Study on the passive refrigeration for main control room of nuclear power plant in power outage accident

High-pressure air with room temperature can be used for refrigeration through isentropic expansion or isenthalpic throttling process with no power supplying, which can also meet the demands of oxygen supplying for operators in the insulated situation. Two passive cooling strategies for high-pressure air are proposed: one is throttling refrigeration, and the other is expansion refrigeration, which can provide an effective method to ensure the safety of operators in main control room when an emergency occurs in nuclear power plant. Comparisons between the two passive cooling strategies are done by theoretical and experimental methods, and the cooling effects for both strategies are analyzed. The results show that the passive cooling strategy of isentropic expansion can meet the both requirements of cooling and clean air supplying for the main control room when emergencies occur in nuclear plants, with the minimum cooling capacity of 3000 W.