4.1 The ENDF/B library in the United States and similar libraries elsewhere, such as JEF (9), JENDL (7), and BROND (8), provide a compilation of neutron cross section and other nuclear data for use by the nuclear community. The availability of these excellent and consistent evaluations makes possible standardized usage, thereby allowing easy referencing and intercomparisons of calculations. However, as the first ENDF/B files were developed it became apparent that they were not adequate for all applications. This need resulted in the development of the ENDF/B Dosimetry File (5, 10), consisting of activation cross sections important for dosimetry applications. This file was made available worldwide. Later, other“ Special Purpose” files were introduced (23). In the ENDF/B-VI compilation (41), dosimetry files were identified, but they no longer appeared as separate evaluation files. The ENDF/V-VII compilation (37) removed most of the covariance files used by the dosimetry community. It kept the covariance files for the “standard cross sections” in a special sub-library, but the covariance data in this sub-library is only provided over the energy range in which each reaction is considered to be a “standard”, and does not include the full energy range required for LWR PVS dosimetry applications.
4.2 Another file of evaluated neutron cross section data has been established by the International Atomic Energy Agency (IAEA) for reactor dosimetry applications. This file, the International Reactor Dosimetry File (IRDF-2002) (6) , draws upon the ENDF/B files and supplements these evaluations with a set of reactions evaluated by groups often outside of the United States. Some of the IRDF-2002 supplemental reactions represent material evaluations that are currently being examined by the CSEWG. The supplemental IRDF-2002 evaluations only include the specific reactions of interest to the dosimetry community and not a full material evaluation. The ENDF community requires a complete evaluation before including it in the main ENDF/B evaluated library.
4.3 The application to LWR surveillance dosimetry may introduce new data needs that can best be satisfied by the creation of a dedicated cross section file. This file shall be in a form designed for easy application by users (minimal processing). The file shall consist of the following types of information or indicate the sources of the following type of data that should be used to supplement the file contents: