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Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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.
Motoo Fumizawa, Makoto Hishida
Nuclear Technology | Volume 109 | Number 1 | January 1995 | Pages 123-131
Technical Paper | Heat Transfer and Fluid Flow | doi.org/10.13182/NT95-A35072
Articles are hosted by Taylor and Francis Online.
Air ingress by buoyancy-driven exchange flow occurs during a standpipe rupture accident in a high-temperature engineering test reactor (HTTR). The exchange flow of helium and air through annular and Round tubes is investigated. The method of mass increment is applied to measure the exchange flow rate. A test cylinder with a small tube on the top is used for the experiment. The following results were obtained: The exchange velocity is largest for the short vertical round tube as compared with the orifice and long tube. In the annular tube, the exchange-velocity or the volumetric exchange flow rate decreases with the equivalent diameter of the annular passage under 6 mm. The annular tube is effective to reduce the air ingress flow rate from the broken standpipe of the HTTR. In the inclined round tube, the inclination angle for the maximum densimetric Froude number decreases with the increase of the length-to-diameter ratio of the tube for the helium-air system. On the other hand, this angle remains almost constant for the water-brine system. Flow visualization results indicate that the exchange flows through the inclined round tubes take place smoothly and stably in the separated passage of the tube. The flow pattern in the vertical annular tube seems to be similar to that in the inclined round tube.
