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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.
Gary R. Smolen, Raymond C. Lloyd, Tomozo Koyama
Nuclear Technology | Volume 107 | Number 3 | September 1994 | Pages 326-339
Technical Paper | Nuclear Criticality Safety | doi.org/10.13182/NT94-A35011
Articles are hosted by Taylor and Francis Online.
Critical experiments were performed at the Pacific Northwest Laboratory-Critical Mass Laboratory from 1985 to 1987 with mixed Pu+U nitrate solutions in annular geometry. The 25.4-cm-diam central region of the annular vessel contained various inserts, such as a bottle containing fissile solution and borated-concrete and cadmium-covered polyethylene annular inserts. The fissile solution concentrations ranged from 47 to 226g Pu/ℓ with Pu/Pu+U ratios of 1.0, 0.5, and 0.2. The criticality data were used to validate two versions of the SCALE computer code system (SCALE-4 and SCALE-2). The analyses were performed with the 27-energy-group cross-section library, derived from the Evaluated Nuclear Data File B-Version IV. Computer models were prepared to accurately simulate all significant materials that would affect the system reactivity. The average calculated keff for the 18 experiments was 1.008 (σ = 0.006) with SCALE-4 and 1.004 (σ = 0.006) with SCALE-2. Overall, the range of calculated keff’s varied from 0.990 to 1.017. The results of the validation calculations indicate that the SCALE computer code system is capable of accurately modeling Pu+U nitrate. solutions in annular geometry.