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Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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.”
Raymond K. Maynard, Tushar K. Ghosh, Robert V. Tompson, Dabir S. Viswanath, Sudarshan K. Loyalka
Nuclear Technology | Volume 172 | Number 1 | October 2010 | Pages 88-100
Technical Paper | Materials for Nuclear Systems | doi.org/10.13182/NT10-6
Articles are hosted by Taylor and Francis Online.
An experimental system was constructed in accordance with the standard ASTM C835-06 to measure the total hemispherical emittance (emissivity) of structural materials of interest in very high temperature reactor (VHTR) systems. First, data were acquired for 304 stainless steel as well as for oxidized and unoxidized nickel, and good reproducibility and agreement with the literature was found. Emissivity of Hastelloy X was then measured under different conditions that included (a) "as received" (original sample) from the supplier, (b) with increased surface roughness, (c) oxidized, and (d) graphite coated. Measurements were made over a wide range of temperatures. Hastelloy X, as received from the supplier, was cleaned before additional roughening of the surface and coating with graphite. The emissivity of the original samples (cleaned after received) varied from [approximately]0.18 to 0.28 in the temperature range of 473 to 1498 K. The apparent emissivity increased only slightly as the roughness of the surface increased (without corrections for the increased surface area due to the increased surface roughness). When Hastelloy X was coated with graphite or was oxidized, however, its emissivity was observed to increase substantially. With a deposited graphite layer on the Hastelloy, increases from 0.2 to 0.53 at 473 K and from 0.25 to 0.6 at 1473 K were observed - a finding that has strong favorable safety implications in terms of decay heat removal in postaccident VHTR environments. Initial oxidation of Hastelloy X surfaces was observed to notably increase the emissivity of the Hastelloy X but was not observed to progress significantly beyond the initial oxidation even with more prolonged exposure. Since there is likely to be initial surface oxidation of any Hastelloy X used in the construction of VHTRs, this represents an essentially neutral finding in terms of the safety implications in postaccident VHTR environments.