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Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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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Dragonfly, a Pu-fueled drone heading to Titan, gets key NASA approval
Curiosity landed on Mars sporting a radioisotope thermoelectric generator (RTG) in 2012, and a second NASA rover, Perseverance, landed in 2021. Both are still rolling across the red planet in the name of science. Another exploratory craft with a similar plutonium-238–fueled RTG but a very different mission—to fly between multiple test sites on Titan, Saturn’s largest moon—recently got one step closer to deployment.
On April 25, NASA and the Johns Hopkins University Applied Physics Laboratory (APL) announced that the Dragonfly mission to Saturn’s icy moon passed its critical design review. “Passing this mission milestone means that Dragonfly’s mission design, fabrication, integration, and test plans are all approved, and the mission can now turn its attention to the construction of the spacecraft itself,” according to NASA.
Brian L. Mount, Martin Lopez de Bertodano
Nuclear Technology | Volume 171 | Number 2 | August 2010 | Pages 161-170
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT10-A10781
Articles are hosted by Taylor and Francis Online.
This work is a three-dimensional (3-D) implementation of the computational fluid dynamics (CFD) model for a shutdown boron injection jet of a pressurized heavy water reactor, previously developed for the axisymmetric case. The boron shutdown system injects round boron jets into a moderator tank with an array of cylindrical coolant channels. The boron injection jets are tilted with respect to the coolant channels. The 3-D formulation allows the calculation of the curved trajectory of a jet that is deflected by the coolant channels. Furthermore, the modeling of the turbulent jet mixing is performed with a realizable k- model to obtain the concentration of boron around the jet axis. The final objective is to predict the distribution of boron inside the moderator tank to calculate the insertion of negative reactivity into the reactor during a fast shutdown with a multidimensional PARCS/RELAP5 coupled model. The implementation of the present CFD results into PARCS/RELAP5 and the neutronic results are discussed in a separate paper.A porous-medium approach is used to represent the coolant channels. This porous-medium methodology is based on a volume average of the governing equations that is equivalent to the two-fluid model used for two-phase flows. The additional source terms that appear because of the averaging (i.e., constitutive relations) in the present model are related to drag over an array of cylinders (i.e., the fuel channels) for the momentum equation and additional mixing source terms due to the cylinders for both the turbulent kinetic energy and the turbulent dissipation transport equations.The CFD model is validated with experimental data of the boron concentration distribution obtained in a 1:7.66 scale facility representing the jets and the moderator tank. Good agreement is achieved for the trajectory of the jet centerline. The transverse spreading of the boron due to turbulence is also well predicted, though the CFD results somewhat overpredict the peak concentration compared with the measurements.
