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-ray irradiation in HNO
mediaNogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Kawata, Yoshihisa*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
Journal of Radioanalytical and Nuclear Chemistry, 296(1), p.423 - 427, 2013/04
Times Cited Count：5 Percentile：38.62(Chemistry, Analytical)Stability of polyvinylpolypyrrolidone (PVPP), a resin with adsorption selectivity to U(VI) in nitric acid media, against -ray irradiation has been examined using HNO solutions of various concentrations. As the result, no clear decrease in the capacity was observed for any samples. Or rather, it was found that the capacity increased by approximately 50% for the PVPP slurry irradiated in 6 M HNO. The infrared spectroscopic study indicates that PVPP degrades by -ray irradiation in HNO from the cleavage of the pyrrolidone ring by the addition of oxygen atom originating from HNO, followed by the formation of chain monoamides with multiple coordinative atoms by the continuous addition of oxygen, finally leading to the generation of primary-amine type anion exchange resin. It is also indicated that all generated functional groups possess adsorptivity to U(VI) in 3 M HNO.
-ray irradiationNogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Kawata, Yoshihisa*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
Science China; Chemistry, 55(9), p.1739 - 1745, 2012/09
Times Cited Count：4 Percentile：19.69(Chemistry, Multidisciplinary)Stability of N-alkylated pyrrolidone derivatives (NRPs) against radiation was examined by irradiation tests with 
Co -ray. We have been developed a novel reprocessing system using NRPs which have precipitation ability to haxa- and tetravalent actinides in nitric acid media. Degradation rates of NRPs are evaluated by irradiation in 3M nitric acid solutions and mechanism of degradation are discussed in the present paper.
Ikeda, Yasuhisa*; Kawasaki, Takeshi*; Harada, Masayuki*; Nogami, Masanobu*; Kawata, Yoshihisa*; Kim, S.-Y.*; Morita, Yasuji; Chikazawa, Takahiro*; Someya, Hiroshi*; Kikuchi, Toshiaki*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
An advanced reprocessing system for spent FBR fuels based on two precipitation processes using pyrrolidone derivatives as precipitants has been developed. Experimental results of precipitation behavior of U, Pu and other elements, the heat- and radiation-resistance of precipitants, the thermal decomposition properties of precipitates showed that N-n-butyl-2-pyrrolidone and N-neopentyl-2-pyrrolidone are the appropriate precipitants for the first and second precipitation steps, respectively. From the engineering investigation, We confirmed that the precipitation and the filtration can be done efficiently using the engineering scale equipment and that the fuel pellets are directly prepared by the calcination of the precipitates. On the basis of these results, we evaluated that the proposed system is expected to be one of candidates of the future reprocessing systems for spent FBR fuels.
Nogami, Masanobu*; Harada, Masayuki*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Kawata, Yoshihisa*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
Progress in Nuclear Energy, 53(7), p.948 - 951, 2011/09
Times Cited Count：3 Percentile：26.02(Nuclear Science & Technology)The precipitation ability of 1,3-dimethyl-2-imidazolidone (DMI) to U(VI) and U(IV) was examined using nitric acid solutions. While DMI precipitated U(VI) from 3 M nitric acid, no precipitate was observed in the solution containing 0.15 M U(IV) and 3 M nitric acid by adding DMI at the ratio of [DMI]/[U(IV)]=5. This indicates that the selectivity of DMI to U(VI) than U(IV). In spite of the excellent selectivity to U(VI), DMI has a disadvantage on the stability in nitric acid, because gradual acid hydrolysis of DMI is inevitable due to the nature of the chemical structure. Experiments on the stability of DMI in -ray irradiation and heating in nitric acid solutions showed that the stability is strongly affected by the concentration of nitric acid and that DMI may be applicable in nitric acid solutions up to ca. 2 M.
and PuKim, S.-Y.; Takao, Koichiro*; Haga, Yoshinori; Yamamoto, Etsuji; Kawata, Yoshihisa; Morita, Yasuji; Nishimura, Kenji*; Ikeda, Yasuhisa*
Crystal Growth & Design, 10(5), p.2033 - 2036, 2010/04
Times Cited Count：15 Percentile：77.61(Chemistry, Multidisciplinary)Plutonyl(VI) nitrate complexes with N-cyclohexyl-2-pyrrolidone (NCP) and N-neopentyl-2-pyrrolidone (NNpP) were prepared, and their molecular and crystal structures were determined by single crystal X-ray analysis. The obtained compounds have the similar composition, PuO
(NO)(NRP) (NRP = NCP, NNpP), which are analogous to the corresponding U(VI) complexes. Both PuO(NO)(NRP) complexes show typical structural properties of actinyl(VI) nitrates, i.e., hexagonal-bipyramidal geometry consisting of two NRP molecules and two NO
ions located in trans positions in the equatorial plane of PuO
moiety. These findings provide one of criteria in selection of suitable NRP as a precipitation agent for the spent nuclear fuel reprocessing based on the precipitation method.
