Experimental determination of air inleakage to pressurized main control room caused by personnel entering

When persons open the door and enter the main control room of a nuclear power plant, toxic or radiological contaminants in the surrounding area can potentially be carried into the room, which will damage the personnel safety. However, an assumed amount of inleakage is adopted in habitability analysis, without further verification. Therefore, this paper aims to investigate the actual inleakage caused by a person entering the control room. In order to determine the exact inleakage volume, full-scale experiments with a real person were performed in an inner-outer rooms model. The air in the outer room (the unfiltered air) was marked with tracer gas, so that the inleakage volume can be easily distinguished. The results showed a linear relationship between the inleakage and the door swing time (from 3 s to 8 s), from which the inleakage volume of 0.628-1.023 m3 was estimated for a single entry. We attributed the total inleakage to two parts: door pumping volume and person additional volume. The pumping volume was estimated at 0.65 m3 with little variation, while the person additional volume was affected by swing time markedly. These inleakage data would be important information for the evaluation of control room habitability.