[en] LOFT thermocouple response data are presented from the first zircaloy clad heater rod tests conducted in the Blowdown Facility which were intended to simulate coolant and cladding temperature conditions expected during the LOFT loss-of-coolant experiments. Comparison is made to previous stainless steel clad heater rod tests and discussion of the application of these results for correcting LOFT cladding temperature measurements is presented