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Influence of ThO2 on the photocatalytic activity of TiO2

100%

Kralchevska R., Milanova M., Kovacheva P., Kolev J., Avdeev G., Todorovsky D.

Open Chemistry

2011

vol. 9

issue 6

1027-1038

Microcomposites consisting of TiO2 (or Ce-doped TiO2) and ThO2 (0.5–2% of the TiO2 mass) are produced by sol-gel synthesis of TiO2 in presence of ThO2. X-ray diffraction study reveals the effects of ThO2 (compared to the ThO2-free TiO2, obtained by the same method) on the anatase interplanar distances, crystallites size and phase composition. The photocatalytic tests in presence of the composites under UV irradiation reveal an increase of the Malachite Green degradation rate constant. The effect depends on the Th relative content, temperature of annealing of the catalyst and addition of other doping agent. The highest photocatalytic activity is observed for TiO2 obtained at 550°C and containing 1% ThO2. The composite exhibits activity in dark, also. The presence of Ce4+ ions is not an obligatory requirement for the realization of the ThO2 effect. The reported results suggest that the radioactivity of the Th and/or its decay products is one of the main factors responsible for the increased photocatalytic activity of TiO2. [...]

Burn-up calculation of different thorium-based fuel matrixes in a thermal research reactor using MCNPX 2.6 code

86%

Gholamzadeh Z., Hossein Feghhi S. A., Soltani L., Rezazadeh M., Tenreiro C., Joharifard M.

Nukleonika

2014

vol. 59

issue 4

129-136

Decrease of the economically accessible uranium resources and the inherent proliferation resistance of thorium fuel motivate its application in nuclear power systems. Estimation of the nuclear reactor’s neutronic parameters during different operational situations is of key importance for the safe operation of nuclear reactors. In the present research, thorium oxide fuel burn-up calculations for a demonstrative model of a heavy water- -cooled reactor have been performed using MCNPX 2.6 code. Neutronic parameters for three different thorium fuel matrices loaded separately in the modelled thermal core have been investigated. 233U, 235U and 239Pu isotopes have been used as fissile element in the thorium oxide fuel, separately. Burn-up of three different fuels has been calculated at 1 MW constant power. 135X and 149Sm concentration variations have been studied in the modelled core during 165 days burn-up. Burn-up of thorium oxide enriched with 233U resulted in the least 149Sm and 135Xe productions and net fissile production of 233U after 165 days. The negative fuel, coolant and void reactivity of the used fuel assures safe operation of the modelled thermal core containing (233U-Th) O2 matrix. Furthermore, utilisation of thorium breeder fuel demonstrates several advantages, such as good neutronic economy, 233U production and less production of long-lived α emitter high radiotoxic wastes in biological internal exposure point of view

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1 Joharifard M.

1 Kolev J.

1 Kovacheva P.

1 Kralchevska R.

1 Milanova M.

1 Rezazadeh M.

1 Soltani L.

1 Tenreiro C.

1 Todorovsky D.

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Influence of ThO2 on the photocatalytic activity of TiO2

Burn-up calculation of different thorium-based fuel matrixes in a thermal research reactor using MCNPX 2.6 code