[en] A ABBN-type 26 group cross section library consisting of 34 nuclides for fast reactor calculations is presented in this report. The nuclides are H-1, Be-9, B-10, B-11, C-12, O-16, Na-23, Mg, Al-27, Ti, Si, V, Cr, Mn-55, Fe, Ni, Cu, Ga, Nb-93, Mo, Sn, Pb, Th-232, U-233, U-234, U-235, U-236, U-238, Pu-238, Pu-239, Pu-240, Pu-241, Pu-242 and Am-241. Tabulated data are infinitely dilute cross sections, inelastic transfer matrices, self-shielding factors, and fission source data for uranium and plutonium system. The multigroup constants were generated by ETOX-K4 code using ENDF/B-IV and ENDL-78 for basic nuclear data. This group constant set was used in the calculation of several CSEWG benchmark problems to test the applicability on fast reactor calculations. (Author)