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Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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2024 ANS Annual Conference
June 16–19, 2024
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.
I. Pázsit, M. Ceder, Z. Kuang
Nuclear Science and Engineering | Volume 148 | Number 1 | September 2004 | Pages 67-78
Technical Paper | doi.org/10.13182/NSE04-A2442
Articles are hosted by Taylor and Francis Online.
In future planned accelerator-driven subcritical systems, as well as in some recent related experiments, the neutron source to be used will be a pulsed accelerator. For such cases the application of the Feynman-alpha method for measuring the reactivity is not straightforward. The dependence of the Feynman Y(T) curve (variance-to-mean minus unity) on the measurement time T will show quasi-periodic ripples, corresponding to the periodicity of the source intensity. Correspondingly, the analytical solution will become much more complicated. One can perform such a pulsed Feynman-alpha measurement in two different ways: either by synchronizing the start of each measurement block with the pulses ("deterministic pulsing") or by not synchronizing ("random pulsing"). The variance-to-mean has been derived analytically for both cases and reported briefly in previous publications. However, two different methods were used and the two cases were reported separately. In this paper we give a unified treatment and a comparative analysis of the two cases. It is found that the stochastic pulsing leads to an analytic solution that is much simpler than that for the deterministic case, and the relationship between the pulsed and continuous source is much more straightforward than in the deterministic case. However, the amplitude of the ripples, constituting a deviation of the pulsed Feynman Y curve from the smooth curve corresponding to the traditional constant source case, is much larger for the stochastic pulsing than for the deterministic one. The reasons for this are also analyzed in the paper. The results are in agreement with recent measurements, made by other groups in the European Community-supported project MUSE.