What Is a Nitrogen Reactor? Principles, Design & Applications Answering the core question: What is a nitrogen reactor, and how does an inert nitrogen atmosphere protect sensitive and hazardous reactions? A nitrogen reactor is a vessel operated under a continuous or batch nitrogen blanket that displaces oxygen to below 50 ppm, eliminating combustion and oxidation risk. By holding the vapor-space oxygen concentration under 5 percent of the lower explosive limit (LEL), it