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  • Author or Editor: Y. Sakuma x
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Abstract  

An apparatus was designed and constructed for investigation of the tritium release rate from neutron-irradiated materials for fusion reactors. The design principles, as well as safe handling of tritium and complete trapping of tritium components released, are described and the tritium release rates obtained with this apparatus are discussed for sintered lithium fluoride pellets.

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Abstract  

Liquid scintillation counting is the most popular method for tritium measurement, however, it takes much time and a lot of doing to distill off the impurities before mixing the sample water and liquid scintillation cocktail. We have investigated the possibility of an alternative method to the distillation. We have found out that the filtration can be an alternative to distillation for the environmental water samples before electrolytic enrichment.

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Abstract  

A tritium separation from heavy water by electrolysis using a solid polymer electrode layer was specified. The cathode was made of stainless steel or nickel. The electrolysis was performed for 1 hour at 5, 10, 20, and 30 °C. Using a palladium catalyst, generated hydrogen and oxygen gases were recombined, which was collected with a cold trap. The activities of the samples were measured by a liquid scintillation counter. The apparent tritium separation factors of the heavy and light water at 20 °C were 2 and 12, respectively.

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Abstract  

The dynamics of redox related elements (Fe, Co, Zn, and Se) were studied using instrumental neutron activation analysis as a function of rat age in the range of 4 to 16 weeks. Activity levels of glutathione peroxidase (GSH-Px), thiobarbituric acid reactive substance (TBARS) were assayed, and hydrogen peroxide (H2O2) concentrations were measured for the same liver homogenates using an X-band ESR spectrometer. The oxidative stress, the aging effect, and the mineral valance are discussed.

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Abstract  

n this study, the application for monitoring atmospheric tritium at the site of nuclear fusion facility is presented. Construction and examination of the tritium sampler and its arrangement at the site are mainly discussed. Atmospheric tritium concentrations at Toki site were determined in the sampling period from September 2000 to June 2001. Although the data for HTO were low because of their low specific activity (0.62 Bq/l), our average HT and CH3T data were 9.1 and 3.3 mBq/m3, respectively, and systematically lower than the previously reported values at the same site, even if the considerable decay correction was carried out. Suitable monitoring points are discussed by considering the local meteorological features at the Toki site. Since the wind conditions at this site were governed by diurnal and nocturnal wind blowing to the contrary directions, it is concluded that the monitoring points should be placed at the site boundary of downwind direction of these winds. Considering that the expected levels of effluent tritium in the D-D experiment at the National Institute for Fusion Science are competitive with those in the environment, the detailed variations of the environmental tritium should be comprehended to detect minute amounts of the artificial tritium.

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