AbstractActivation data and inventory codes are a major input to much of the safety related work carried out on fusion devices. The inventory code recommended for European activation calculations is fispact-99; this requires a large amount of nuclear data, which is available in the European Activation File (EAF-99). The production of an EAF library uses new sources of data, both evaluated and calculated, differential measurements and integral data. In order to store, evaluate, and use all the various data sources an efficient software tool is required. Earlier versions of EAF have been produced using the tools sympal and safepaq, which enabled a large degree of automation as compared with the original construction ‘by hand’. However, these relied on the direct manipulation of the ENDF formatted text files using fortran-77. This is not an efficient approach, as editing of the text files is inconvenient and liable to errors. It was decided to use relational databases to store the data, with data extraction carried out by standard queries written in sql. Other objectives were the provision of a user-friendly graphical interface to allow data to be viewed and manipulated and a high level of QA by logging all data changes. These objectives have been realised by the safepaq-II application; this uses the ideas of the previous tools, but has been designed from scratch using new methods. Visual Basic is used to build the application running under Windows NT 4, which is linked to a series of access databases.