Experimental study of air leakage from cracks in reinforced concrete walls

Nuclear power plant buildings must be air tight even if shaken by an earthquake of the strongest level (S1 level) even after cooling materials have been released within the structure.This study was intended to research air leakage through shear cracks in walls. Tests were done on a three-dimensional one-tenth-scale specimen based on a part of a prototype boiling-water reactor nuclear power plant. During the tests, the specimen was subjected to a lateral load, simulating those caused by an earthquake. The amount of air passing through cracks in the specimen was measured at every level of lateral loading, while the load was being applied and also after it had been removed.It was found that only very small amounts of air passed through cracks. Because nuclear power plant buildings have very thick walls, the air-tightness of these buildings appears to be secure even after an accidental loss of cooling materials followed by a severe earthquake. (orig.)