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
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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.
Colin George Windsor, Thomas Noel Todd, David Leonard Trotman, Michael Edward Underhill Smith
Fusion Science and Technology | Volume 32 | Number 3 | November 1997 | Pages 416-430
Technical Paper | Plasma Control Issues for Tokamaks | doi.org/10.13182/FST97-A5
Articles are hosted by Taylor and Francis Online.
The plasma position and shape on the COMPASS-D tokamak have been controlled simultaneously with a 75-kHz bandwidth, hard-wired, real-time neural network. The primary network operates with up to 48 selected magnetic inputs and has been used in the vertical position control loop to control the position of the upper edge of the plasma at the radius of a reciprocating Langmuir probe and to keep this constant during a programmed shape sequence. One of the main advantages of neural networks is their ability to combine signals from different types of diagnostics. Two coupled networks are now in use on COMPASS-D. A dedicated soft-X-ray network has been created with inputs from 16 vertical and 16 horizontal camera channels. With just four hidden units, it is able to accurately determine three output signals defining the plasma core radius, vertical position, and elongation. These signals are fed to the primary network along with selected magnetic inputs and four poloidal field coil control current inputs. The core data are expected to help characterize the equilibrium by providing information on the Shafranov shift and gradient of elongation, related to the equilibrium parameters p and li. This network, with 15 hidden units, is able to define 10 outputs capable of giving a parameterized display of the plasma boundary. This paper describes results from several networks trained on various combinations of inputs with (a) simulated inputs and output values, where the precision of the network can be tested; (b) experimental inputs and calculated output values, where operational precision can be tested; and (c) hardware networks, where real-time performance can be tested. The results confirm that the neural network method is capable of giving excellent precision in tokamak boundary reconstruction but that the necessary accuracy in the experimental inputs for this task is not easily achieved.