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.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Nov 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
Fusion Science and Technology
November 2025
Latest News
Nuclear power’s new rule book: Managing uncertainty in efficiency, safety, and independence
The U.S. nuclear industry is standing at its most volatile regulatory moment yet—one that will shape the trajectory and the safety of the industry for decades to come. Recent judicial, legislative, and executive actions are rewriting the rules governing the licensing and regulation of nuclear power reactors. Although these changes are intended to promote and accelerate the deployment of new nuclear energy technologies, the collision of multiple legal shifts—occurring simultaneously and intersecting with profound technological uncertainties—is overwhelming the Nuclear Regulatory Commission and threatening to destabilize investor and industry expectations.
Zhaopeng Zhong, Thomas J. Downar, Yunlin Xu, Mark D. DeHart, Kevin T. Clarno
Nuclear Science and Engineering | Volume 158 | Number 3 | March 2008 | Pages 289-298
Technical Note | doi.org/10.13182/NSE06-24TN
Articles are hosted by Taylor and Francis Online.
The coarse-mesh finite difference (CMFD) formulation is applied as an efficient means of acceleration of the heterogeneous whole-core transport calculation. The CMFD formulation enables dynamic homogenization of the cells during the iterative solution process such that the heterogeneous transport solution can be preserved. Dynamic group condensation is also possible with a two-level CMFD formulation involving alternate multigroup and two-group calculations. The two-dimensional discrete ordinates (SN) method is used as the kernel to generate the heterogeneous solution; the CMFD solution provides the SN kernel with much faster convergence of fission and scattering source distributions. In this paper, the two-level CMFD acceleration has been tested using the VENUS-2 two-dimensional whole-core model; it is shown that the number of SN transport sweeps can be reduced by a factor of about 10 while exactly reproducing the original transport solution. The second level of CMFD acceleration is also significant in reducing the computation time. The application of the CMFD formulation in arbitrary geometry demonstrates that CMFD also works well for irregular geometries.
