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Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
Meeting Spotlight
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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Latest News
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.
C. D. Bowman, D. C. Bowman, T. Hill, J. Long, A. P. Tonchev, W. Tornow, F. Trouw, Sven Vogel, R. L. Walter, S. Wender, V. Yuan
Nuclear Science and Engineering | Volume 159 | Number 2 | June 2008 | Pages 182-198
Technical Paper | doi.org/10.13182/NSE159-182
Articles are hosted by Taylor and Francis Online.
High-resolution Bragg-edge transmission measurements were conducted on granular as well as solid samples of graphite to understand the basis for a bulk measurement of the diffusion length 24% larger than predicted by MCNP5 for bulk reactor-grade graphite. High resolution enabled a measurement of the total diffraction cross section from 1 to 200 meV. This was subtracted from the total cross section to find the inelastic cross section in the same energy range. Small-angle scattering, which has been thought to contribute to the total cross section in the region of the lowest Bragg edge, is shown not to be present in our measurement or in those of others claiming to find it. Instead, neutron total reflection from the surface of graphite microcrystals is shown to contribute to the cross section at low energies. Reactor-grade graphite is shown to have an inelastic scattering cross section over most of the energy range larger by at least 10 than the nearly perfect crystal structure of pyrolytic graphite. The ratio of inelastic scattering to diffraction at 25 meV for our graphite is inferred to be twice as large as that of graphite manufactured 50 yr ago, and we believe that our larger diffusion coefficient is rooted in this difference. The distortions in the microcrystalline structure introduced in the manufacturing of the graphite studied here at 24°C are found to be equivalent to the uncertainty in atom positions seen in heating perfect crystal graphite to a temperature of ~1800°C.