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Division Spotlight
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
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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August 2024
Nuclear Technology
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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.”
Chi H. Kang, Dale B. Lancaster
Nuclear Technology | Volume 125 | Number 3 | March 1999 | Pages 292-304
Technical Paper | Fission Reactors | doi.org/10.13182/NT99-A2948
Articles are hosted by Taylor and Francis Online.
A flat, uniform axial burnup assumption, preferred for its computational simplicity, does not always conservatively estimate the pressurized water reactor spent-fuel-cask multiplication factors. Rather, the reactivity effect of the significantly underburned fuel ends, usually referred to as the "end effect," can be properly treated by explicit modeling of the axial burnup distribution based on limiting axial burnup profiles. An alternative approach to this laborious explicit modeling is to augment the multiplication factor determined from an axially uniform calculation by an appropriate keff bias. Based on the observation that the end effect increases with a decrease in the cask size, conservative keff bias curves are determined by applying the limiting axial burnup profiles and assuming a single-assembly cask configuration. However, because of their conservative nature, the keff bias curves are not recommended unless there is a large reactivity margin in the particular cask of interest.The horizontal burnup distribution poses less reactivity concern simply because the limiting arrangement in a cask is an unlikely event. The possibility of two or more assemblies with low burnup zones placed inward and next to each other is small, while the underburned fuel ends will surely be next to each other. Regardless, the reactivity effect of the horizontal burnup distribution is bounded by assuming a conservative horizontal burnup gradient within individual assemblies and the most reactive arrangement of multiple assemblies in spent nuclear fuel casks. This approach can have a significant effect on small cask designs where the orientation of fuel assemblies has a substantial influence on the calculated multiplication factor because of the large radial neutron leakage.