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
Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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.
K. Tasaka, H. Adachi, M. Sobajima, K. Soda, M. Suzuki, M. Okazaki, M. Shiba
Nuclear Technology | Volume 45 | Number 2 | September 1979 | Pages 121-139
Technical Paper | Reactor | doi.org/10.13182/NT79-A32303
Articles are hosted by Taylor and Francis Online.
To evaluate upper head injection system (UHIS) performance during a postulated loss-of-coolant accident (LOCA) in a pressurized water reactor (PWR), ten UHIS tests were conducted at the ROSA-II test facility. The experimental results were different from the expected UHIS performance in the following points. First, flashing took place in the upper head and a mixture level was formed before UHIS actuation. Second, emptying of the upper head was observed immediately after UHIS shut off. Third, part of the water which flowed down from the upper head, penetrated into the core and contributed to core cooling at the top part of the core, however, most of the water flowed out through the broken loop hot leg. In the case of higher injection water temperature (∼120°C), the fluid behavior in the pressure vessel differed significantly from the results for the low injection water temperature (∼20°C), and the core cooling was remarkably improved. Therefore, high-temperature UHIS water is recommended for effective core cooling. The results described above are due to the following physical phenomena: