Additional Information

DOESTD107393

In-service Inspection Requirements. Discussion of in-service inspection (ISI) and in-service

testing (IST) as specified by Section XI of the ASME Code. These requirements should be

summarized and the procedures that implement the specific ISI and IST requirements should

be listed or referenced.

Testing and Testability Requirements. Describe testing requirements established by design

engineering. Describe unique system testing requirements that resulted in special system

design features.

Material Condition and Aging Management. Describe additional testing or operational

measures specified by the MCA program. May include both those measures specified for life

extension and other measures for general aging management.

ADDITIONAL INFORMATION

In addition to sections described above, the following provides information that may be useful in

understanding existing configuration and evaluating proposed changes. The users and uses of the

facility DISs may influence the selection and content of these sections. These sections are optional.

Change History. Description of the design change history. The change history section is

either a narrative or a listing of changes to the system since facility startup with an

explanation of the need for each change. This information serves several purposes: (1)

provides a ready source of rationale for past changes to systems, structure, and

components; (2) aids the review process to ensure design basis and requirements are

updated and design continuity is maintained; and (3) assists the process of root cause

determination of operational problems.

Design Margin. Design margin is the conservatism between the specified design requirement

and the minimum requirement that could be developed from the design basis. This section

could be presented as a table that shows the specified design requirement compared to the

possible design requirement if margin was removed. It could be invaluable when evaluating

operability concerns. In addition, this section could be a key input to the preparation of USQ

safety reviews, since this information addresses the impact of changes on the margin of safety.

However, this can be a difficult section to develop in that system sensitivity analyses, which

would enable identifying component margins, may not have been performed. It is important

not to identify margin that was added for calculational uncertainty as usable design margin.

Identifying and documenting margins when specific design basis information is being

developed, or as subsequent analyses are performed, could be a valuable reference.

Summary of Critical Calculations. Summaries of the most important system calculations could

be provided along with basic assumptions, calculational methods, relationship to other

calculations, and general conclusions of calculations.

Postulated Failures. Description of failure modes considered in the system design. It could

include passive failures, such as pipe breaks, and active failures, such as failure of a valve to

close or pump to start on demand. A discussion of the impacts of a postulated support

system failure, (such as a valve repositioning on a loss of instrument air) could also be

included. Facility events may lead to special tests or analyses that can be used as inputs to

this section.

Response to Transients. The specific response of the system could be described for facility

transients and accidents.

II-D-5