[en] In recognition of the pressing need for nuclear decay data in a variety of reactor-related applications, the scope of the Evaluated Nuclear Data Files (ENDF/B) was expanded to include such information. The initial reason for this expansion was to provide reliable data and a common data base to be used in computer codes developed to carry out summation calculations of the decay-heat source term in reactor cores. The ENDF/B-V fission product file was released in July 1980 and contains data for 877 nuclides. Forty-two of these are found in greater detail on the General Purpose file. Seven hundred and fifty isotopes contain decay data. One hundred and ninety-six contain cross section data for total, elastic, inelastic, and angular distributions in the energy range 10^-₅ eV to 20 MeV. This special fission product file is contained on 6 magnetic tapes, and is available from the National Nuclear Data Center (NNDC) at BNL