AbstractThe processing code SYMPAL is used to perform the necessary data treatment involved in the creation of a version of the European Activation File (EAF). The entire process is handled by different modules of the code in a sequential and orderly manner. Two major data bases are accessed and merged so as to create a new library level. The Master Data File (MDF) contains the original cross-section data extracted, unmodified but reformatted, from numerous sources. The Master Parameter File (MPF) contains a compilation of all physical information necessary to renormalise, split and internally validate any particular type of cross-section. The combination of the two Master files generates a new activation file in a pointwise and various groupwise formats. An uncertainty file, reporting information and validation plots, is also produced.