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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 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. 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.”
Alan H. Wells, Albert J. Machiels
Nuclear Technology | Volume 179 | Number 2 | August 2012 | Pages 180-188
Technical Paper | Reactor Safety | doi.org/10.13182/NT12-A14090
Articles are hosted by Taylor and Francis Online.
Spent nuclear fuel transported in large casks must remain subcritical in all credible configurations for normal operation and hypothetical accident conditions. The effects on spent nuclear fuel reactivity from "worst-case" accident scenarios were surveyed in NUREG/CR-6835, "Effects of Fuel Failure on Criticality Safety and Radiation Dose for Spent Fuel Casks." The survey used scenarios that were postulated to provide theoretical upper limits for reactivity effects of fuel relocation, although they were described as going "beyond credible conditions." These scenarios involved physical changes either to fuel assembly rod arrays or to collections of fuel pellets with the fuel skeleton removed. To provide more credible estimates of the probability and maximum reactivity changes, a process is presented that deconstructs each scenario into a set of subscenarios and identifies the physical phenomena required to create the subscenario. The boundary between credible but unlikely scenarios and incredible scenarios is more easily discernible with this process.For marginally credible worst-case scenarios, it is concluded that the maximum reasonable reactivity increase either is less than the mandated administrative nuclear criticality safety margin for scenarios involving physical changes to fuel assembly rod arrays or is a substantial reactivity decrease for scenarios involving collections of fuel pellets. A cask designer could apply scenario deconstruction to evaluate the physical limits that apply to a particular transportation cask, and perform calculations specific to a particular cask design to show that criticality safety requirements are met.