The catalytic effect of geologic samples on the deuterium (tritium)-water exchange reaction as studied with a quadrupole mass filter

Abstract

Abstract Evidence of exchange reactions between tritium gas and water has been observed in gas sampled from the vicinity of nuclear detonations. The purpose of this investigation, using deuterium gas as a surrogate for tritium, is to determine the catalytic effects of typical underground materials on the exchange reactions between hydrogenic species and water as a function of temperature. The apparatus constructed for these experiments consists of a constant pressure gas inlet system, a fused quartz tube containing the catalyst to be studied, and a quadrupole mass filter. The temperature range of the experiments was from ambient to 900 °C. The two gases, D2 and H2O, were mixed in the inlet system and then allowed to pass through the catalyst bed and into the mass filter through a glass leak. The results obtained can be summarized as follows: (1) the reaction is surface catalyzed; (2) equilibration takes place rapidly at room temperature and above, using platinum sponge as a catalyst; (3) for catalytic samples of tuff, alluvium, sandstone, and shale, the onset of observable reaction was between 400 to 500 °C with large amounts of products formed at 600 °C and above when the temperature was increased from ambient to 900 °C over a 6- to 8-hr period; and (4) deuterium and water appear to exchange at 200–300 °C in outgassed, partially decomposed limestone, presumably due to the catalytic activity of CaO and MgO.