US scientists swap neutrons for LEDs to build glowing nuclear reactor

US scientists at Idaho National Laboratory (INL) have developed ViBRANT (Visual Benign Reactor as Analog for Nuclear Testing), a glowing surrogate nuclear reactor that uses thousands of LEDs to safely simulate the complex physics of a real reactor core without the hazards of uranium fuel or radiation. Controlled by the Microreactor Automated Control System (MACS), ViBRANT mimics heat and neutron feedback by varying LED intensity and color to represent changes in core temperature and reactivity. This innovative approach provides a visually intuitive, safe platform for studying reactor behavior, accessible even to non-specialists, and accelerates microreactor development by enabling rapid, hands-on experimentation without radiation risks. ViBRANT’s LED-driven core and MACS use the same electromechanical actuators planned for the MARVEL microreactor, a sodium-potassium cooled system designed to produce 85 kW of power for applications like data centers and desalination. The surrogate reactor allows engineers to simulate processes that take MARVEL a full day