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Division Spotlight
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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!
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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.
B.D. Boyer, J. W. Hartzell,† S. Lider, G. E. Robinson, A. J. Baratta, A. J. Roscioli
Nuclear Technology | Volume 103 | Number 2 | August 1993 | Pages 206-219
Technical Paper | Nuclear Reactor Safety | doi.org/10.13182/NT93-A34844
Articles are hosted by Taylor and Francis Online.
The effects of condensation steam quenching in modeling two-phase flow phenomena during a nuclear reactor transient are studied. The RETRAN-02-MOD002 code, with three field equations and a nonequilibrium pressurizer model option, and the TRAC-BF1 code, with six field equations, predicted plant response to a boiling water reactor plant test of a main steam isolation valve closure without safety relief valve opening. The basic RETRAN-02-MOD002 field equations cannot model steam quenching by condensation. However, by activating the nonequilibrium modeling option of the basic RETRAN-02-MOD002 code and by inputting appropriate interfacial heat transfer coefficients, steam quenching by condensation was calculated. This approach gave results closer to those obtained with the test data. The two TRAC-BFI models used two different methods of tracking water level to approximate the condensation quenching effect. Because the void fraction changes too gradually, the calculation without the TRAC two-phase water level tracking option overquenched the pressure and filled the vessel with too much water. However, because the void fraction changes virtually instantaneously (as it does in the plant), the TRAC two-phase water level tracking option’s prediction of the quenching of the pressure was 50% closer to the data than was any RETRAN-02-MOD002 calculation, and it followed the water level almost as well as the RETRAN-02-MOD002 best-estimate case. Both codes overpredicted the pressure spike.
