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Pb and 
Be within the Kuji River watershed, JapanMatsunaga, Takeshi; Amano, Hikaru; Ueno, Takashi; Yanase, Nobuyuki; Kobayashi, Yoshii
Journal of Environmental Radioactivity, 26, p.3 - 17, 1995/00
Times Cited Count：16 Percentile：48.81(Environmental Sciences)no abstracts in English
; Yasu, Takami; Kawata, Tomio
PNC TN8410 91-325, 68 Pages, 1991/11
[Purpose] We confirmed modified (6000rpm type) centrifugal clarifier happened unstable vibration in the downward rotation on the condition of including undissolved residue after the clarification operation. This report describes the cause of unstable vibration and the measurement results of vibration characteristic after taking countermeasure for vibration decrease. [Method] It was considered that the cause of unstable vibration was four items in the following. (1)Unbalance between damping force of lower bearing damper and vibration force arisen by rotational bowl (2)Effect of feed condition (3)Effect of self-excited vibration on the free surface (4)Effect of frame strength that be set modified. This test is for take countermeasure to each item (1
3 item) in the upper items, and for quantitative measure of vibration characteristic (amplitude of rotational bowl and shaft) in the downward rotation on the condition of including undissolved residue after the clarification operation and for select best countermeasure, that is most effective to vibration damping, and does not arise the fall of clarification performance (capture efficiency), the increase of leak rate of feed solution and the fall of sludge washing performance. [Results] (1)We could not confirme vibration damping, compared with spring constant k=9 kgf/cm, damping constant c=20㎏f
s/cm and the former condition (k=600 kgf/cm, c=0.3 kgfs/cm). (2)In case of countermeasure that operate as balance ring by sludge cohering height on the inside wall of rotational bowl, we could confirm that the amplitude in the downward rotation is about 1/3, the leak rate of feed solution is about 1/6, compared with the case of feed solution 55㎜ in height from the lower plate of rotational bowl and the former condition (25mm in height from the lower plate of rotational bowl). (3)Compared with the case of setting the side baffle plate 150㎜ in height from the lower plate of rotational bowl for decreasing ...
retention with changing hydrophilicity of carbonate slurry, 1; Estimation of hydrophilicity on the surface of suspended solidKuwano, Ryo*; Nagaishi, Ryuji; Ito, Tatsuya
no journal, ,
The overflow event occurred in carbonate slurry wastes emitted from the 1F ALPS co-precipitation system is due to the highly viscous slurry retaining hydrogen molecules (H) formed by its radiolysis. Since this high viscosity is caused by the hydrophilicity (water absorption) of surface of suspended solid (SS) particle in the slurry, it is expected that H retention would be repressed by coating (modifying) this surface with much lower hydrophilic materials (molecules). In order to discuss the degree of repression quantitatively, it is important to estimate the hydrophilicity of SS particle surface. In this report as the first in a series of presentations, the water vapor adsorption behavior on the SS particle surface was measured under two conditions of drying and moisture adsorption by using a gas adsorption measurement apparatus, and the hydrophilicity of SS particle surface was estimated for the current and hydrophilicity-lowered slurries to be compared with each other.
Tanaka, Takuro*; Saito, Takumi*; Toda, Kanako*; Fujiwara, Kenso; Terashima, Motoki; Nakanishi, Takahiro; Kobayashi, Natsuko*; Tanoi, Keitaro*
no journal, ,
Cs-137 dispersed by the Fukushima Daiichi Nuclear Power Plant accident deposited in Fukushima area, that are not decontaminated in mountainous areas, may migrate through river water to animals and plants. Most of Cs-137 in river are fixed in clay minerals, but there are some Cs that can be easily desorbed, named as labile components. It has been suggested that labile components affect the bioavailability of Cs-137. In this study, the labile Cs-137 was sampled in situ from upstream to downstream in several rivers of Fukushima using a passive sampler called diffusive gradients in thin films (DGT). Sampling was conducted at a different season in addition to the previous studies.
Cs in Fukushima rivers by diffusive gradients in thin films (DGT), 3; Relations between geochemical parametersTanaka, Takuro*; Saito, Takumi*; Toda, Kanako*; Fujiwara, Kenso; Terashima, Motoki; Nakanishi, Takahiro; Kobayashi, Natsuko*; Tanoi, Keitaro*; Kato, Hiroaki*
no journal, ,
Cs dispersed by the Fukushima Daiichi Nuclear Power Plant accident deposited in Fukushima area, that are not decontaminated in mountainous areas, may migrate through river water to animals and plants. Most of Cs in river are fixed in clay minerals, but there are some Cs that can be easily desorbed, named as labile components. It has been suggested that labile components affect the bioavailability of Cs. In this study, the labile Cs was sampled in situ from upstream to downstream in several rivers of Fukushima using a passive sampler called diffusive gradients in thin films (DGT). The desorption behavior of the labile component and factors affecting it will be discussed by examining the relationship with particulate Cs and geochemical parameters in river water.
