Confined space can be defined as closed or semi-closed equipments, facilities and places which potentially have poor ventilation, poisonous and hazardous gases or poor oxygen. Confined space has complex working environment and more hazardous factors which makes safety accidents occurred frequently. Modularized Construction, as the typical feature of AP1000 nuclear project construction, shortens the construction schedule but increases safety risk, since there is more confined space and cross work, especially in the Containment building after the setting of CVTH.
This thesis analyses the confined space construction feature of the containment building and emphasizes the necessity of ventilation and fume control. Some ventilation methods have been taken on site which has effectively reduced the construction risk inside containment buildings. Therefore, this thesis has practical value for the consequent AP1000 project construction.