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
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
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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
Mar 2025
Jul 2024
Latest Journal Issues
Nuclear Science and Engineering
March 2025
Nuclear Technology
Fusion Science and Technology
April 2025
Latest News
Nuclear News 40 Under 40 discuss the future of nuclear
Seven members of the inaugural Nuclear News 40 Under 40 came together on March 4 to discuss the current state of nuclear energy and what the future might hold for science, industry, and the public in terms of nuclear development.
To hear more insights from this talented group of young professionals, watch the “40 Under 40 Roundtable: Perspectives from Nuclear’s Rising Stars” on the ANS website.
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.