The original design and construction of most operating nuclear production facilities today predates the discipline of configuration management. Consequently, these facilities found themselves, at some point in their history, without adequate mechanisms to ensure reasonable correlation between regulatory requirements, facility documentation, and the physical configuration of the facility itself. Without confidence in the relationship between design information and the plant, many facilities were unable to maintain a reasonable level of trust with the public in their geographic area.

In the United States, many plants experienced this dilemma when confronted with the task of replacing components that had failed and discovering that the original vendors were no longer in existence, or no longer manufactured a suitable 'like-for-like' replacement. In the course of identifying the original design requirements for these components, it quickly became apparent that a mechanism was needed to connect plant structures, systems, and components (SSCs) to the original design requirements. Since this mechanism had not been incorporated within the original design and construction of the facilities, there was no clear methodology for the reconstitution of what we now call the 'design bases'.

A variety of methodologies and mechanisms were used to reconstitute design bases with varying degrees of success. One critical limiting factor that quickly emerged was the recognition that reconstitution of the design bases for an operating facility could be prohibitively expensive. This factor alone would be significant enough to specify the scope of design bases recovery efforts and contributed substantially to the permanent closure of one US facility (Zimmer, Ohio, USA, 1984) prior to commercial operation but after loading fuel.

Attempts were made to bring clarity and efficiency to the design bases management effort. Through the United States Nuclear Regulatory Commission (USNRC), and the Nuclear Energy Institute (NEI), documentation and guidance were provided in what ultimately became NEI 97-04, "Guidance and Examples for Identifying 10 CFR 50.2 Design Bases". This document, as well as others developed through efforts by the Institute of Nuclear Power Operations (INPO) and the International Atomic Energy Agency (IAEA) provided an reasonable basis for implementing configuration management as we understood it then and back-fitting design bases management to existing plants.

But that was then...