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Division Spotlight
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.
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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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.
R. B. Walton, T. D. Reilly, J. L. Parker, J. H. Menzel, E. D. Marshall, L. W. Fields
Nuclear Technology | Volume 21 | Number 2 | February 1974 | Pages 133-148
Technical Paper | Instrument | doi.org/10.13182/NT74-A31369
Articles are hosted by Taylor and Francis Online.
The applicability of portable instruments for rapid nondestructive verification of the enrichment of UF6 in cylinders has been tested on a large number of Types-30 and -5A cylinders. Three basic techniques were used: (a) gamma-ray counting with Nal, combined with ultrasonic measurement of cylinder wall thickness, (b) passive-neutron counting, and (c) active-neutron interrogation with thermal neutrons from a radioactive neutron source. The accuracy of the gamma-ray method was ∼5% (1σ) for Type-30 cylinders of UF6 and 2% for highly enriched UF6 in Type-5A cylinders; however, the method occasionally failed for Type-30 cylinders because of background from nonvolatile daughters of 238U plated on the cylinder walls. The standard deviation of enrichments of 110 Type-30 cylinders, derived from passive-neutron counting data by assuming a constant 235U/234U ratio, is The response of the active system increases almost linearly with enrichment up to ∼2.5% 235U and then saturates at ∼4%.
