Leakage Measurements of the DR 3 Containment during Reactor Operation to Meet a Demand of Maximum 0,1% Leakage per 48 Hours

The ratio between the absolute temperature T and the partial pressure F of the atmospheric air in the hall is taken as a representative of the number of air moles present. A plot versus time gives the leak rate. The temperature is measured by means of an iron wire through the hall; the pressure is determined by projecting the mercury surface of a precision manometer onto a screen. The arrangements and the measurement equipment are described and the uncertainties of the results discussed. The experiences from six yearly tests have led to a method which is considered to be more convenient than that used previously, and yet sufficiently accurate to control the tightness of the DR 3 reactor building.