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Hoshi, Harutaka; Kikuchi, Takahiro; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi
JAEA-Research 2010-016, 70 Pages, 2010/07
We have studied selective separation of Cs and Sr, which are included in high level liquid waste (HLLW) generated from reprocessing of spent nuclear fuel and are major heat generators, by using extractant impregnated adsorbents. Cs adsorbent using calix arane derivatives showed excellent selectivity for Cs. It also showed significant stability against -irradiation. Sr adsorbent using crown ether derivatives also showed high selectivity for Sr from nitric acid solution, except for Ba and Tc. Dynamic capacity decreased ca. 30% after
-irradiation. Hot test using genuine HLLW stored in NUCEF was performed for separation of Cs and Sr through columns, respectively. Each Cs and Sr was separated from other typical fission product elements as well as the results obtained in preliminary experiments. Finally, Cs and Sr were separated according to a supposed separation scheme. Although some complexing agents were added in simulate HLLW, no negative effect was found.
Kikuchi, Takahiro; Hoshi, Harutaka; Asakura, Toshihide; Morita, Yasuji; Kimura, Takaumi; Dodbiba, G.*; Fujita, Toyohisa*
JAEA-Research 2010-010, 45 Pages, 2010/07
We have investigate that separation of Mo from simulated HLLW using various metal oxides adsorbent. Fe-Pb oxides and manganese oxide showed very high solubility in nitric acid solution. The distribution coefficient of Mo was decreased with increasing nitric acid concentration among tested adsorbents. Adsorption ability of Mo on alumina and cobalt oxide was low in 3M nitric acid. Hematite type iron oxide (Fe adsorbent) and amorphous zirconium oxide had high Mo adsorption ability, in 3M nitric acid. TRU, U and major fission products were not adsorbed on the adsorbent. So, separation of Mo can be achieved by using Fe adsorbent. A part of Mo was adsorbed irreversibly on Fe adsorbent, but reversibly-adsorbed Mo was recovered by oxalic acid, and the adsorbent was able to use repeatedly. Behavior of break-through of Mo is estimated from adsorption isotherm and overall mass transfer coefficient. We found that amount of throughput of Mo increased with decreasing grain size of the adsorbent.
Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 24, 2009/12
Minimization of radioactive waste from reprocessing process of spent nuclear fuel is strongly desired. We develop an advanced technology for separation of heat generating elements (Cs and Sr) from high level waste to optimize radioactive waste by its characteristics. Some novel solvent impregnated resins (SIRs) were prepared and these SIRs indicated promising ability to separate Cs and Sr from other typical fission products dissolved in nitric acid solution. These adsorbents contacting with nitric acid solution were exposed to ray in a vial. After the
irradiation, adsorbents were filtrated through a membrane filter. The adsorption capacity was examined by using irradiated adsorbents after drying. It is concluded that both SIRs maintained their high selectivity for Cs and Sr, respectively, after irradiation. Decreasing ratio of adsorption capacity by irradiation can be estimated from these results. It contributes significantly for conceptual design of separation plant.
Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi
no journal, ,
Novel solvent impregnated resins (SIR), which have significant selectivity for Cs or Sr, were examined their stability against irradiation. SIR was soaked in nitric acid solution and was irradiated by
Co
source. After the irradiation, resin was filtrated and air-dried. The capacity of Cs or Sr was examined by batch method. The capacity reduced with nitric acid concentration, however, it was mainly caused by elution of impregnated extractant into aqueous phase. Thus, these resins indicated rather stability against
irradiation. Selectivity was also examined through a column packed with irradiated resin. Cs or Sr was effectively separated from other typical fission products by using simulated high level liquid waste.
Kikuchi, Takahiro; Dodbiba, G.*; Wu, I.*; Fujita, Toyohisa*
no journal, ,
no abstracts in English
Yamashita, Yuji; Saso, Michitaka*; Kikuchi, Takahiro*; Kamoshida, Mamoru*
no journal, ,
We cultivated wet rice on the paddy field contaminated by radioactive cesium in Minamisouma city. We evaluated the effects of fertilization of a zeolite and a potassium manure on a transfer factor of radioactive cesium to the cultivated rice.
Dodbiba, G.*; Kikuchi, Takahiro; Fujita, Toyohisa*
no journal, ,
no abstracts in English
Yamazaki, Kazutoshi*; Takao, Hajime*; Kikuchi, Takahiro*; Kuriki, Yoshiro*; Kobayashi, Masato*; Kawakubo, Masahiro*; Shirase, Mitsuyasu*; Iwata, Yumiko*; Tochigi, Yoshikatsu*; Nakayama, Gen*; et al.
no journal, ,
Among factors affecting the corrosion behavior of carbon steel overpack, in order to consider materials (size) and realistic environmental factors which are difficult to reproduce in the laboratory scale test, engineering scale tests in the underground environment were carried out. A mock-up test of the same scale was also carried out on the ground with the aim of controlling and evaluating factors that govern the corrosion phenomenon. As a result of the test for about 3 years, there was no big difference between the average corrosion amount and the maximum corrosion amount of the simulated overpack base metal and the welded part. On the other hand, unlike the laboratory scale test, localization of corrosion due to the adhesion between the buffer material and the simulated overpack was also confirmed during the initial transient period.