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Decommissioning & Environmental Sciences
The mission of the Decommissioning and Environmental Sciences (DES) Division is to promote the development and use of those skills and technologies associated with the use of nuclear energy and the optimal management and stewardship of the environment, sustainable development, decommissioning, remediation, reutilization, and long-term surveillance and maintenance of nuclear-related installations, and sites. The target audience for this effort is the membership of the Division, the Society, and the public at large.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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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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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.”
Kwang Won Seul, Young Seok Bang, Hho Jung Kim
Nuclear Technology | Volume 126 | Number 3 | June 1999 | Pages 265-278
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT99-A2973
Articles are hosted by Taylor and Francis Online.
The potential of the RELAP5/MOD3.2 code was assessed for a loss-of-residual-heat-removal (RHR) event during midloop operation, and the predictability of major thermal-hydraulic phenomena was evaluated for the long-term transient. The calculations were compared for two cases of experiments conducted at the Rig of Safety Assessment-IV (ROSA-IV)/Large-Scale Test Facility (LSTF) in Japan: the cold-leg-opening and the pressurizer-manway-opening cases. In addition, the real plant responses to the event were evaluated for Yong Gwang nuclear power plant Units 3 and 4 (YGN 3/4) in Korea, especially concerning the mitigation capability to remove the decay heat through the steam generators (SGs). From the LSTF simulation, it was found that the RELAP5 code was capable of simulating the plant behavior following the loss-of-RHR event under a shutdown condition. As a result, the thermal-hydraulic transport process including noncondensable gas behavior was reasonably predicted with an appropriate time step and CPU time, and the major thermal-hydraulic phenomena agreed well with the experiment. However, there were some code deficiencies such as an estimation of large system mass errors for the long transient and severe flow oscillations in the core region. These should be improved for more accurate and reliable calculation. In the YGN 3/4 simulation, the water-filled SG case delayed the coolant discharge to containment by ~2 h and the core heatup by ~1.3 h, as compared to the emptied-SG case, because of reduction of the pressurization rate that resulted from condensation on the SG U-tube wall. For the water-filled SGs, the amount of heat transfer into the secondary side was estimated at more than 60% of the total core power throughout the transient.