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Division members promote the advancement of mathematical and computational methods for solving problems arising in all disciplines encompassed by the Society. They place particular emphasis on numerical techniques for efficient computer applications to aid in the dissemination, integration, and proper use of computer codes, including preparation of computational benchmark and development of standards for computing practices, and to encourage the development on new computer codes and broaden their use.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
H. F. Martz, M. C. Bryson
Nuclear Science and Engineering | Volume 83 | Number 2 | February 1983 | Pages 267-280
Technical Paper | doi.org/10.13182/NSE83-A18219
Articles are hosted by Taylor and Francis Online.
Probabilistic risk assessments are increasingly being used to quantify the public risks of operating potentially hazardous systems such as nuclear power reactors. Such assessments require the quantification of the frequencies of various low-probability events. In performing these analyses, the risk analyst is often confronted with the dual problem of the appropriate data to be used to estimate the required frequencies and the development of the corresponding estimates. Often the problem reduces to one of how to combine (or pool) a variety of more or less applicable existing data sources. A Bayes/empirical-Bayes procedure is developed for combining as many as five different types of pertinent data. The five data types can be grouped under 1. analysis data, 2. similar operating data, 3. expert opinions, 4. historical operating data, 5. generic data. Example illustrations of each of these data types are given. The procedure is used to estimate the combined hourly failure rate of small manually operated sodium valves, such as those typically found in liquid-metal fast breeder reactor shutdown heat removal systems. Pertinent data sources include operating data from sodium test loops (similar operating data), expert opinion, operating data from the Experimental Breeder Reactor-II, and seven generic failure rate estimates for similar valves in both U.K. and U.S. operating light water power reactors. A final posterior distribution is produced that reflects the combined influence of all of these data. This distribution provides the required estimates and corresponding uncertainty bounds.