There is an abundance of references to boiler design and failures. First you should peruse the library of the National Board of Boilers and Pressure Vessels on the subject matter as they write extensive articles via their National Board Bulletins on related failures. Your research may have to go back several decades. Since you are a "newbee" in this field, the Power magazine is a subscription that you need to get and of importance is their magazine titled Steam Generation which give you a better understanding about the design of steam generators of past and present. If you are lucky enough, you should also try to get a copy of the former NorthEast Utilities Service maintenance package that details every aspects of boilers design and their related maintenanced; I don't know the current company's name, however, their headquarters is ,I believe, in Meriden, Ct.. Another great area of research are the insurance companies that provide boilers and Pressure vessels insurance coverage such as Hartford Steam Boilers; who would know better about boiler failures.