Morita, Yasuji; Kim, S.-Y.; Kawata, Yoshihisa; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.1081 - 1085, 2009/09
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives, which consists of two precipitation steps; the first selective U precipitation step and the second U-Pu co-precipitation step. In the present study, precipitation behavior of Pu with pyrrolidone derivatives with high precipitation ability of N-(1,2-dimethyl)propyl-2-pyrrolidone (NDMProP), N-neopenthyl-2-pyrrolidone (NNpP) and N-cyclohexyl-2-pyrrolidone (NCP) has been examined with solutions of U-Pu mixture in order to evaluate their applicability to the second step. Since NNpP showed the highest precipitation ability for Pu(IV) and the best physical property as precipitate, NNpP would be the most appropriate precipitant for the U-Pu co-precipitation process. Precipitation of Np(IV, V, VI) with NNpP was also examined and it was found that Np(VI) could be quantitatively co-precipitated with U(VI) and Pu(IV).
Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kawata, Yoshihisa; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the durability of N-n-butyl-2-pyrrolidone (NBP) against -irradiation and heat and the mechanism of degradation were examined in the various conditions. NBP is the most promising candidate as the precipitant for the first step in which U is selectively separated. The results showed that many kinds of multi-functional degradation products were formed by irradiation and heating and therefore that the influence of these degradation products on the following step in the reprocessing system should be investigated in detail.
Harada, Masayuki*; Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Ikeda, Yasuhisa*; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the effects of addition of masking agent for Pu(IV) in the first selective U precipitation step were investigated to suppress the Pu co-precipitation using U(IV) as a substitute for Pu(IV). The results showed that amide compounds such as N, N-dimethyl-acetamide have relatively high masking ability.
Kawasaki, Takeshi*; Nogami, Masanobu*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the recovery of precipitant from the precipitate through vaporization by heating was investigated using N-n-butyl-2-pyrrolidone (NBP) and N-n-neopentyl-2-pyrrolidone (NNpP) as precipitants. Experimental results showed that the most of the precipitants can be recovered without degradation and therefore the precipitants can be reused.
-ray irradiationNogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kawata, Yoshihisa*; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the decomposition of residual precipitants in the solution after precipitation was examined by -ray irradiation of 9M nitric acid solution containing N-n-butyl-2-pyrrolidone (NBP) which would be used in the first selective U precipitation step. We found that NBP can be easily decomposed by -ray but oxalic acid, acetic acid and other products by the decomposition remain in the solution. Further study is required for the complete decomposition of organic reagents.
Kim, S.-Y.*; Morita, Yasuji; Kawata, Yoshihisa*; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. The system composed of the first precipitation step for selective U separation with N-n-butyl-2-pyrrolidone (NBP), concentration step and the second precipitation step for Pu and residual U separation with N-neopenthyl-2-pyrrolidone (NNpP). The present study revealed the effects of heating in the concentration step, Pu concentration and Pu oxidation state, on the Pu precipitation behavior in the second step. Experimental results showed that residual precipitant from the first step is decomposed in the concentration step and the products would reduced the precipitation yield of Pu(IV) in particular.
Kikuchi, Toshiaki*; Chikazawa, Takahiro*; Someya, Hiroshi*; Morita, Yasuji; Ikeda, Yasuhisa*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. Precipitation behavior of U(VI), separation and washing of the precipitate and the operability of engineering scale equipment were examined using solutions of U(VI) and simulated fission products. The precipitate obtained was used in basic and engineering scale tests for precipitant recovery step and fuel production step. The results showed the feasibility of the system from an engineering point of view.
Ikeda, Yasuhisa*; Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
Based on results obtained by "Development of Advanced Reprocessing System Using Highly Selective and Controllable Precipitants", the system was totally evaluated from various viewpoints. As a result, the advanced reprocessing by precipitation would be feasible as reprocessing system and become a candidate for reprocessing system for FBR spent fuel.
