Deformation analysis of SiC-SiC channel box for BWR applications

Impact of Control Blade Insertion on the Deformation Behavior of SiC-SiC Channel Boxes in Boiling Water Reactors

“…The study presented here extends this previous study [14] and is aimed at understanding the effect of different control blade positions on the channel box bowing behavior and evaluating the severity of any interference between the control blade and channel box. The previous study used uncoupled computer codes to calculate the temperature and neutron flux distributions, which cause deformation of SiC-SiC from nonuniform thermal expansion and swelling.…”

“…An earlier study on SiC-SiC channel box deformation for BWR applications has shown that the channel box will undergo significant lateral bending, although most of the lateral bending is transient and can recover with straightening of the channel box at later times [14]. The lateral bending is caused by differential swelling across the width of the channel box.…”

“…A special coupled version of neutronics code MPACT (from the Consortium for Advanced Simulation of Light Water Reactors (CASL)) [15] and the sub-channel thermal hydraulic code CTF [16] were used for this analysis. Because a coupled methodology was used, the fast flux and temperature distributions predicted by MPACT/CTF are expected to be more accurate than the distributions predicted in the previous study [14], which used Serpent [17] and CTF in a decoupled fashion.…”

“…The details about the implementation of anisotropic properties, and the application of temperature and flux boundary conditions to the model are provided in Ref. [14].…”

“…In this analysis, the channel box top was allowed to freely move. It is important to note that in our prior publication [14], we have shown that when the top of the channel box is either partially or fully constrained in axial direction and rotation, stresses in the channel box rise to high magnitudes which will cause mechanical damage in the channel box [14]. Thus, mechanically constraining the top section of a SiC-SiC channel box is not considered favorable from the perspective of maintaining its structural integrity, and as such, has not been considered in the current analysis.…”