The second in a series of experiments using the High Temperature Lattice Test Reactor has been completed and provides information on the temperature dependence of k for a 233UO2-232ThO2-C fuel mixture. The infinite medium multiplication factor was found to decrease by 0.0350 ± 0.0015 from 20 to 1000°C. This result provides direct information necessary in the design of the control system and in the safety analysis for advanced high temperature gas cooled reactors.