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Division Spotlight
Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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.
Yongjun Zhu, Rongzhou Jiao
Nuclear Technology | Volume 108 | Number 3 | December 1994 | Pages 361-369
Technical Paper | Enrichment and Reprocessing System | doi.org/10.13182/NT94-A35018
Articles are hosted by Taylor and Francis Online.
Mixed trialkylphosphine oxide (TRPO) (alkyl is C6-C8) was chosen as the extractant for the removal of uranium, neptunium, plutonium, and americium from highly active waste (HAW) in China. Composition and properties of the extractant and process chemistry are based on 30 vol% TRPO-kerosene as solvent. Hexa-and tetravalent actinides are highly extractable in 30 vol% TRPO extraction from acidic HAW, and trivalent americium (curium) can be extracted effectively from HAW with a nitric acid concentration of ∼1 mol/ℓ Actinides extracted can be stripped successively by 5.5 mol/ℓ HNO3, 0.6 mol/ℓ H2C2O4, and 5% Na2CO3 into americium + rare earth, neptunium + plutonium, and uranium fractions, respectively. The loading capacity of TRPO solvent is higher than that of bifunctional organophosphorus extractants, and the radiolytic stability of TRPO is higher than that of tributyl phosphate (TBP) and bis(2-ethyl hexyl)phosphoric acid. The extraction and stripping rate of TRPO is high enough to be compatible with the centrifugal contactors. Optimized process parameters of multistage countercurrent extraction and stripping and results of experimental verification are established. In both a batch experiment with simulated nuclear power plant (NPP) spent-fuel Purex HAW and a continuous experiment with real NPP spent-fuel Purex HAW, 99.9% recovery of actinides was achieved. The modification of the solvent system with TBP to fit the conditions in the chemical pretreatment of defense HAW is considered.
