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
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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.
William S. Charlton, William D. Stanbro
Nuclear Technology | Volume 136 | Number 1 | October 2001 | Pages 24-36
Technical Paper | Fuel Cycle and Management | doi.org/10.13182/NT01-A3226
Articles are hosted by Taylor and Francis Online.
A methodology for determining alternate nuclear material (237Np, 241Am, and 243Am) concentrations in spent nuclear fuel based on the use of various monitors was developed and validated for use with several pressurized water reactor fuels. The monitors studied included the fuel burnup, the total plutonium concentration, the 240Pu/239Pu isotopic ratio, the 148Nd/238U isotopic ratio, and the 137Cs activity. Calculations were performed using the HELIOS-1.4 lattice physics code for spent fuel from the Mihama Unit 3, Genkai Unit 2, and Calvert Cliffs Unit 1 reactors. These calculations were compared to measured values for the fuel. It was determined that the 240Pu/239Pu isotopic ratio and the 137Cs activity were the most useful and accurate for use in predicting alternate nuclear material concentrations at reprocessing facilities for safeguards purposes. Based on these comparisons, it was determined that measurements of these monitors would allow for determination of 237Np, 241Am, and 243Am concentrations to within ±4, ±6, and ±15%, respectively. It is suggested that these uncertainties may be decreased through improvements in measurement techniques and additional benchmarking. These monitors may be used to provide an accurate prediction of the concentrations of the alternate nuclear materials while decreasing the need for direct measurement of these isotopes. This will translate into a monetary savings for reprocessing facility safeguards.
