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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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Latest News
NRC updating GEIS rule for new nuclear technology
The Nuclear Regulatory Agency is issuing a proposed generic environmental impact statement (GEIS) for use in reviewing applications for new nuclear reactors.
In an April 17 memo, NRC secretary Carrie Safford wrote that the commission approved NRC staff’s recommendation to publish in the Federal Register a proposed rule amending 10 CFR Part 51, “Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions.”
Michael Jarrett, Brendan Kochunas, Edward Larsen, Thomas Downar
Nuclear Science and Engineering | Volume 193 | Number 12 | December 2019 | Pages 1291-1309
Technical Paper | doi.org/10.1080/00295639.2019.1627176
Articles are hosted by Taylor and Francis Online.
A new method for calculating anisotropic radial transverse leakage (TL) in a two-dimensional (2D)/one-dimensional (1D) transport method is derived and implemented in MPACT. This method makes use of parity in the polar angle only to form the 2D transport equations for the 2D/1D method. The even-parity component is solved on a fine mesh using the method of characteristics (MOC), while the odd-parity component is solved on a coarse mesh using S. The anisotropic radial TL on the coarse cell boundaries is calculated by combining the even- and odd-parity components. The new method is faster than a similar previous method because it delegates half of the work required to calculate the solution of the 2D transport problem to a coarse-mesh S solver, which is more than ten times faster than the fine-mesh MOC solver. The results show that the accuracy of the new method is equivalent to that of the previously implemented method for anisotropic TL, with a significant speedup. With azimuthally isotropic TL, the new method reduces the computational overhead compared to the standard method from 58% to 5% for the three-dimensional (3D) C5G7 benchmark problems. With azimuthally anisotrop\ic TL using Fourier expansion, the new method reduces the overhead from 84% to 37%. This is important because the accuracy of the 2D/1D method is limited by the isotropic TL approximation. With anisotropic TL, the accuracy of 2D/1D is equivalent or comparable to 3D transport, but there is a significant computational cost associated with calculating the anisotropic TL. The method presented provides a faster way to calculate the anisotropic TL, giving the 2D/1D method significantly increased accuracy with only a modest increase in computational requirements compared to isotropic 2D/1D.