Abstract: ORIGEN-2 is a versatile point depletion and decay computer code. Its functions, major charactaristics, and theoreticahmodels are briefly introduced in here. The transplantation of the code on IBM 4300 series computers and its augmentation of output photon data and application in calculating gamma-ray spectra of fission products are described.

Key words: reactor code, fission products, gamm-spectrum, fuel cycle