Thermal-Hydraulic Analysis of Core Shroud Crack for Chinshan BWR/4 Unit 2 Using RETRAN-02/MOD5

The RETRAN analyses of three areas of thermal-hydraulic concerns are presented. The first evaluated whether a 360-deg through-wall crack could be detected based on system response with leakage through the crack. The second analysis was to identify the hydraulic load on the shroud and possible consequences early in the main steam-line break. The last was the evaluation of the thermal limit (CPR) of limiting transients with leakage. Some of the analyses were used for justification of continued operation of the current cycle, and some will be useful in the evaluation of the repair design.