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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Deep geologic repository progress—2025 Update
Editor's note: This article has was originally published in November 2023. It has been updated with new information as of June 2025.
Outside my office, there is a display case filled with rock samples from all over the world. It contains a disk of translucent, orange salt from the Waste Isolation Pilot Plant near Carlsbad, N.M.; a core of white-and-bronze gneiss from the site of the future deep geologic repository in Eurajoki, Finland; several angular chunks of fine-grained, gray claystone from the underground research laboratory at Bure, France; and a piece of coarse-grained granite from the underground research tunnel in Daejeon, South Korea.
T. Höhne, E. Krepper, D. Lucas, G. Montoya
Nuclear Technology | Volume 205 | Number 1 | January-February 2019 | Pages 48-56
Technical Paper | doi.org/10.1080/00295450.2018.1495025
Articles are hosted by Taylor and Francis Online.
The paper presents the extension of the GENeralized TwO Phase flow (GENTOP) model for phase transfer and discusses the submodels used. Boiling flow inside a wall heated vertical pipe is simulated by a multifield computational fluid dynamics (CFD) approach. Subcooled water enters the pipe from the lower end and heats up first in the near-wall region leading to the generation of small bubbles. Farther along the pipe, larger and larger bubbles are generated by coalescence and evaporation. This leads to transitions of the two-phase-flow patterns from bubbly to churn-turbulent and annular flow. The CFD simulation is based on the recently developed GENTOP concept. It is a multifield model using the Euler-Euler approach. It allows the consideration of different local flow morphologies including transitions between them. Small steam bubbles are handled as dispersed phases while the interface of large gas structures is statistically resolved. The GENTOP submodels and the wall boiling model need a constant improvement and separate, intensive validation effort using CFD-grade experiments.