Development of Helium Leak Testing System and Procedure for testing Welds of Steam Generator

The main function of Steam Generator (SG) in FBR is to extract the reactor heat through secondary sodium system and convert the feed water into superheated steam in the tubes of SG. The Steam Generator is a vertical, once through, shell and tube type heat exchanger with liquid sodium in the shell side and water/steam in the tube side. The highly reactive nature of sodium with water/steam requires that the sodium to water/steam boundaries of the steam generators mus t possess a high degree of reliability against failure. This paper highlights the experiences in helium leak-testing in vacuum mode to detect a leak rate of the order 6.66 X 10-9 Pa.m3/s, as specified.