DESCRIPTION OF NON-PIPING DATABASE

H. 1 Background

The non-piping database has been compiled with the intention that it will serve as one source of information supporting the development of estimates of LOCA frequencies attributable to non-pipe components. The data has been obtained from two primary sources. First, a search of LERs was made to identify those instances where failures[17] of non-pipe components of the primary reactor coolant pressure boundary were reported to the NRC. The second source of information is data that has been incidentally collected on non-pipe components during the development and maintenance of the pipe-based OECD and SLAP databases. LER events compose the majority of the events in the database (see Attachment A of this appendix for a description of the LER reporting requirements).

The database is accessible in two formats, Table and Forms. The Table named “Failure Data” lists the data in a spreadsheet type of format where each line of the table contains one data record and each column contains the various fields that make-up the records. In the Forms format, only one record of the “Failure Data” is displayed at a time, but in a manner that allows all of the fields to be view at the same time. Both formats display the same data, only the presentation is different. Also, sorting and filtering of the data can be done in both views.

H. 2 Approach

A search of LERs was performed (see Attachment B for the specific search criteria) using the SCSS. This search returned 1,036 LERs. Each LER was reviewed and coded in the Non-Pipe database. The database structure is based on information generated during the elicitation meetings. In particular, the component, piece part, and degradation mechanism are all identified using the tables documented in the elicitation meeting notes. Other fields of the database were developed and defined as judged appropriate.

The initial screening of the 1,036 LERs to remove those that were judged to not be applicable reduced the total number to 213. As discussed in Attachment B, the data search simply looked for leak and crack events associated with primary coolant systems. This conservative search included LERs that identified potential and possible leak and crack events (e. g., a problem with ECCS such that the plant would not respond as designed to a loss of coolant accident. Screening out the potential failures resulted in a reduction to 213 records. A further 34 records were removed since they identified problems with pipes or seals. Then 37 records were added that had been collected previously during the development of the OECD and SLAP databases. This results in a current total of 216 records.