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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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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A webinar, and a new opportunity to take ANS’s CNP Exam
Applications are now open for the fall 2025 testing period for the American Nuclear Society’s Certified Nuclear Professional (CNP) exam. Applications are being accepted through October 14, and only three testing sessions are offered per year, so it is important to apply soon. The test will be administered from November 12 through December 16. To check eligibility and schedule your exam, click here.
In addition, taking place tomorrow (September 19) from 12:00 noon to 1:00 p.m. (CDT), ANS will host a new webinar, “How to Become a Certified Nuclear Professional.” More information is available below in this article.
Hiral Kadakia, Andrew Baker, Mark Paulsen
Nuclear Technology | Volume 202 | Number 1 | April 2018 | Pages 71-80
Technical Paper | doi.org/10.1080/00295450.2017.1419785
Articles are hosted by Taylor and Francis Online.
RETRAN-3D is a versatile and reliable best-estimate five-equation thermal-hydraulic analysis code used for anticipated operational occurrences and for small-break loss-of-coolant accidents transient analysis of light water reactor systems. The RETRAN-3D accumulator model has been revised to predict behavior during short-intermediate and long-term transients in pressurized water reactors. The accumulator is a single-volume, two-region nonequilibrium component model that includes vessel geometry, wall metal mass, and wall and liquid region surface areas as a function of level. The model accounts for heat transfer effects from the vessel wall to the vapor region using a lumped parameter model and accounts for heat transfer from the liquid region to the gas region. Mass and energy balance equations are solved for the liquid region, and an energy equation is solved for the vapor region. A pressure equation of state provides the pressure as a function of the mass and energy of the liquid and vapor regions.
The new model is validated with loss-of-fluid test and semiscale experimental data, demonstrating that the model is capable of predicting the behavior of an accumulator for transients ranging from short term to long term and accounts for the effects of accumulator geometry such as surface area-to-volume ratio.