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Conference Spotlight
2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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Japan gets new U for enrichment as global power and fuel plans grow
President Trump is in Japan today, with a visit with new Prime Minister Sanae Takaichi on the agenda. Takaichi, who took office just last week as Japan’s first female prime minister, has already spoken in favor of nuclear energy and of accelerating the restart of Japan’s long-shuttered power reactors, as Reuters and others have reported. Much of the uranium to power those reactors will be enriched at Japan’s lone enrichment facility—part of Japan Nuclear Fuel Ltd.’s Rokkasho fuel complex—which accepted its first delivery of fresh uranium hexafluoride (UF₆) in 11 years earlier this month.
Dong Hun Lee, Dong-Ha Lee, Jae Jun Jeong, Kyung Doo Kim
Nuclear Technology | Volume 198 | Number 1 | April 2017 | Pages 79-84
Technical Note | doi.org/10.1080/00295450.2017.1287503
Articles are hosted by Taylor and Francis Online.
Frictional pressure drop (also called wall drag) for a two-phase flow has been investigated for several decades. However, the two-phase frictional pressure drop models in the state-of-the-art thermal-hydraulic system codes are significantly different from each other, especially in the way to partition the wall friction force of liquid and vapor phases in the two-fluid momentum equations. This may lead to unphysical results in some flow conditions.
In this technical note, the two-phase wall frictional pressure drop models in the RELAP5/MOD3, TRACE V5, and SPACE codes are discussed in terms of the wall friction partition into the liquid and vapor momentum equations. To show the effect of different partition methods in the three codes, we simulated air-water bubbly flows in a horizontal pipe. The results of the calculations show that the partition method has a direct effect on the relative velocity of the two phases, and it may lead to unphysical behaviors of dispersed bubbles and droplets. It is strongly recommended to revisit the two-fluid formulation and the partition method of two-phase wall drag in the state-of-the-art system codes.