Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
-alkylated 2-pyrrolidone derivativesTakao, 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：15.91(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.
-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：6 Percentile：41.29(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：18.93(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：30.95(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：76.79(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.
-ray irradiationNogami, 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：19 Percentile：74.61(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.
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).
Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Ikeda, Yasuhisa*; Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*
Journal of Nuclear Science and Technology, 44(3), p.354 - 360, 2007/03
Times Cited Count：16 Percentile：70.75(Nuclear Science & Technology)Precipitation behavior of Pu and other transuranium elements with N-cyclohexyl-2-pyrrolidone (NCP) has been examined to develop a simple reprocessing based only on precipitation method. From HNO solutions containing only Pu, both Pu(VI) and Pu(IV) were precipitated with NCP, but they required more NCP than in the U(VI) precipitation. Selective U(VI) precipitation from HNO solution containing U(VI) and Pu(IV) was achieved by stirring the solution for sufficient time after addition of NCP with ratio of [NCP]/[U]=1.4. Addition of an enough amount of NCP to U(VI)-Pu(VI) or U(VI)-Pu(IV) solutions gave a quantitative precipitation of both U and Pu. Neither Am(III) nor Np(V) was precipitated in the selective U precipitation and the simultaneous U-Pu precipitation. These results demonstrate the feasibility of the reprocessing by precipitation with NCP.
Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Ikeda, Yasuhisa*; Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
N-cyclohexyl-2-pyrrolidone (NCP) can selectively precipitate U(VI) ions in aqueous nitric acid solutions. Utilizing this property, we have been developing a simple reprocessing process of spent nuclear fuel based only on precipitation method. In the first precipitation step, only U is separated by precipitation in a yield of about 70%, and in the second precipitation step both U and Pu are recovered and separated from fission products (FP) and other transuranium elements (TRU). In JAERI, precipitation behaviors of Pu and other TRU were examined experimentally, and the results showed the feasibility of the process establishement.
Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*; Morita, Yasuji; Kawata, Yoshihisa*; Mineo, Hideaki; Koshino, Nobuyoshi*; Asanuma, Noriko*; Harada, Masayuki*; et al.
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 4 Pages, 2005/10
N-cyclohexyl-2-pyrrolidone (NCP), can selectively precipitate U(VI) ions in aqueous nitric acid solutions. Utilizing this property, we have been developing a simple reprocessing process of spent nuclear fuel based only on precipitation method. In the first precipitation step, only U is separated by precipitation in a yield of about 70%, and in the second precipitation step both U and Pu are recovered and separated from fission products (FP) and other transuranium elements (TRU). In the present study, a precipitator and a precipitate separator were designed and built up, and were tested with aspets of operationability and system performance.
Morita, Yasuji; Kim, S.-Y.; Kawata, Yoshihisa; Sato, Makoto; Ikeda, Yasuhisa*; Takao, Koichiro*; Noda, Kyoko*; Nishimura, Kenji*
no journal, ,
Precipitation behavior of Pu with pyrrolidone derivatives of N-(1,2-dimethyl)propyl-2-pyrrolidone (NDMProP) and N-neopenthyl-2-pyrrolidone (NNpP) in the solutions of U-Pu mixture has been examined in order to evaluate their applicability to the U-Pu co-precipitation process in the reprocessing based only on precipitation method. We have previously developed a process with N-cyclohexyl-2-pyrrolidone (NCP). It was found that U(VI) was precipitated in a high yield with any of the three precipitants and the precipitation yield of Pu(IV) was increased with the added amount of the precipitants. When NNpP was added with the ratio of [NNpP]/[U+Pu]=2.5, 99.5% of Pu was precipitate. 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.
Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*; Kawata, Yoshihisa; Morita, Yasuji
no journal, ,
In the novel reprocessing system under development for spent FBR fuels based on the precipitation method, U and Pu of very low concentrations remain in the supernatant after almost all U and Pu in the dissolvent solution are separated by precipitation. The remaining U and Pu are supposed to be removed by an adsorption method using polyvinylpolypyrrolidone (PVPP) which is insoluble in water. In this study, stability of PVPP in HNO solutions under -ray irradiation was investigated. As the result, remarkable decreases in the capacity were not found in all samples. Or rather, the capacity was found to be increased for the sample irradiated in 6M HNO for 0.90 MGy. These facts revealed that PVPP maintains the adsorptivity to U(VI) under various concentrations of HNO for 10 days of operation under -ray irradiation.
Kawata, Yoshihisa; Kim, S.-Y.; Sato, Makoto; Morita, Yasuji; 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. In the present study, 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) were tested using real fuel solution. U(VI) was precipitated as expected both in the first and second precipitation steps. In the concentration step, a part of Pu(IV) was oxidized to Pu(VI). The behavior pf Pu in the second precipitation step seemed to be influenced by the concentration step.
Kim, S.-Y.; Kawata, Yoshihisa; Morita, Yasuji; Ikeda, Yasuhisa*; Nishimura, Kenji*
no journal, ,
Precipitation behavior of Pu with pyrrolidone derivatives of N-n-butyl-2-pyrrolidone (NBP), N-propyl-2-pyrrolidone (NProP) and N-iso-butyl-2-pyrrolidone (NiBP) in the solutions of only Pu and U-Pu mixture has been examined in order to evaluate their applicability to the selective U precipitation process in the reprocessing based only on precipitation method. We have previously developed a process with N-cyclohexyl-2-pyrrolidone (NCP). It was found that the precipitation ability of NBP, NProP and NiBP is lower than that of NCP and the lower co-precipitation and faster re-dissolution of Pu(IV) in the mixed solution of U(VI) and Pu(IV) was obtained in the precipitation with NBP, NProP and NiBP than with NCP. From these results, it is expected that those new precipitants would make the selective U precipitation process more selective and effective.
Nogami, Masanobu*; Noda, Kyoko*; Takao, Koichiro*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kawata, Yoshihisa; 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 durability of new precipitants with low and high hydrophobicity against -irradiation and heating. Results showed that the precipitants with low hydrophobicity, N-n-butyl-2-pyrrolidone, N-propyl-2-pyrrolidone and N-iso-butyl-2-pyrrolidone, have enough durability against -irradiation. The precipitants with high hydrophobicity, N-cyclohexyl-2-pyrrolidone, N-(1,2-dimethyl)propyl-2-pyrrolidone and N-neopenthyl-2-pyrrolidone, also have enough durability but gave lower precipitation yield when they irradiated with higher dose rate. The precipitation ability of all the precipitants did not changed by the heating at 50
C for three days.
Harada, Masayuki*; Nogami, Masanobu*; Sugiyama, Yuichi*; Kawasaki, Takeshi*; 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 masking effect of some reagents was examined for the purpose of the reduction of Pu(IV) co-precipitation in the first selective U precipitation step using N-n-butyl-2-pyrrolidone (NBP) as a precipitant. Experiments with nitric acid solutions of U(VI)-Pu(IV) showed the masking effect of N-n-methyl-2-pyrrolidone (NMP) for Pu(IV).
-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.
