Technical feasibility of integrating a modified power conversion unit into a non-nuclear microreactor testbed

This work analyzes the feasibility of integrating a modified commercial Capstone C30 microturbine unit into a non-nuclear testbed developed for performance evaluation of microreactor design concepts. Testing will be conducted to provide detailed reactor core and heat removal section thermal hydraulic performance data for prototypical geometries and operating conditions and demonstrate integration with relevant power conversion units. The modified C30 power conversion unit (PCU) uses external electrical heating, rather than fossil fuel combustion, to provide a maximum power output of ~30 kWe in a closed Brayton cycle (CBC) loop using nitrogen as the working fluid. A 75 kWt electrically heated test article was evaluated as the heat source to provide a turbine inlet temperature of 600°C to the modified C30 PCU. The operation of a test article supplying a maximum thermal power of 250 kWt was also considered. The analyses performed here indicate that the CBC PCU will be capable of operating over a range of steady state and transient conditions to evaluate test article heat transfer performance in representative operational scenarios. Normal, off-design operation and dynamic stability of the PCU are analyzed, and a proposed set of tests of the power control schemes and heat source-PCU coupling are outlined. This study supports the timely development of microreactors intended for deployment by the end of this decade.