The release of crude tritium gas from neutron-irradiated LiAl alloy, and the following purification and the trapping of the gas have been preliminary studied to obtain information necessary for the development of tritium technology. The percentages of the fractions of H2 (T) and H2O (T) occupying about 99% among gaseous species (T) released were largely influenced by pre-irradiation treatment of the alloy and especially by heating temperature of the irradiated alloy. In the isothermal heating at 850°C, about 95% of tritium was released as H2 (T) . For obtaining all of tritium as H2 (T), the fraction of H2O (T) was successfully converted to H2 (T) with U turnings at 800°C. Hydrogen (T) could be effectively trapped in a pulverized U Better at room temperature.
A convenient method of77Kr production has been developed for its routine medical use in cerebral blood flow measurement. An aqueous solution of NaBr (40 wt%) was used as the target and77Kr produced by the79Br (p, 3n) 77Kr reaction was rapidly recovered from the target under a He stream. The optimal target thickness was determined to be 5-6 mm by investigating radionuclidic purity and proton current effect on the yield. About 740 MBq (20 mCi) of77Kr with a radionuclidic purity of 92% was obtained within 5 min after a 5μA-20 min irradiation. The present method has been demonstrated to be suitable for routine77Kr production.