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Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
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2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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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
NRC reviewing 2 unplanned shutdowns at South Texas Project
The U.S. Nuclear Regulatory Commission began a special inspection last week at South Texas Project nuclear power plant into two incidents at the site, which led to separate, unplanned shutdowns of both Units 1 and 2.
X. Zhao (MIT), A. Wysocki, R. Salko (ORNL), K. Shirvan (MIT)
Proceedings | 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) | Charlotte, NC, April 8-11, 2018 | Pages 148-155
The critical heat flux (CHF) corresponding to the departure from nucleate boiling (DNB) is one of the major limiting factors in the design and operation of pressurized water reactors (PWRs). Various predictive tools have been proposed for steady-state conditions. Empirical correlations and look-up tables yield relatively good agreement with specific experimental datasets and are widely used in subchannel codes for PWR transient simulations. However, experimental studies have revealed that during fast transients the CHF values can become significantly higher than those in steady-state or slow transient scenarios, causing this modeling approach to result in overly conservative DNB prediction. This paper presents a mechanistic transient CHF model. Based on prior work, two DNB triggering mechanisms prevail in this model - the hydrodynamic thinning process and the thermal thinning process - both of which rely on the liquid sublayer dryout theory. Both mechanisms evaluate the depletion of the liquid sublayer underneath vapor slugs flowing over the channel. This model is further validated against three sets of power transient experiments at different operating conditions. While it clearly outperforms steady-state approaches and generally agrees closely with measurements, it still remarkably under-estimates CHF for very fast transients at low pressure. Future investigations will address this limitation.