[en] Zircaloy-sheathed Type-K thermocouples, fabricated to a diameter of 0.61 mm and flattened to a thickness of 0.43 mm are described. These instruments are embedded on the surface of electrically-heated fuel rod simulators and used to obtain data for a program intended to characterize the perturbing effect of surface-mounted fuel rod cladding surface thermocouples. Differences between drawn and swaged thermocouples, which led to the drawing technique used in fabrication, are discussed, and the method of attachment of the flattened thermocouples to zircaloy-clad fuel rod simulators is illustrated. Laboratory test results of blowdown/reflood simulation, freeze-point calibration, and response time testing of prototype instruments are presented