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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.
Xue Zhou Jin
Fusion Science and Technology | Volume 77 | Number 5 | July 2021 | Pages 391-402
Technical Paper | doi.org/10.1080/15361055.2021.1904769
Articles are hosted by Taylor and Francis Online.
For the helium-cooled pebble bed breeding blanket concept improved in 2016 and the associated primary heat transfer system (PHTS) following EU DEMO Baseline 2015, an ex-vessel loss-of-coolant accident (LOCA) has been investigated with the assumption of a double-ended guillotine break of a main pipe in an outboard (OB) loop of the PHTS. The break leads to helium blowdown into the tokamak cooling room. A fast plasma shutdown followed by a plasma disruption is activated after the detection of the LOCA due to the design basis accident. Regarding three affected first-wall (FW) areas in one or two OB loops, three main cases are considered. If the FW temperature reaches the defined temperature limit of 1000°C, the FW is assumed to be failed such that an in-vessel LOCA results. In total five scenarios are simulated using MELCOR 1.8.6 for fusion with respect to the affected FW areas, mitigated or unmitigated plasma disruption conditions, the options of the dry or wet suppression tank, and the transport of source terms performed in the case of the beyond design basis accident without the plasma shutdown. The transient results are discussed for the time evolution of the accident sequences, pressurization in the systems, temperature behavior in volumes and structures, and tritium and dust transport behavior.