2018 | AFC ACCOMPLISHMENTS 75 exists diagonally across the channel box on walls 1 and 4. Notably, the fast neutron flux has a different behavior in which the maximum neutron flux occurs on walls 1 and 4. Finite element modeling of the channel box deformation due to the thermal- mechanical conditions was performed using both ABAQUS and BISON, and the results are shown in Figures 2 and 3. The channel box is predicted to undergo several millimeters of bowing due to the transient neutron irradiation-induced swelling of the SiC-SiC composite.This transient swelling behavior consists of a rapid increase to about ~2% volume increase at relevant BWR coolant temperatures and subsequently the magnitude of the swelling saturates, but with a neutron flux and temperature dependent saturation dose.The magnitude of the swelling is inversely proportional to temperature, however in this situation the temperature gradients did not dominate the results.The regions with higher neutron fluxes swelled sooner than those with lower levels, and this resulted in the lateral displacement. Since the circumferential temperature variation was fairly small, the transient swelling was predicted to saturate at very similar levels, which resulted in a relaxation of the lateral displacement.Thus, the maximum lateral displacement was predicted to be about 6.5 mm and occur at 8 to 11 days.Then over the course of the next year, the lateral displacement was predicted to reduce to about 0.3 mm. Figure 3. Plots comparing the lateral displacement magnitude predicted by BISON (left) and Abaqus (right).