Experimental Study of Scram Transients in Generalized Liquid-Metal Fast Breeder Reactor Outlet Plenums

An experimental study was made of the transient behavior of the coolant in a generalized outlet plenum after a scram in a liquid-metal fast breeder reactor. Different conditions of fluid flow rate and temperature and plenum geometry were used for a three-exit loop-type reactor system. Water was used to simulate the coolant, and a small-scale model was used to simulate the various generalized plenum configurations. Thermocouples monitored the temperatures at 48 locations within the outlet plenum. The thermohydraulic behavior within the plenum has been studied in detail; analysis of this behavior is described as having three consecutive discrete stages. Correlations found in the literature accurately predict the height of the negatively buoyant plume. New correlations have been obtained.