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Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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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 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.”
Martin Knight, Paul Bryce, Sheldon Hall
Nuclear Technology | Volume 183 | Number 3 | September 2013 | Pages 398-408
Technical Paper | Fission Reactors | doi.org/10.13182/NT13-A19428
Articles are hosted by Taylor and Francis Online.
This paper describes a method of analyzing pressurized water reactor UO2/mixed oxide (MOX) cores with the lattice code WIMS and the reactor code PANTHER. "Embedded supercells," run within the reactor code, are used to correct the standard methodology of using two-group smeared data from single-assembly (SA) lattice calculations. In many other codes the weakness of this standard approach has been improved for MOX by imposing a more realistic environment in the lattice code or by improving the sophistication of the reactor code. In this approach an intermediate set of calculations is introduced, leaving both lattice and reactor calculations broadly unchanged.The essence of the approach is that the whole core is broken down into a set of embedded supercells, each extending over just four quarter assemblies, with zero leakage imposed at the assembly midlines. Each supercell is solved twice, first with a detailed multigroup pin-by-pin solution and then with the standard SA approach. Correction factors are defined by comparing the two solutions, and these can be applied in whole-core calculations.The restriction that all such calculations be modeled with zero leakage means that they are independent of each other and of the core-wide flux shape. This allows parallel precalculation for the entire cycle once the loading pattern has been determined, in much the same way that SA lattice calculations can be precalculated once the range of fuel types is known.Comparisons against a whole-core pin-by-pin reference demonstrates that the embedding process does not introduce a significant error, even after burnup and refueling. Comparisons against a WIMS reference demonstrate that a pin-by-pin multigroup diffusion solution is capable of capturing the main interface effects.This therefore defines a practical approach for achieving results close to lattice code accuracy but broadly at the cost of a standard reactor calculation.