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!
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Latest News
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Garry C. Gose, Thomas J. Downar, Karl O. Ott
Nuclear Technology | Volume 124 | Number 3 | December 1998 | Pages 284-290
Technical Note | Reactor Safety | doi.org/10.13182/NT98-A2927
Articles are hosted by Taylor and Francis Online.
The main-steam-line-break (MSLB) transient in a pressurized water reactor (PWR) is a core overcooling event that can result in a large positive reactivity insertion. In most analyses the shutdown margin is sufficiently large that the core does not return to critical. However, some researchers have reported an increase in the core power even though the core does not return to critical. A simplified kinetics model based on the prompt-jump-kinetics approximation is reported in new work, and a single delayed neutron group is used to explain the core power increase during subcriticality. Specifically, it is shown that the multiplication of the initial delayed-neutron source as predicted by the rate of change of the reactivity during the transient is the reason for the increase in power even though the core never returns to criticality after scram. The results are demonstrated using data from a RETRAN-03 model of a hot-zero-power MSLB analysis of the Three Mile Island unit 1 PWR.