One major accident of interest in the High Temperature Gas-Cooled Reactors is the Pressurized Conduction Cooldown (PCC) scenario. The PCC scenario results in a loss of forced convection to the core, while the loop stays pressurized since there is no breach in the boundary. The coolant flows through the core driven by buoyancy forces. Experimental data is needed to validate the performances of CFD codes.
An experimental facility representing the core and upper plenum of a HTGR has been designed and constructed to perform natural circulation experiments. The test sections include multiple vertical heated channels representing the coolant flow paths within a typical prismatic core design. Channels are independently heated.
Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) techniques are being applied.