Investigation of Inlet Blockage in the Central Subassembly of a Sodium-Cooled Fast Reactor

An investigation of inlet blockage in the central subassembly (SA) of a medium-sized sodium-cooled fast reactor (SFR) is carried out. To analyze the accident scenario, a sodium boiling model is developed based on two-fluid approach. The model is added to the thermal model based on the single-pin assumption developed in the previous study. The developed model is validated with CABRI BI1 loss of flow experimental data. Having established the validity of the model, a detailed analysis of inlet blockage in the central SA of a medium-sized SFR is carried out. The model is able to predict the accident detection time by temperature monitoring thermocouple located at the SA outlet. Boiling front evolution, temperature evolution of the core components, dryout time, and clad melting time are predicted. A parametric study on the effect of growth of blockage at the SA inlet on time of detection and boiling is carried out.