The numerical results of non-dimensional ROT normalized by change of RITC showed superior CTLFA in the LPC based on NNH tests (a). The numerical results assuming 80% of the rated power in LPC showed that the CTLFA were superior to those of rated power to restrict the increase of ROT 7 ℃ smaller than the SAL in case that a stepwise temperature fluctuation of 10 ℃ was imposed on the RITC (b), which was referred from the design of commercial HTGR.