Reducing rod cusping effect in nodal expansion method calculations
01 Jan 2002-
TL;DR: In this paper, a method based on a physical equivalence was proposed to reduce the effect of rod cusping in neutronics calculations, where a strong discontinuity appears in the control rod worth versus rod insertion curve.
Abstract: In neutronics calculations control rods are modeled incrementing the cross sections by an amount interpolated in parametric tables. This amount depends on the average physical conditions of the node. For nodes containing the tip of a rod, a weighting factor must be applied in order to keep the correct reaction rate. Several methods exist to compute this factor. The simplest one is to take the volume fraction occupied by the tip of the control rod in the node. This method produces what is known as rod cusping: a strong discontinuity appears in the control rod worth versus rod insertion curve. The method developed here, based on a physical equivalence, allows a significant reduction of this effect.
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TL;DR: A moving mesh scheme based on hp-finite element method is proposed for the time dependent neutron diffusion equation that uses spatial meshes that change with the movement of the control rods avoiding the necessity of using equivalent material cross sections for the partially inserted cells.
17 citations
TL;DR: In this paper, a new solution for the control rod cusping problem in the three-dimensional pin-by-pin core calculation is proposed, and the current advanced nodal code resolves this issue by estimating...
Abstract: A new solution for the control rod cusping problem in the three-dimensional pin-by-pin core calculation is proposed in this paper. The current advanced nodal code resolves this issue by estimating ...
16 citations
TL;DR: It is demonstrated that the smoothly varying cross sections can be obtained by projecting the piecewise set of cross sections onto the set of Legendre polynomials up to a finite order and provided accurate results based on the C5G7-TD benchmark.
15 citations
TL;DR: In this paper, two heterogeneous nodal methods based on the Variational Nodal Method (VNM) with diffusion approximation in three-dimensional Cartesian geometry are investigated with a code named Violet-Het3D for PWR control rod cusping effect and pin-by-pin calculation.
10 citations
TL;DR: The NLG iteration method is extended to make it capable of transient calculations of 3-D heterogeneous problems, and a neighboring spectral index (NSI) weighting method is suggested as a tool for correcting the rod cusping phenomenon for rod ejection problems.
9 citations
References
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01 Sep 1992
TL;DR: Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1992 as discussed by the authors, Boston, Massachusetts, United States of America, Boston, MA
Abstract: Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1992.
37 citations
TL;DR: The TRAC-PF1/NEM code as mentioned in this paper uses closely coupled 3D thermal-hydraulics and 3D core neutronics transient models to simulate the vessel and a 1-D simulation of the primary system.
24 citations
Dissertation•
01 Jan 1984
16 citations
Journal Article•
9 citations