This paper presents the measurement system for continuous monitoring of radioactive gases activity at the exhaust stack of RA reactor ventilation system. Industrial PC computer acquires analog signals from two flow ionization chambers and two analog signals from BPH device. Flow ionization chambers and BPH device can be remotely tested from control room. The computer program for data analyzes and presentation is written in graphical programming language LabVIEW 8.5 and enables monitoring of measurement data in real time. Measurement data can be seen over local computer network, Internet and mobile devices using standard web browsers.