Weld overlay of BWR flawed piping

The occurrence of intergranular stress corrosion cracking (IGSCC) in the reactor water clean-up (RWCU) system and the recirculation systems in Boiling Water Reactors (BWR) has plagued utilities in the United States over the past few years. There are those who believe that if significant IGSCC exists, the only long-term solution is to replace the affected piping. Nevertheless, there are also those who contend that if only moderate flaws exist, the application of induction heating stress improvement (IHSI) and/or the installation of a hydrogen injection system may provide for a long-term solution to the problem. In the meantime, flawed pipes have been repaired with a weld overlay procedure to allow utilities the necessary time to plan and prepare for a permanent resolution. This paper describes the evolution of weld overlay repair designs and suggests that if the obstacle of inspectability can be overcome, it may be possible to consider the weld overlays themselves as the long-term solution.