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
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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.
Kazuya Idemitsu, Ken-ichiro Kuwata, Hirotaka Furuya, Yaohiro Inagaki, Tatsumi Arima
Nuclear Technology | Volume 118 | Number 3 | June 1997 | Pages 233-241
Technical Paper | Radioactive Waste Management | doi.org/10.13182/NT97-A35364
Articles are hosted by Taylor and Francis Online.
Diffusivities of cesium in a water-saturated mortar were measured in an attempt to investigate the migration of radionuclides into the matrix of the mortar. The measured penetration profiles of the tracer were composed of two parts. There was a steep slope near the surface and a gradual slope in the mortar interior. This kind of profile has been reported by many researchers. This profile was successfully explained by considering two diffusion paths in the mortar. One diffusion path was through fissures with a width of a few microns, and the other was through the intact mortar network of submicron pores. This model was supported by autoradiography of some cross sections of a mortar specimen. The volume of submicron pores was ∼95% of the total pore volume in the mortar. The order-of-magnitude values for the apparent diffusivities for cesium were 10−2 m2/s through the fissure and 10−14 m2/s through the network of pores. The effective diffusion coefficient for cesium was estimated at ∼10−13 m2/s by using the apparent diffusivities through the fissures, the aperture of the fissures, and the fissure interval. Geometric factors in the two paths were also estimated by using the apparent diffusivity and diffusion coefficients for free ions; they were estimated at ∼0.13 for fissures and ∼0.01 for the mortar matrix. This model was applied to other researchers’ data to estimate the effective diffusion coefficient. This model and estimation method show the consistency of the data from through-diffusion and penetration experiments.