| In joining spacers and pads on the cladding tube of the Candu type nuclear fuel pin, brazing is employed with a filler metal of Be. It is well known that the mechanical properties of the joint depends significantly on the thickness of the filler metal as well as on the brazing time and temperature. In the present study, it was attempted to find the optimum thickness of the filler metal which could give a good joint between thin Zr-4 tube and the spacer. Furthermore, the corrosion rate of the brazed area was examined in conjunction with the microstructures of the brazed zone. Brazing was carried out by induction heating for 20 seconds at 1000℃-1040℃ which is just above the eutectic point of α-Zr-ZrBe₂, the best result was obtained with the thickness of the filler metal in the range of 8-10 ㎛, where the joint strength was 20㎏/㎟. The basket weave structure was observed in the heat affected zone in brazing. The corrosion rate of this area was lower than that of the annealed structure. |
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