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In Chapter 26, Owen F. Hedden provides an overview of the stipulations of Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. A chronological overview of the development of Section XI is presented, from its inception in 1968 up to the 2004 Edition including 2006 Addenda. The chapter traces the development, Edition-by-Edition, of important elements of the Code, including the philosophy behind many of the revisions. Emphasis is placed on the 1989 through 2004 Editions, for they apply to the majority of plants in the United States and elsewhere. Through an extensive tabulation of Code Interpretations, this chapter also attempts to give the Code User some insight into clarification of many Section XI requirements.
In the current revisions of Section XI, feedback from operating plants has resulted in new requirements to address stress corrosion cracking mechanisms, weld overlay piping repair techniques, and a program for risk-informed piping inspections.
Owen notes that subsequent chapters of this book address the major areas of Section XI: in-service inspection examination and test programs, repairs and replacements, acceptance and evaluation criteria, containment programs, and fatigue crack growth. Nondestructive examination (NDE) is addressed in this chapter, as its requirements evolve. Owen mentions that Section XI initially had only 24 pages in 1970 but that it now has over 700 pages. Although originally it covered only light-water reactor Class 1 components and piping, now it includes Class 2 and Class 3 systems, metal and concrete containment, and liquid metalcooled reactor plants. With his association with Section XI Code Committee activities since their beginning, Owen is in a good posi-tion to comment on important areas that should not be overlooked as well as unimportant areas that should not distract attention.
