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.
Explore membership for yourself or for your organization.
Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
July 2025
Latest News
Hash Hashemian: Visionary leadership
As Dr. Hashem M. “Hash” Hashemian prepares to step into his term as President of the American Nuclear Society, he is clear that he wants to make the most of this unique moment.
A groundswell in public approval of nuclear is finding a home in growing governmental support that is backed by a tailwind of technological innovation. “Now is a good time to be in nuclear,” Hashemian said, as he explained the criticality of this moment and what he hoped to accomplish as president.
Udo Graf
Nuclear Science and Engineering | Volume 129 | Number 3 | July 1998 | Pages 305-310
Technical Paper | doi.org/10.13182/NSE98-A1984
Articles are hosted by Taylor and Francis Online.
The German ATHLET thermal-hydraulic system code has been coupled with a two-dimensional module simulating the downcomer of a pressurized water reactor. To be efficient, this coupling had to be implicit in time. The countercurrent two-phase flow of water and steam in the downcomer of a reactor pressure vessel was simulated using this combined code system. The implicit coupling procedure, as well as the results of a postcalculation of an experiment of the Upper Plenum Test Facility, are described.