Lanthanide and actinide ion complexes containing organic ligands investigated by surface-enhanced infrared absorption spectroscopy

Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.

Inorganic Chemistry, 62(1), p.474 - 486, 2023/01

https://doi.org/10.1021/acs.inorgchem.2c03618

HTTR burnup characteristic analysis with detailed axial burning region using MVP-BURN

Ikeda, Reiji*; Ho, H. Q.; Nagasumi, Satoru; Ishii, Toshiaki; Hamamoto, Shimpei; Nakano, Yumi*; Ishitsuka, Etsuo; Fujimoto, Nozomu*

JAEA-Technology 2021-015, 32 Pages, 2021/09

JAEA-Technology-2021-015.pdf:2.74MB

Burnup calculation of the HTTR considering temperature distribution and detailed burning regions was carried out using MVP-BURN code. The results show that the difference in k, as well as the difference in average density of some main isotopes, is insignificant between the cases of uniform temperature and detailed temperature distribution. However, the difference in local density is noticeable, being 6% and 8% for U and Pu, respectively, and even 30% for the burnable poison B. Regarding the division of burning regions to more detail, the change of k is also small of 0.6%k/k or less. The small burning region gives a detailed distribution of isotopes such as U, Pu, and B. As a result, the effect of graphite reflector and the burnup behavior could be evaluated more clearly compared with the previous study.

Stability of polyvinylpolypyrrolidone against -ray irradiation in HNO media

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

https://doi.org/10.1007/s10967-012-2121-3

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.

Development of advanced reprocessing system based on precipitation method using pyrrolidone derivatives as precipitants; Overall evaluation of system

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.

Identified charged hadron production in collisions at = 200 and 62.4 GeV

Adare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.

Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06

https://doi.org/10.1103/PhysRevC.83.064903

Transverse momentum distributions and yields for , and in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as and scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.

Adsorptivity of polyvinylpolypyrrolidone for selective separation of U(VI) from nitric acid media

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

https://doi.org/10.1007/s10967-009-0366-2

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.

Development of advanced reprocessing system using highly selective and controllable precipitants; Precipitation behavior of plutonium from U-Pu solution

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).

Development of a simple reprocessing process using selective precipitant for uranyl ions; Precipitation behaviors of plutonium and other transuranium elements

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.

A Structural study on uranyl (VI) nitrate complexes with cyclic amides; -butyl-2-pyrrolidone, -cyclohexylmethyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidone

Koshino, Nobuyoshi*; Harada, Masayuki*; Nogami, Masanobu*; Morita, Yasuji; Kikuchi, Toshiaki*; Ikeda, Yasuhisa*

Inorganica Chimica Acta, 358(6), p.1857 - 1864, 2005/03

https://doi.org/10.1016/j.ica.2004.12.036

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.

Development of a simple reprocessing process using selective precipitant for uranyl ions; Engineering studies on systems for precipitating and separating

Yamasaki, Kazuhiko*; Chikazawa, Takahiro*; Tamaki, Yoshihisa*; Kikuchi, Toshiaki*; Hanzawa, Masatoshi*; Morita, Yasuji; Ikeda, Yasuhisa*

Progress in Nuclear Energy, 47(1-4), p.414 - 419, 2005/00

https://doi.org/10.1016/j.pnucene.2005.05.041

The simple reprocessing method based on precipitation using N-cyclohexyl-2-pyrrolidone (NCP) as a selective precipitant for U and Pu ions from dissolved solutions of spent FBR fuels has been developed. On the basis of fundamental studies on precipitation behaviors, we designed and built up the scaled-up laboratory equipments (1/20-scale of future plant capacity of 200 tHM/y) to evaluate technological and economical feasibility. This system, which mainly consists of a precipitator and a precipitate separator, should be operated continuously from economical reasons. From the experimental results, it was confirmed that the precipitator is capable of producing UO-NCP precipitate stably with stipulated residence time (approximately 30 min), and the precipitate separator has the highly efficient separation of precipitate from the slurry. Furthermore, the parametric experiments indicated that the rinsing operation increased the efficiency in decontamination of FP elements.