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Blowdown/reflood testing of two heater rods containing laser welded thermocouple attachments is described. Two series of tests were conducted, one of three and another of nine blowdowns. Test parameters were controlled such that the blowdown/reflood cycles duplicated those predicted for the LOFT reactor. Thermocouple performance throughout the test series was very good in that the only failures observed were caused by bowing of the heater rod. Data from all tests are included as are photographs of laser welds taken at various times during the test series. Although heater rod bowing did cause failure of some of the welds, actual fuel pins are restrained and thus not expected to bow to this extent. When weld failure does occur it appears in the form of a separation at the bond between the Titanium fillet and Zircaloy. This does not impair either the performance or the integrity of the fuel cladding in any way.