High-sensitivity quadrupole mass spectometry system for the determination of hydrogen in irradiated materials

High levels of helium and hydrogen are generated in metals in fusion reacto rs, and fusion simulations in mixed-spectrum fission reactors, spallation n eutron sources, and high-energy charged particle environments. Although hyd rogen generation rates are generally higher than those of helium, hydrogen is thought to quickly diffuse out of metals, especially at elevated tempera tures. There appear to be some conditions, however, where significant hydro gen retention can occur. To assess this potential, a high-sensitivity analy sis system has been developed for the measurement of hydrogen in small samp les of irradiated materials. The system is based on a low-volume extraction furnace in combination with a quadrupole mass spectrometer, and has a dete ction limit of similar to1 appm for steel. Hydrogen levels have been measur ed in high-energy proton-irradiated tungsten and Inconel 718, in iron-based alloys and vanadium alloys from fusion materials programs, and in stainles s steels and pure metals irradiated in light water reactors. Details of the system and typical results are presented. (C) 2000 Elsevier Science B.V. A ll rights reserved.