approach is typically the most expensive. This approach should be used only for
the most important missing design requirements.
Gathering and documenting information from the experience of knowledgeable
engineering and operations personnel. Their memory is a valuable (and
frequently undocumented) source of information, and that information could be
lost through attrition, transfers, retirement and death. Following recognition of
the need to identify design information, contractors should promptly initiate this
activity to prevent any further loss of knowledge.
Repeating the original design process to decide which design outputs or portions
of the equipment specifications are essential and which are optional. This
approach is a combination of the first two approaches. While it may not go as far
as reanalysis, it does carefully consider the likely design inputs, constraints,
analysis and calculations, and outputs. After reanalysis, this is the most
technically acceptable method.
Testing equipment to determine its current functionality and accepting the results
as design requirements after a technical evaluation by the engineering
organization. Testing might be the only practical method for showing that system
performance remains adequate.
When selecting the approach to be used, the contractor should consider
what information is already available,
the importance of the systems and components,
A combination of methods is often the most cost-effective approach. Throughout design
requirements regeneration, the design basis resulting from the regeneration efforts should
be documented. The regenerated requirements should be incorporated into the
configuration management database.
Additional guidance on design basis reconstitution for a complex nuclear facility, such as
a reactor, can be found in IAEA-TECDCO-1335, Configuration management in nuclear