Monitoring coolant gas composition at TBM-like operating conditions

When helium cooled test blanket modules (TBM) are tested in ITER, the gas composition has to be monitored constantly. In this paper, we present results of measurements performed with a mass spectrometer, while Helium Loop Karlsruhe (HELOKA) facility was operated at TBM-like conditions (300 °C – 400 and 8 MPa). An accuracy 1 ppmv or lower is reachable well calibrated instrument. Measurements reproducible can automated. The showed that loop filling procedures ensure stream HELOKA low level impurities range 0.02 % even after long time operation.