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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
Nuclear and Emerging Technologies for Space (NETS 2023)
May 7–11, 2023
Idaho Falls, ID|Snake River Event Center
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
The blossoming of cooperation between the U.S. and Canada
The United States and Canadian nuclear industries used to be an example of how two independent teams of engineers facing an identical problem—making electricity from uranium—could come up with completely different answers. In the 1950s, Canada began designing a reactor with tubes, heavy water, and natural uranium, while in the U.S. it was big pots of light water and enriched uranium.
But 80 years later, there is a remarkable convergence. The North American push for a new generation of nuclear reactors, mostly small modular reactors (SMRs), is becoming binational, with U.S. and Canadian companies seeking markets and regulatory certification on both sides of the border and in many cases sourcing key components in the other country.
Risto Vanhanen
Nuclear Science and Engineering | Volume 181 | Number 1 | September 2015 | Pages 60-71
Technical Paper | doi.org/10.13182/NSE14-105
Articles are hosted by Taylor and Francis Online.
It is not uncommon that the covariances of multigroup nuclear data do not obey the sum rules of nuclear data. We present a matrix nearness problem of finding a nearest symmetric matrix with given null vectors and solve it when the distance is measured in the Frobenius norm. The problem appears to be new. We propose that the method should be used to find nearest consistent multigroup covariance matrices with respect to the sum rules of redundant nuclear data.
If the multigroup covariances cannot be easily interpreted in a consistent manner, there is some ambiguity in choosing values for the covariances that are not explicitly mentioned. We present and compare a simple and a heuristic characterization method.
Three practical examples are processed and analyzed: relative covariances of cross sections of 9440Zr and absolute covariances of cross sections of 5024Cr and 23290Th. We demonstrate that satisfactory results can be achieved.
We discuss the properties of the proposed method and the characterization methods and suggest possible improvements. The methods can be used as a part of a quality assurance program and might be valuable additions to nuclear data processing codes.
