This process results in 216 data records that document crack (both partial and full) and leak events associated with non-pipe primary coolant system components. This dataset can be considered complete for U. S. NPP operation from 1990 through 2002, inclusive, in as much as the LER reporting requirements (Attachment A) can be relied upon to generate complete reporting. Additionally, the dataset does include a limited amount of data from outside this time frame and from non-U. S. plants. Nevertheless, the dataset can be considered to be internally consistent, that is, the various components, failures and degradation

mechanisms are believed to be represented equally such that relative ratios (if not the absolute frequencies) can be assumed to be reasonably accurate. Several of the database records represent multiple cases of degradation or failure. Attachment C includes a sample of multiple event records, including a discussion on how to estimate flaw frequencies from the observed events as recorded in the database.

The figure below (Forms view of the database) identifies the various fields maintained by the database. For additional detail on those records based on LERs, the LER hyperlink can be clicked to retrieve the full LER (internet access is require for this).