[en] The Nuclear Regulatory Commission's integrated containment analysis code, CONTAIN, has been adapted to perform confinement analysis of the N-Reactor. In the first phase of adaptation, flow path logic updates were generated and included in the CONTAIN code in order to handle the complex venting scheme of the confinement system. The modified code was applied to a hydraulic analysis of a hypothetical accident sequence, and the results were compared to previous calculations that had been completed with the HECTR code. In the second phase, fission product transport was invoked in the CONTAIN input deck to allow tracking of noble gas isotopes, molecular iodine isotopes, and inert aerosols. The interaction of sprays with suspended fission products was compared to earlier results given in the N-Reactor Updated Safety Analysis report. Finally, recommendations were given for new model development that would be beneficial to future analysis of the N-Reactor using CONTAIN. 8 refs., 32 figs., 8 tabs