[en] An adequate dissipation of after-heat via natural circulation can be demonstrated by dynamic simulation of the entire LMFBR plant. Models needed to accomplish this task are briefly described in the paper. The resulting computer code, SSC-L, is then applied to simulate the response of the Clinch River Breeder Reactor Plant for a loss-of-electric power transient. Entire simulation is performed for 1800 seconds of the transient time. The decay heat removal via natural circulation is shown. The effect of internal flow redistribution in the reactor core is also demonstrated