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
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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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May 2025
Nuclear Technology
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Latest News
TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
G. R. Handley
Nuclear Technology | Volume 14 | Number 1 | April 1972 | Pages 71-75
Technical Paper | Session on Physics of Nuclear Materials Safeguards / Fuel | doi.org/10.13182/NT72-A31100
Articles are hosted by Taylor and Francis Online.
The criticality safety of water-sprinkled arrays of enriched uranium metal on 20-in. center-to-center spacing was investigated using KENO, a multigroup Monte Carlo criticality calculation program. The effects of array size and unit apparent density on the optimum-density interspersed water moderation were analyzed. It was shown that larger arrays of enriched uranium require a lower density of interspersed hydrogenous moderator for optimum moderation than do similar smaller arrays. Also, it was shown that when the density of dry uranium metal units is decreased from full density without changing the mass or the center-to-center spacing of the units, while maintaining optimum interspersed hydrogenous moderation, the neutron multiplication of the array at first decreases, then increases beyond that of the array of full density units. The initial decrease of the neutron multiplication of the array may not be true in general for all arrays.
