ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
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.
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!
Latest Magazine Issues
Jul 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
August 2024
Nuclear Technology
Fusion Science and Technology
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.”
Shirley Dickinson, Howard E. Sims
Nuclear Technology | Volume 129 | Number 3 | March 2000 | Pages 374-386
Technical Paper | Reactor Operations and Control | doi.org/10.13182/NT00-A3068
Articles are hosted by Taylor and Francis Online.
The prediction of iodine behavior in the containment of a pressurized water reactor following a loss-of-coolant accident requires a reliable model of the chemistry of iodine in aqueous solution. The INSPECT model, which has been developed over several years, contains a large number of the relevant chemical reactions of iodine and water radiation chemistry. Since the reaction set was first assembled, new data on rate constants and mechanisms have become available. In addition, the application of the model to various small-scale experiments has revealed problems in the modeling of some reactions, leading to an underprediction of the iodine volatility at high pH, although the experiments have demonstrated that the high-pH volatility remains satisfactorily low.The INSPECT model is described along with the recent modifications that have been made to take account of new data and to improve the modeling where appropriate. The most important of these were (a) changes to the H2O2 - I2 reaction mechanism, (b) the inclusion of an impurity-catalyzed first-order O2- disproportionation reaction, and (c) the treatment of atomic I as a volatile species. These modifications have led to an increase in the predicted iodine volatility under neutral and alkaline conditions. At pH 4.6, where the original model had been found to be satisfactory, the modifications did not result in a significant change in the predicted volatility.The predictions of the revised model are compared with the results of a comprehensive series of experiments, which are described in a separate paper. The model predictions are in generally good agreement with the experiments for the range of conditions studied (pH 4.6 to 9, 10-5 to 10-4 mol/dm3 I-, 0.02 to 0.2 Mrad/h, 25 to 70°C). The results at neutral and high pH show a significant improvement over the previous version of the model, which underestimated the volatility at pH 9 by more than two orders of magnitude.