The Very High Temperature Gas-Cooled Reactor (VHTR) is one of the six Gen IV reactor designs, which will generate electricity and high temperature heat for industrial applications.
The design of the VHTR includes a new passive safety system that is designed to remove heat and maintain temperatures of steel and concrete structures within safety limits, during normal operations and accident scenarios. The Reactor Cavity Cooling System (RCCS) provides an entirely ex-vessel means to reject decay heat to the environment without the need for pumps, diesel generator, or human intervention.
We are actively contributing to the design and optimization of this new safety system, by conducting extensive experimental and computational research aimed to gain understanding of the physical phenomena involved, and verifying the correct functionality of the system. We have designed, constructed, and operated a 1/23-scale water-cooled RCCS facility to investigate the flow behavior of the water, to study the complex heat transfer mechanisms in the reactor cavity, contributing to the overall design validation and optimization of this device. Experimental data produced are compared with simulation results, contributing to the validation of system level computer codes, and Computational Fluid Dynamics (CFD) codes.
The facility features a nine-riser panel, electric heaters, and transparent sections (manifolds, risers’ inlet/outlets, water tank) to perform flow visualization and measurements, and a large number of thermocouples to measure the temperature of coolant and cavity walls.
Particle-Image Velocimetry (PIV), Laser-Doppler Velocimetry (LDV), and Distributed Temperature Sensor (DTS) measurement techniques are being applied.
The project is sponsored by the Nuclear Energy University Program (NEUP) – DE-NE0008552, in collaboration with:
- University of Wisconsin – Madison
- Argonne National LAboratory
- Ultra-Safe Nuclear Company