ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
Meeting Spotlight
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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!
Latest Magazine Issues
Jan 2025
Jul 2024
Latest Journal Issues
Nuclear Science and Engineering
February 2025
Nuclear Technology
Fusion Science and Technology
Latest News
How to talk about nuclear
In your career as a professional in the nuclear community, chances are you will, at some point, be asked (or volunteer) to talk to at least one layperson about the technology you know and love. You might even be asked to present to a whole group of nonnuclear folks, perhaps as a pitch to some company tangential to your company’s business. So, without further ado, let me give you some pointers on the best way to approach this important and surprisingly complicated task.
R. A. Karam, J. E. Marshall, K. D. Dance
Nuclear Science and Engineering | Volume 43 | Number 1 | January 1971 | Pages 5-26
Technical Paper | doi.org/10.13182/NSE71-A21241
Articles are hosted by Taylor and Francis Online.
The heterogeneity and sodium void effects in ZPR-6 Assembly 5, a 2700-liter UC core, were analyzed using ENDF/B data. The cross-section sets used were generated for the homogeneous composition of this assembly, corrected for resonance spatial self-shielding in 238U via equivalence theory, and weighted with the fine structure of the fluxes in the unit-cell. Bilinear weighting with the unit-cell fine structure of the real and adjoint fluxes was also performed. The calculated critical mass was 18% greater than the measured value. The calculated keff of the as-built system was 0.988. The calculated ratio of fission in 238U to fission in 235U was, depending on the loading pattern in the unit-cell, 13 to 26% less than the measured value. The calculated ratio of capture in 238U to fission in 235U was 7 to 10% greater than the measured value. The measured reactivity difference between a small homogeneous sample and another matched plate heterogeneous sample was a factor of 4 greater than the calculated value, indicating the analytical tools used for treating the heterogeneity effects were not adequate. The reactivity difference between homogeneous and rodded samples was nil. The calculated reactivity worths of 235U samples are in a reasonable agreement with measurements. The predicted 238U reactivity worth was 15 to 20% greater than the measured value. The measured sodium-void coefficient was about 25% greater than the calculated value. The magnitude of this coefficient is quite sensitive to the particular loading pattern in the unit-cell and it is strongly dependent on the effective capture rates in 238U. The dependence of the void coefficient on loading patterns is predictable in direction but not magnitude. The void coefficient in a rodded sample was the same as that in a plate heterogeneous sample. The void coefficient in a homogeneous sample was 56% greater than that in the rodded or the plate samples.
