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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.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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!
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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.
T. C. Chawla, B. M. Hoglund
Nuclear Science and Engineering | Volume 44 | Number 3 | June 1971 | Pages 320-344
Technical Paper | doi.org/10.13182/NSE71-A20165
Articles are hosted by Taylor and Francis Online.
The flow transients as initiated by rapid gas release are studied both experimentally and analytically. The mathematical model developed considers a multiple pin failure in a fast-reactor subassembly. In formulating the model, it is assumed that the released gas fills the subassembly cross section uniformly and that the coolant flow is incompressible. The model considers the inertial contribution of the liquid columns beyond the pin assembly, as well as the three-dimensional flow effects in the inlet and outlet plenums. In the application of the model to out-of-pile simulation loops, or in-pile test loops, points of departure in hydraulic simulation of the actual reactor conditions can be taken into account. A quantitative criterion for valid application of the model is obtained in terms of breach size, number of pins ruptured, initial gas plenum pressure and temperature, and subassembly operating conditions. The predictions of the flow transients obtained by means of the model agree well with the experimental data. An example of the application of the model to a reactor configuration is given using an FFTF fuel subassembly.