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.
Kevin Tsai, Austin Fleming, Colby Jensen, Ryan Fronk, Troy Unruh, Eric Larsen, Cody Race (INL)
Proceedings | Nuclear Plant Instrumentation, Control, and Human-Machine Interface Technolgies (NPIC&HMIT 2019) | Orlando, FL, February 9-14, 2019 | Pages 612-617
Fast-response Self-Powered Neutron Detectors (SPNDs) demonstrated good performance in providing live-time, in-pile neutron flux measurements during transient operations at the Transient Reactor Test (TREAT) Facility at Idaho National Laboratory (INL) in the early 1990s. Two types of emitters for the fast-response SPNDs were tested?hafnium and gadolinium. Both types of SPNDs emitters generate electrical current which can be correlated to neutron flux. Gamma rays emitted from (n, ?) reactions in the emitter eject electrons by Compton scattering, which in turn induces the signal current. Current is also induced within the signal wire, thereby, necessitating a second compensation wire. The currents are subsequently measured using a pair of electrometers to provide time-resolved localized neutron flux measurement. These transient-response SPNDs have been reinserted into TREAT in 2018 to measure neutron flux levels and in-core power response during rapid reactivity insertion transients to support the recent TREAT resumption of operations. The objective of these experiments is to establish the instrumentation capability provided by fast-response SPNDs at INL to support transient irradiations. Testing of the SPNDs included the use of a gadolinium and a hafnium SPND in temperature limited and clipped reactivity insertion transients. The full-width half-maximum (FWHM) of the transient response measured from the SPNDs was compared with the TREAT ex-core neutron detectors as an initial step of analyzing the performance of the SPNDs and accompanying electronics. These SPNDs will be used as a benchmark for the development and fabrication of future SPNDs for deployment in transient irradiation tests.
