CHANGES IN SECTION XI EXAMINATION REQUIREMENTS 1989 EDITION TO 1996 ADDENDA

摘要

Over the years, Nuclear Power Plant owners have expended significant cost and man-rem exposure performing Code required examinations that have shown very few service-induced flaws. Additionally, confusion over Code language has caused many owners to misinterpret the Code, resulting in both overly conservative and non-conservative conclusions regarding examination requirements. One task of the Working Group on Inspection of Systems and Components (WGISC) is to evaluate cumulative nuclear component performance history and, where warranted, revise examination requirements to correspond to this historic performance level. Such revisions are considered to be "technical" Code Changes. Another task of the WGISC is to monitor inquiries regarding inspection requirements and revise the Code to eliminate language that could be confusing to the user. Revisions such as this are considered to be Code "maintenance" changes. Although there have been many maintenance changes since the 1989 Edition that make the Code much more understandable to the end user, such changes are not addressed here. The purpose of this paper is to highlight the more significant changes in inspection requirements that have occurred from the 1989 Edition of Section XI to the currently approved 1995 Edition through 1996 addenda. These technical changes typically result in significant cost or man-rem savings and/or increases in plant safety.