Ozone, predicted to be an important intermediate species in Tz oxidation, was monitored in situ by UV absorption spectroscopy for 0.01-1.0 mol% Tz in Oz (1 atm, 298 K). These are the first measurements of a tritium oxidation reaction intermediate. The experimental results were compared with the predictions of our comprehensive model of tritium oxidation. The experimentally determined temporal variation in ozone concentration is qualitatively ...