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Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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.”
Lothar Wolf, Helmut Holzbauer, Manfred Schall
Nuclear Technology | Volume 125 | Number 2 | February 1999 | Pages 155-165
Technical Paper | Reactor Safety | doi.org/10.13182/NT99-A2939
Articles are hosted by Taylor and Francis Online.
Advanced nuclear reactor concepts heavily rely on the availability and efficiency of passive cooling systems. This especially holds for advanced containment designs with passive decay heat removal systems that function by natural phenomena. Also, the development of catalyst modules for hydrogen mitigation measures is based on natural basic principles leading to hydrogen reduction and additional atmospheric mixing.To prove the functionability and availability of passive systems and their respective components, demonstration experiments at different scales are mandatory. In addition, it is the general perception that many more improved computational tools are needed for this purpose, where present lumped-parameter analysis methods are insufficient to provide the necessary information about local details and spatial distributions. Therefore, the next step in the development of analytical/numerical models is the transition/extension from lumped-parameter to multidimensional models and containment analysis codes.Also, recent posttest lumped-parameter analyses of the Heiss Dampf Reaktor H2 distribution experiment E11.2 with preexisting atmospheric stratification show a number of deficiencies compared with the data, indicating a need for more detailed modeling.The GOTHIC thermal-hydraulic containment code provides this required extension of the lumped-parameter model by incorporating multidimensional submodels for selected nodes (subcompartments). Applications of both model types to simulate hydrogen dispersion experiments in the Battelle Model Containment (BMC) demonstrate the limitations of the traditional approach and the improvement achieved by the multidimensional simulation. The importance of thermal and hydrogen concentration stratifications, the interactions with structural heat conductors, and the requirements to set up a consistent model when coupling lumped-parameter and multidimensional representations are discussed.Several hydrogen-mixing experiments performed in the BMC more than a decade ago were simulated with multidimensional GOTHIC models.Three types of modeling concepts have been tested:1. lumped-parameter model2. each compartment modeled two-dimensionally with the intercompartment connections simulated as flow path junctions3. full three-dimensional nodalization of the BMC, intercompartment connections simulated as gaps.The results of these GOTHIC calculations are compared with the experimental data and demonstrate the improvements that can be achieved by performing multidimensional containment simulations.