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Joint Evaluated Fission (JEF) Library version 2.2

The JEF-2.2 version of the general purpose library was released in January 1992.

The library contains evaluations of neutron reaction data for 313 elements or isotopes from 1-H-1 to 99-Es-253 in the neutron energy range from 10E-5 eV to 20 MeV, in ENDF-6 format.

Superseded library

Please note that this is a superseded library that was approved for formal release but has been replaced with a newer official library version.


The complete set of data, including incident-neutron files for 472 nuclides, processed ACE format data in several temperatures from 293K to 1800K, processing inputs, TSL data and checking code outputs are available online here:


The NEA published summary documentation of the Joint Evaluated File version (JEF-2.2). The information contained in the file comprises neutron reaction data, radioactive decay data, fission yield data and thermal scattering law data. The report has been divided up in the following four parts:

  • Part one: origin of the data, modifications and improvements to the data before adopting them.
  • Part two: validation and testing for different nuclear applications.
  • Part three: validation of the JEF-2.2 data by means of cross-section adjustment studies.
  • Part four: proposed improvements to the JEF-2.2 file to meet the new challenges.


"The JEF-2.2 Nuclear Data Library", OECD, Nuclear Energy Agency, 92 - Issy-les-Moulineaux (France), ISBN 92-64-17686-1.