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
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
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.
M. A. Hassan, K. Rehme
Nuclear Technology | Volume 52 | Number 3 | March 1981 | Pages 401-414
Technical Paper | Fuel Cycle | doi.org/10.13182/NT81-A32714
Articles are hosted by Taylor and Francis Online.
The influence of spacer grids on the heat transfer in gas-cooled rod bundles was determined experimentally for the first time over a wide range of parameters. The experimental investigations were carried out with a smooth and a rough rod bundle for Reynolds numbers between 600 and 2 × 105. The measured range of Reynolds numbers covered the transition from laminar to turbulent, the transition from hydraulically smooth to rough, and fully rough flows. In gas cooling, artificial roughnesses on the rod surfaces are used to disturb the viscous sublayer, which acts as an insulator because of the low thermal conductivity of gases. For this investigation, a two-dimensional rectangular roughness was used, which had an optimum heat transfer characteristic. The blockage factor ∊ was varied between 25 and 35%. These values are typical of flow blockages due to spacer grids in gas-cooled fast reactors. The measurements were carried out from 10 Dh upstream to 33 Dh downstream of the spacer grid. The measured range covered the zone of heat transfer influenced by the spacer grid. The measurements showed heat transfer to be improved by spacer grids in all cases investigated. On the basis of the measurements, empirical correlations could be established for the influence of the spacer grid on heat transfer in terms of the measured parameters, i.e., Reynolds number, blockage factor, and the type of heat transfer surface. These empirical correlations can be directly used in computer codes for analysis of the thermodynamics and fluid dynamics of gas-cooled rod bundles.
