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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.
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2024 ANS Annual Conference
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Las Vegas, NV|Mandalay Bay Resort and Casino
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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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Commercial nuclear innovation "new space" age
In early 2006, a start-up company launched a small rocket from a tiny island in the Pacific. It exploded, showering the island with debris. A year later, a second launch attempt sent a rocket to space but failed to make orbit, burning up in the atmosphere. Another year brought a third attempt—and a third failure. The following month, in September 2008, the company used the last of its funds to launch a fourth rocket. It reached orbit, making history as the first privately funded liquid-fueled rocket to do so.
Staffan Qvist
Nuclear Technology | Volume 190 | Number 1 | April 2015 | Pages 11-27
Technical Paper | Fission Reactors | doi.org/10.13182/NT14-30
Articles are hosted by Taylor and Francis Online.
In this study, the characteristics of changes in reactivity due to increasing burnup of uranium-fueled fast reactors are analyzed. A new classification system for nuclear reactor cores based on their uncontrolled tendency for reactivity changes during burnup was introduced and the design-optimization strategy for any fast reactor core aimed at a minimized reactivity swing is outlined. The 235U feed-fuel enrichment level that minimizes the burnup reactivity swing of a sodium-cooled metallic-fueled core is 10% to 12.5% for an average target fuel burnup of 1% to 20% FIMA (fission of initial metal atom). The higher the target burnup of the system, the lower the feed-fuel enrichment level that minimizes swing. The minimum attainable swing for a 125-MW(thermal) metallic-fueled sodium-cooled core is found to be ∼200 pcm for 5% FIMA burnup and increases to ∼800 pcm for a system aiming at 10% FIMA. In general, if the target discharge burnup is doubled, the minimum attainable burnup reactivity swing quadruples. Any optimized minimum reactivity swing core will form a positive parabolic uncontrolled reactivity trajectory with burnup, where the beginning of cycle and end of cycle reactivities are equal. Uranium-fueled fast cores with minimized burnup reactivity swing are net consumers of fissile material, with a fissile conversion ratio in the range of 0.7 to 0.9.