The development of technology of Be/CuCrZr joining using induction brazing

Abstract

The article describes the method of vacuum induction brazing of beryllium tiles covering the surface of the first wall of ITER. To prevent the formation of brittle intermetallic and preservation of the mechanical properties of the CuCrZr alloy, it leads to the need to minimize the brazing temperature and time of the brazing cycle. Designed according to the results of calculations and optimized in experiments, the inductor allows heating locally the beryllium tile/CuCrZr alloy region with required heating rate. With the aim to minimize brazing temperature this paper presents the result of selection of the optimal eutectic of STEMET 1101 brazing alloy thereby reducing the temperature of the brazing to 680 °C. To fix each of the beryllium tiles during the brazing cycle, a unique clamping tool was developed and applied. As a confirmation of the reliability of this method, along with the results of ultrasonic testing of brazed joints, the paper presents the successful results of high heat flux testing of the mock-ups throughout the full life-time of the ITER first wall panels (15,000 heat cycles).