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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.”
Dale B. Lancaster, Emilio Fuentes, Chi H. Kang, Meraj Rahimi
Nuclear Technology | Volume 125 | Number 3 | March 1999 | Pages 255-270
Technical Paper | Fission Reactors | doi.org/10.13182/NT99-A2946
Articles are hosted by Taylor and Francis Online.
A conservative methodology is presented that would allow taking credit for burnup in the criticality safety analysis of spent nuclear fuel (SNF) packages. The method is based on the assumption that the isotopic concentration in the SNF and cross sections of each isotope for which credit is taken must be supported by validation experiments. The method allows credit for the changes in the 234U, 235U, 236U, 238U, 238Pu, 239Pu, 240Pu, 241Pu, 242Pu, and 241Am concentration with burnup. No credit for fission product neutron absorbers is taken. The methodology consists of five major steps:1. Validate a computer code system to calculate isotopic concentrations of SNF created during burnup in the reactor core and subsequent decay. Chemical assay benchmarks are used for this purpose, in conjunction with a method for assessing the calculational bias and uncertainty for each isotope.2. Validate a computer code system to predict the subcritical multiplication factor keff of an SNF package by use of UO2 and UO2/PuO2 critical experiments. The method uses an upper safety limit on keff (which can be a function of trending parameters) to ensure that the calculated keff when increased for the bias and uncertainty is <0.95.3. Establish conditions for the SNF (depletion analysis) and package (criticality analysis) that bound keff. Bounding axial and horizontal profiles must be established to ensure that the "end effect" and "horizontal effect" are accounted for conservatively.4. Use the validated codes and bounding conditions to generate package-loading criteria (burnup credit loading curves). Burnup credit loading curves show the minimum burnup required for a given initial enrichment.5. Verify by measurement that SNF assemblies meet the package-loading criteria, and confirm proper assembly selection prior to loading.