Gram quantities of titania (TiO 2) nanotubes, with a typical outside diameter about 9 nm, wall thickness of about 2.5 nm, and length of about 600 nm, were synthesized from anatase nanopowder and micropowder using the hydrothermal method. The crystallization, structure, and phase stability of the nanotubes at high temperatures were studied. A morphology change from nanotube to nanowire was observed at 650 • C. The as-prepared nanotubes were usually contaminated with sodium impurities and were poorly crystallized, but under optimized synthesis conditions the impurity phase was completely removed, resulting in highly crystallized nanotubes. The volume filling fraction of the autoclave as well as the concentration of the acid treatment were found to be particularly important for controlling the purity and crystallinity of the resulting nanotubes. The various TiO 2-derived nanotube phases (sodium titanate and hydrogen titanate) reported previously by different groups were also observed under different synthesis conditions, resolving the contradiction among the previous results.

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The separation and recovery of radiostrontium from simulated alkaline reprocessing waste solution has been studied using Amberlite IRC-718, a chelating resin containing iminodiacetic acid groups. The breakthrough behavior of strontium has been determined by conducting an extended column run. The column loading performance has been correlated with batch equilibration results. Efficient elution of loaded strontium has been achieved using dilute nitric acid. Satisfactory column performance has been demonstrated in repeated loadingelution-regeneration cycles. Finally, the characteristics of used resin have been determined to ascertain its efficacy for further use.

A radiation-resistant nuclear battery combining betavoltaic and photovoltaic techniques was demonstrated using Ce-doped Gd3Ga3Al2O12 single-crystal scintillator. The present device comprising 1 mm thick Ce-doped GGAG single-crystal scintillator and Si-based p–i–n diode produced an electric power output of 48 nW with a short-circuit current of 490 nA and an open-circuit voltage of 0.18 V using a 3 mCi 106Ru source. Long-term radiation stability test carried out for more than 4000 h revealed that there was no significant reduction in the output of beta-photovoltaic device (with scintillator), whereas there was 68% reduction in the output power for the betavoltaic device (without scintillator). The electron beam irradiation of 1 mm thick Ce-doped GGAG scintillator up to a dose level of 5 MGy using 10 MeV electron beam indicated a power degradation by 4% suggesting a reasonably long battery life (∼15 years) with 90Sr-90Y source.