel and (ii) multiple (five) coolant channel. First, CFD models are verified with two different codes, Nek5000 and STAR-CCM+, for the single coolant channel configuration. The predicted jet velocities are identical in both codes with a marginal deviation due to differences in turbulence modeling. Second, the STAR-CCM+ Reynolds Stress Model (RSM) is validated with a multiple coolant channel configuration. Good agreement between simulated results and measured data is obtained for jet peak velocities. Also, the predicted flow asymmetry is similar to experimental data. In contrast, significant deviations are observed in the off side peak velocities due to the assumption of a constant inlet mass flow rate.