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Suzuki, Tomoya; Takao, Koichiro*; Kawasaki, Takeshi*; Harada, Masayuki*; Nogami, Masanobu*; Ikeda, Yasuhisa*
Polyhedron, 96, p.102 - 106, 2015/08
Times Cited Count:7 Percentile:49.76(Chemistry, Inorganic & Nuclear)We have determined crystal structures of UO(NO)() (: 2-imidazolidone), UO(NO)() (: tetrahydro-2-pyrimidone) and UO(NO)() (: 1-methyl-2-imidazolidone) by using single crystal X-ray analysis, and examined correlations between melting points (mps) and intermolecular hydrogen bonds (HBs) of UO(NO)(CU) (CU: cyclic urea derivatives) and UO(NO)(NRP) (NRP: pyrrolidone derivative).
Takao, Koichiro*; Kawata, Yoshihisa*; Nogami, Masanobu*; Harada, Masayuki*; Morita, Yasuji; Nishimura, Kenji*; Ikeda, Yasuhisa*
Journal of Nuclear Science and Technology, 52(2), p.294 - 298, 2015/02
Times Cited Count:2 Percentile:16.69(Nuclear Science & Technology)Yields of precipitated UO(NO)(NRP) (NRP = -alkylated 2-pyrrolidone) were precisely determined by considering reduction of the solution volume through the precipitation, which can be estimated from difference in acid concentrations of the liquid phases before and after the precipitation. The studied NRPs were --butyl (NBP) and --propyl (NProP) derivatives. In both systems, the precipitation yields precisely determined were always higher than those simply calculated from the ratio of uranium concentrations before and after the precipitation. However, the differences between them are in the range of 0.6% - 2.6%. If such a difference is practically negligible, the volume reduction through the precipitation does not have to be taken into account for simplicity of the analytical manipulation.
Nogami, 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:37.27(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.
Nogami, 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:19.35(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:4 Percentile:31.74(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.
Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
Journal of Radioanalytical and Nuclear Chemistry, 283(2), p.541 - 546, 2010/02
Times Cited Count:20 Percentile:77.87(Chemistry, Analytical)Adsorptivity of polyvinylpolypyrrolidone (PVPP) to various metal ions was examined as a part of the development of resins with selectivity to U(VI) in nitric acid media. It was found that PVPP has a strong adsorptivity to U(VI) in wide concentration range of nitric acid. The mechanism of U(VI) adsorption by PVPP was discussed by results of Scatchard plot analysis and infrared spectroscopic analysis. Furthermore, it was found that fission productions except for Re(VII) as the simulant of Tc(VII) and Pd(II) are not adsorbed on to PVPP and that Pd(II) and Re(VII) species are weakly adsorbed in the lower concentration ranges of nitric acid, where the adsorption rates of Pd(II) are extremely slower than those of U(VI). These results indicate that U(VI) can be separated from other metal ions by PVPP.
Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Kawata, Yoshihisa; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 25, 2009/12
As a part of the development of a novel reprocessing system for spent FBR fuels based on the precipitation method, influence of concentrations of HNO on the stability by -ray irradiation was examined for --butyl-2-pyrrolidone (NBP), a candidate precipitant for the first precipitation step for selectively precipitating U(VI). The residual ratios of the samples for HNO solutions up to 3 M were found to be decreased identically, where ca. 20% of NBP was degraded after the irradiation of 1 MGy. It was found that the degradation of the samples of 6 M HNO is more distinguished, where ca. 30% was degraded after the irradiation of 0.1 MGy. As the result of the investigation of the degradation mechanism of NBP, it was revealed that the degradation started from the cleavage of the pyrrolidone ring of NBP by the addition of oxygen atom, followed by the formation of chain monoamides and C4 compounds by the continuous addition of oxygen, leading to the generation of oxalic acid.
