In an effort to minimize the accidental concentration of nitrogen oxides ( NOx ) in the exhaust emission process of nuclear facilities, an implementation scheme of arranging the exhaust pipe outlet of NOx in the exhaust chimney is proposed. The flow and diffusion process of NOx in the exhaust chimney during the loading process is studied by numerical simulation methods, and the influence of the emission height and layout orientation of the ex-haust pipe on the flow and diffusion of NOx is discussed. The results show that there is a NOx concentration area with a clockwise spiral rise in the chimney, and NOx is discharged from the chimney with a similar mass concentra-tion distribution cloud pattern when the height of the chimney is above 70 m. When the exhaust pipe is located in the center of the chimney, the local maximum mass concentration of NOx and the mass concentration variation coef-ficient at the chimney outlet increase with the increase of the exhaust outlet height (10-60 m) . However, the lo-cal maximum mass concentration of NOx and the average mass concentration of the cross section at the personnel working area decrease significantly with the increase of the exhaust outlet height (10-30 m). When NOx is dis-charged at a low level, the optimal arrangement is an exhaust emission height of 20 m and +90° orientation. When NOx is emitted at a higher position, the exhaust gas outlet should be arranged in the center of the chimney as far as possible.
维普
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