Thermal-Hydraulic Performance of a 2 MW_t Sodium-Heated, Forced Recirculation Steam Generator Model

The results of LMFBR (Liquid Metal Fast Breeder Reactor) steam generator model tests conducted in a 2 MW_t sodium-heated test facility at prototypical Breeder Reactor Demonstration Plant conditions are presented. This includes heat transfer performance data and a sodium-side heat transfer correlation for a seven-tube bayonet tube forced recirculation evaporator with identical tube geometry to a proposed LMFBR Demonstration Plant evaporator. The departure from nucleate boiling characteristic of the bayonet tubes employing swirl flow generators and the steam-side heat transfer coefficients in the transition boiling regime were measured. The steam-side boiling stability characteristics of the evaporator were evaluated and a summary of the results are presented. The results also include heat transfer performance data for a helical coil superheater containing two active tubes and one inactive tube. Sodium temperature distribution data for the evaporator measured at various load conditions indicating steep axial temperature gradients in the sodium inlet plenum region are presented along with sodium temperature distribution data for the superheater. Finally, sodium-side instability data associated with series operation of the models, both containing cover gas spaces, are presented along with sodium temperature fluctuation data measured in the inlet plenum of the evaporator.