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Conference Spotlight
2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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Ho Nieh, TVA board members, and nuclear fuel recycling bill head to Senate floor
Nieh
Ho Nieh, the Trump administration’s nominee to be a member of the Nuclear Regulatory Commission, and four new board members of the Tennessee Valley Authority were approved in a vote today by the Senate Environment and Public Works Committee and head to the Senate floor for a final vote.
The committee also voted to advance to the Senate floor the Nuclear REFUEL Act of 2025 (S. 2082), which would smooth the regulatory pathway for recycling used nuclear fuel.
President Donald nominated Nieh on July 30 to serve as NRC commissioner for the remainder of a term set to expire June 30, 2029, which was held by former NRC commissioner Chris Hanson, who Trump fired in June.
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.
