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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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.”
Alexander Agung, Danny Lathouwers, Tim H. J. J. van der Hagen, Hugo van Dam, Christopher C. Pain
Nuclear Technology | Volume 165 | Number 2 | February 2009 | Pages 133-144
Technical Paper | Fission Reactors | doi.org/10.13182/NT09-A4081
Articles are hosted by Taylor and Francis Online.
A new design of a fluidized bed has been proposed and it has been shown that under steady condition the reactor is able to produce power up to 120 MW. To study the behavior of the reactor under transient conditions as well as its stability, a model describing the coupling of neutronics, thermal hydraulics, and fluidization is applied. The objective of this study is to comprehend whether the reactor is stable under its operational range. Further, knowledge of the extent of operational parameters under large perturbations is necessary for a safe operation.The stability of the system is investigated by numerical means and is performed by linearizing and perturbing the system around its equilibrium points to form Jacobian matrices. The resulting matrices are further used to obtain the eigenvalues of the system. The system is investigated under variation of mass flow rate, and it is found that within the operational range the eigenvalues are located in the negative part of the phase plane, implying linear stability. Further, the calculated decay ratios indicate a strongly damped system.Simulations of transient conditions are performed, namely, a step change in coolant flow rate and inlet temperature, representing situations that might occur in real operations of the reactor. The coolant flow rate is varied by ±1 kg/s and the inlet gas temperature is varied by ±10 K from their steady state of 33 kg/s and 543 K, respectively. Another transient is also simulated, i.e., a transient related to noise resulting from stochastic movements of the fuel particles. For this purpose, an additional term is included in the reactivity feedback and modeled as a time-dependent external reactivity. Magnitude of the variance for this simulation is obtained from the preceding static calculations. These simulations show that the total power of the reactor may fluctuate and reach high values. However, the fuel temperature, thanks to passive reactivity feedback, is well below safety limits at all times.