Morita, Yasuji; Takao, Koichiro*; Kim, S.-Y.; Kawata, Yoshihisa; Harada, Masayuki*; Nogami, Masanobu*; Nishimura, Kenji*; Ikeda, Yasuhisa*
Journal of Nuclear Science and Technology, 46(12), p.1129 - 1136, 2009/12
Times Cited Count:18 Percentile:73.96(Nuclear Science & Technology)A reprocessing system for spent FBR fuels consisting of two precipitation processes has been proposed. In this system, first only U(IV) species are precipitated using pyrrolidone derivative with low hydrophobicity and donicity, and secondly residual U(VI) and Pu(IV, VI) are precipitated simultaneously using pyrrolidone derivative with high precipitation ability. In this study, we have examined precipitation behavior of U(VI), Pu(IV), and Pu(VI) species in nitric acid solutions by using --propyl-2-pyrrolidone (NProP), -butyl-2-pyrrolidone (NBP), --butyl-2-pyrrolidone (NiBP), or -cyclohexyl-2-pyrrolidone (NCP) to select the precipitants for the first precipitation process. As a result, NBP were found to be the most promising precipitant for the first precipitation process.
Takao, Koichiro*; Noda, Kyoko*; Nogami, Masanobu*; Sugiyama, Yuichi*; Harada, Masayuki*; Morita, Yasuji; Nishimura, Kenji*; Ikeda, Yasuhisa*
Journal of Nuclear Science and Technology, 46(10), p.995 - 999, 2009/10
Times Cited Count:14 Percentile:66.12(Nuclear Science & Technology)We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In the present study, the solubility of UO(NO)(NRP) (NRP = -alkyl-2-pyrrolidone, alkyl = -propyl, -butyl, -butyl and cyclohexyl) in aqueous solutions with HNO has been examined. As a result, the solubility of each species of UO(NO)(NRP) generally decreases with increasing concentrations of HNO and NRP ((HNO) and (NRP), respectively). The solubility of UO(NO)(NRP) also depends on the type of NRP; a higher hydrophobicity of NRP generally leads to a lower solubility of UO(NO)(NRP). The logarithms of effective solubility products () of UO(NO)(NRP) at different (HNO) values and 293 K were evaluated.
Ikeda, Yasuhisa*; Takao, Koichiro*; Harada, Masayuki*; Morita, Yasuji; Nogami, Masanobu*; Nishimura, Kenji*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1503 - 1507, 2007/09
We have developed a reprocessing process for spent FBR fuels based on the precipitation method using pyrrolidone derivatives. In previous investigation, N-cyclohexyl-2-pyrrolidone (NCP) is used as a precipitant and a process consisting of selective U precipitation step and U-Pu co-precipitation step was developed. In the present study, in order to examine the applicability of precipitants with lower hydrophobicity than NCP to the selective U precipitation step, we have carried out precipitation experiments of U(VI) by N-butyl-2-pyrrolidone (NBP) and N-propyl-2-pyrrolidone (NProP) and measured decontamination factors of some fission products.
Morita, Yasuji; Kim, S.-Y.; Ikeda, Yasuhisa*; Nogami, Masanobu*; Nishimura, Kenji*
Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1508 - 1512, 2007/09
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In previous investigation, N-cyclohexyl-2-pyrrolidone (NCP) is used as a precipitant and a process consisting of selective U precipitation step and U-Pu co-precipitation step was developed. In order to make the process more effective and more economical, we are now studying precipitation of U and Pu with other pyrrolidone derivatives. In the present study, precipitation behavior of Pu was examined using N-butyl-2-pyrrolidone (NBP) and N-propyl-2-pyrrolidone (NProP), which have lower hydrophobicity than NCP. The experiments with Pu(IV) or Pu(VI) solutiona and U(VI)-Pu(IV) solutions showed that Pu is less precipitated with NBP or NProP than with NCP. From these results, it is expected that NBP and NProP can be used as precipitants for the selective U precipitation step and make the step more selective and effective.
