[en] DELFIN code is a CDC 3600 version of the CINDER programme which calculates time dependent nuclide number densities. 0utput obtained shows nuclide concentrations for a sepies of time intervals where neutron flux, absorption and fission rate are considered to be constant. Variations in these parameters are indorporated via the use of finite time increments. Changes in comparison to the original programme are concerned with improvements of the input and output, double precision, flexibility of use accounting for differences in released energy per fission for each nuclide. (author)