Process and apparatus for sampling the air of the containment of a nuclear power station

摘要

1. Process for monitoring the activity of the building air in nuclear installations, in particular the building air in containments of a nuclear power station, having the following features: a) a stream of supply air (A1) of the building air to be monitored is extracted via at least one bleed line (E1) from the containment (1) and transported up to a measurement section branch piece (4), b) at the measurement section branch point (4) a representative measurement air stream (A11), which is substantially smaller than the stream of supply air (A1), is branched off from the stream of supply air (A1) via at least one measurement line (M1) and supplied to a measurement section (5), c) the stream of supply air (A1) reduced by the measurement air stream (A11) is led via a feedback line (E2) departing from the measurement section branch point (4) to the containment (1) and/or - via a filter section - into the vent stack, d) the measurement air stream (A11) is extracted intermittently from the stream of supply air (A1) in the form of defined sample volumes by means of at least one bleed valve (3), and for this purpose the movable control member (3a) of a bleed valve (3) with one passage (3b) is brought into at least two operating positions (I, II), a supply air side (Z) being connected in the operating position I to an exhaust air side (A), and a purge fluid side (S) being connected in the operating position II to a measurement side (M) of the bleed valve (3), and the sample volume respectively contained in the control member passage (3b) of the bleed valve (3) being conveyed with the aid of the purge fluid into the measurement section (5).