I wonder where the steam generators were built. Since Westinghouse closed the Pensacola plant, I think steam generators are sourced from overseas. My guess is they’ve been finding leaks and plugging tubes at a rate that is unusual.
By now the utility should know to monitor and maintain the correct water chemistry.
http://finance.yahoo.com/news/heavy-tube-wear-mystery-calif-225007321.html
The short answer is: “The steam generators were manufactured by Japan-based Mitsubishi Heavy Industries, according to company officials.”
Yep... Sacrificial zincs, salt water, electricity etc...