Koshino, Nobuyoshi*; Harada, Masayuki*; Nogami, Masanobu*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*
Inorganica Chimica Acta, 358(6), p.1857 - 1864, 2005/03
Times Cited Count:54 Percentile:88.17(Chemistry, Inorganic & Nuclear)Structural analyses of UO(NO)L [L=-butyl-2-pyrrolidone, N-cyclohexylmethyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidone] have been carried out using X-ray diffraction method. These uranyl complexes were found to have a hexagonal bipyramidal structure. The bond distances of U=O and U-O (ligand), and bond angles of U-O-C(carbonyl) are determined. In uranyl nitrate complexes with cyclic amides such as 2-pyrrolidone, urea, and caprolactam derivatives, a linear correlation was found to hold between U-O (ligand) bond distances and U-O-C(carbonyl) bond angles. Vibrational frequencies of UO(NO)L have also been measured by IR and Raman spectrophotometers. Using relationships between vibrational frequencies of O=U=O bonds and donor numbers (DNs) of ligands, donicities of N-substituted-2-pyrrolidones were determined.
Nogami, Masanobu*; Kawasaki, Takeshi*; Takao, Koichiro*; Noda, Kyoko*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; et al.
no journal, ,
A reprocessing system for spent FBR fuels based on the two precipitation processes has been proposed. In this system, first only U(VI) species are precipitated using pyrrolidone derivatives (NRP) with low hydrophobicity and donicity, and secondly residual U(VI) and Pu(IV, VI) are precipitated simultaneously using pyrrolidone derivative with high precipitation ability. In order to develop such a reprocessing method, behavior of uranyl ions in HNO has been studied using various novel NRP. In this presentation, recent advances on precipitation behavior and of uranyl ions and calcination of U(VI)-NRP will be introduced.
Kim, S.-Y.; Kawata, Yoshihisa; Morita, Yasuji; Nogami, Masanobu*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*; Nishimura, Kenji*
no journal, ,
A reprocessing system for spent FBR fuels based on the two precipitation processes has been proposed. In this system, first only U(VI) species are precipitated using pyrrolidone derivatives (NRP) with low hydrophobicity and donicity, and secondly residual U(VI) and Pu(IV, VI) are precipitated simultaneously using pyrrolidone derivative with high precipitation ability. It is important to control precipitation of Pu(IV), and recent advances on precipitation behavior of Pu(IV, VI) by using novel pyrrolidone derivatives will be introduced in this presentation. Precipitation tests using mixed solutions of U(VI) and Pu(IV) showed that N-n-butyl-2-pyrrolidone (NBP) is the most appropriate precipitant for the first precipitation step and N-neopenthyl-2-pyrrolidone (NNpP) is the most appropriate precipitant for the second step.
Kawasaki, Takeshi*; Nogami, Masanobu*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji; Kikuchi, Toshiaki*
no journal, ,
Recovery of the precipitant by evaporation of the precipitates of U(VI) with pyrrolidone derivatives was investigated for the development of an advanced reprocessing system for spent FBR fuels based only on precipitation method. It was found that the U(VI) precipitate with N-n-butyl-2-pyrrolidone (NBP) melted at about 100C and the bubble formation was observed at 140 - 150C. Most of the recovered materials by cooling the evaporated fraction was NBP, and therefore, it is expected to recover the precipitant without degradation by this methods.
Sugiyama, Yuichi*; Nogami, Masanobu*; Kawasaki, Takeshi*; 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. The present study deals with recovery of residual U(VI) from high-level liquid waste by adsorption with polyvinylpolypyrrolidone (PVPP) after the main precipitation step. Batch experiments showed the high distribution coefficient (Kd) for U(VI) in the wide range of nitric acid concentration and higher Kd at lower nitric acid concentration. Among fission product elements, only Pd(II) was adsorbed weekly, but in the column experiment Pd was separated from U(VI) by washing the adsorbent with 3M nitric acid.
Nogami, Masanobu*; Takao, Koichiro*; Sugiyama, Yuichi*; Noda, Kyoko*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji; Nishimura, Kenji*
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. The present study deals with the effect of addition of masking agents on co-precipitation of Pu(IV) in the selective U(VI) precipitation. It was found that precipitation of U(IV), which was used as substitute for Pu(IV), was suppressed by the presence of acetohydoxamic acid.
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.