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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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Nuclear Science and Engineering
May 2025
Nuclear Technology
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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.
Tim D. Bohm, Edward P. Marriott, Mohamed E. Sawan
Fusion Science and Technology | Volume 72 | Number 4 | November 2017 | Pages 595-600
Technical Paper | doi.org/10.1080/15361055.2017.1350484
Articles are hosted by Taylor and Francis Online.
The ITER vacuum vessel (VV) is a double walled toroidal shaped stainless steel structure divided into nine 40 degree sectors. In the design process for the ITER blanket system (which provides shielding for the VV), determining integrated nuclear heating loads on the VV is important for cooling system sizing and determining localized nuclear heating on the VV is important for assessing thermal stress loads. Further, determining radiation damage, displacements per atom (dpa) on the VV, is important in meeting pressure vessel limits. Near the neutral beam injection (NBI) region of the VV (both sector 2 and sector 3), there are significant gaps and cut-outs in the blanket system to accommodate the 3 heating neutral beam (HNB) ports and the diagnostic neutral beam (DNB) port. These features lead to higher localized radiation loads. Previous analysis indicated high nuclear heating and dpa in the NBI region. The CAD based DAG-MCNP5 transport code was used to perform neutronics calculations in detailed, updated CAD models of the NBI region. For this work, a 40 degree model of sector 2 (which includes the HNB1 port, the DNB port, and the HNB2 port) was analyzed. Three design options were investigated which add shielding in the DNB port region by using port liners. Mesh tally maps of both nuclear heating and dpa are provided for the VV in the BM13-16 region. Peak dpa values ranged from 0.41–0.65 dpa. Two of the 3 design options investigated had peak dpa values near the DNB port within the ITER dpa limit of 0.5 dpa. Peak nuclear heating results ranged from 1.7 W/cm3 to 2.0 W/cm3. The mesh tally maps of nuclear heating have been provided to the ITER Organization for subsequent finite element engineering analysis. Preliminary analysis has shown the thermal stress levels are unacceptable with the added shielding. The results of this work are being used by the ITER Blanket and Tokamak Integration groups to assess the current design and modify blanket module (BM) design where needed if radiation loads are excessive.
