Temperature analysis of the control rods at the scram shutdown of the HTTR; Evaluating by using measurement data at scram test of HTTR

Takada, Eiji*; Fujimoto, Nozomu; Matsuda, Atsuko*; Nakagawa, Shigeaki  

In the High Temperature Engineering Test Reactor (HTTR), since the primary circuit is very high at the high temperature test operation, the special alloy Alloy800H is used as the metallic material for cladding tubes and spines of the control rods to endure the temperature of 950 degrees centigrade. The control rod is supposed to be exchanged for the excess use of its temperature limit 900 degrees centigrade according to the strength data of Alloy800H. The scram shutdown by loss of off-site electric power at the high temperature test operation is assumed as an event of the temperature of the control rods to exceed 900 degrees centigrade. In this report, the temperature of the control rods is analyzed by using the measurement data of the rise-to-power test. The result of this analysis it is confirmed that the control rod temperature does not exceed its limitation value even after the most temperature raises event of the loss of off-site electric power at the high temperature test operation.