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Division Spotlight
Accelerator Applications
The division was organized to promote the advancement of knowledge of the use of particle accelerator technologies for nuclear and other applications. It focuses on production of neutrons and other particles, utilization of these particles for scientific or industrial purposes, such as the production or destruction of radionuclides significant to energy, medicine, defense or other endeavors, as well as imaging and diagnostics.
Meeting Spotlight
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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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February 2025
Nuclear Technology
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Latest News
Trump picks former N.Y. congressman for NNSA administrator
Williams
President Trump has selected Brandon Williams to head the Department of Energy’s National Nuclear Security Administration, pending confirmation by the U.S. Senate.
Williams is a former one-term congressman (R., N.Y.),from 2023 to the beginning of 2025. Prior to political office he served in the U.S. Navy. Williams’s run for office gained attention in 2022 when he defeated fellow navy veteran Francis Conole, a Democrat, but he lost the seat last November to Democrat John Mannion.
“I will be honored to lead the tremendous scientific and engineering talent at NNSA,” Williams said, thanking Trump, according to WSYR-TV in Syracuse, N.Y.
Alexander Lindsay, Roy Stogner, Derek Gaston, Daniel Schwen, Christopher Matthews, Wen Jiang, Larry K. Aagesen, Robert Carlsen, Fande Kong, Andrew Slaughter, Cody Permann, Richard Martineau
Nuclear Technology | Volume 207 | Number 7 | July 2021 | Pages 905-922
Technical Paper | doi.org/10.1080/00295450.2020.1838877
Articles are hosted by Taylor and Francis Online.
Efficient solution via Newton’s method of nonlinear systems of equations requires an accurate representation of the Jacobian, corresponding to the derivatives of the component residual equations with respect to the degrees of freedom. In practice these systems of equations often arise from spatial discretization of partial differential equations used to model physical phenomena. These equations may involve domain motion or material equations that are complex functions of the systems’ degrees of freedom. Computing the Jacobian by hand in these situations is arduous and prone to error. Finite difference approximations of the Jacobian or its action are prone to truncation error, especially in multiphysics settings. Symbolic differentiation packages may be used, but often result in an excessive number of terms in realistic model scenarios. An alternative to symbolic and numerical differentiation is automatic differentiation (AD), which propagates derivatives with every elementary operation of a computer program, corresponding to continual application of the chain rule. Automatic differentiation offers the guarantee of an exact Jacobian at a relatively small overhead cost. In this work, we outline the adoption of AD in the Multiphysics Object Oriented Simulation Environment (MOOSE) via the MetaPhysicL package. We describe the application of MOOSE’s AD capability to several sets of physics that were previously infeasible to model via hand-coded or Jacobian-free simulation techniques, including arbitrary Lagrangian-Eulerian and level-set simulations of laser melt pools, phase-field simulations with free energies provided through neural networks, and metallic nuclear fuel simulations that require inner Newton loop calculation of nonlinear material properties.