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Am and 
Np capture cross sections
erovnik, G.*; Schillebeeckx, P.*; Cano-Ott, D.*; Jandel, M.*; Hori, Junichi*; Kimura, Atsushi; Rossbach, M.*; Letourneau, A.*; Noguere, G.*; Leconte, P.*; et al.
EPJ Web of Conferences, 146, p.11035_1 - 11035_4, 2017/09
Times Cited Count：3 Percentile：82.51(Nuclear Science & Technology)Np content in spent nuclear fuelAsai, Shiho; Hanzawa, Yukiko; Konda, Miki; Suzuki, Daisuke; Magara, Masaaki; Kimura, Takaumi; Ishihara, Ryo*; Saito, Kyoichi*; Yamada, Shinsuke*; Hirota, Hideyuki*
Analytical Chemistry, 88(6), p.3149 - 3155, 2016/03
Times Cited Count：8 Percentile：25.67(Chemistry, Analytical)Neptunium-237 (Np) is one of the major long-lived radionuclides found in spent nuclear fuel. To evaluate the long-term safety of a HLW repository, the Np content in spent nuclear fuel must be determined. In this study, micro-volume anion-exchange porous polymer disk-packed cartridges were prepared for Am-Np separation, which is required prior to the measurement of Np with ICP-MS. Disks with a volume of 0.08 cm
were cut out from porous sheets having triethylenediamine (TEDA)-containing polymer chains densely attached on the pore surface. The resulting TEDA-introduced disk cartridge was applied to a spent nuclear fuel sample. The chemical yield of Np was 90.4%, which is sufficiently high for ICP-MS measurement of Np. Compared with the conventional separation technique using commercially available anion-exchange resin columns, the time required to adsorb, wash and elute Np using the TEDA-introduced disk cartridge was reduced by 75%.
Saeki, Masakatsu; Nakada, Masami; Kawasaki, Takeshi*; Nishimura, Tatsuru*; Kitazawa, Takafumi*; Takeda, Masuo*
Journal of Radioanalytical and Nuclear Chemistry, 270(2), p.379 - 384, 2006/11
Times Cited Count：3 Percentile：23.21(Chemistry, Analytical)no abstracts in English
Saeki, Masakatsu
JAERI-Review 2004-011, 54 Pages, 2004/03
JAERI-Review-2004-011.pdf:5.21MB
In this review, experimental results on studies of radioactive iodine, tritium and neptunium are summarized. On studies of radioactive iodine, from various experimental results, the process establishing the formation mechanism of organic iodides was fully described. On the basis of formation mechanism, possibilities for the formation of organic iodides under nuclear reactor accidents and so on were also discussed. On studies of tritium, three topics were concisely described on the isotopic composition of tritium gases, the chemical forms and the diffusivity of tritium in various materials, and the sorption and desorption behaviors of tritium on surfaces of various materials. On the neptunium chemistry, the relationship between the structure of neptunium compound and the Moessbauer isomer shift and experimental results on neptunyl(VI) hydroxides were discussed.
Mukai, Masayuki; Tanaka, Tadao; Maeda, Toshikatsu; Ogawa, Hiromichi; Matsumoto, Junko; Munakata, Masahiro; Zhao, Y.*; Guo, Z.*; Ni, S.*; Li, S.*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(3), p.342 - 349, 2003/09
Evaluation of radionuclide migration in geologic media is of great importance in safety assessment for shallow land disposal specially for TRU nuclides because of inadequate data based on field test. As a cooperative research between JAERI and CIRP, a field test of radionuclide migration was conducted under natural condition using Sr-90, Np-237 and Pu-238 to obtain migration data of the radionuclides in actual aerated layer under natural rainfall condition. Values of input parameters to an existing evaluation equation of nuclide migration were determined on the basis of the results of laboratory experiments of batch and column methods and field investigation. Migration distribution of the radionuclides calculated with the determined values showed reasonable agreement with the measured distribution of the field test. This confirmed an applicability of the evaluation equation for radionuclide migration to actual aerated layer under natural condition.
Sr, Np, 
Pu and Am in loess media (Joint research)Tanaka, Tadao; Mukai, Masayuki; Maeda, Toshikatsu; Matsumoto, Junko; Ogawa, Hiromichi; Li, S.*; Wang, Z.*; Wang, J.*; Guo, Z.*; Zhao, Y.*
JAERI-Research 2002-034, 20 Pages, 2002/12
JAERI-Research-2002-034.pdf:1.1MB
Adsorption mechanisms and models of Sr(II), Np(V), Pu(IV) and Am(III) on the loess were investigated from their adsorption and desorption properties. The distribution coefficient of Sr and Np was 2 - 3 orders of magnitude smaller than that of Pu and Am. The adsorption of Sr and Np was mainly controlled by the ion exchange reaction. On the other hand, the adsorption of Pu and Am was mostly controlled by the selective chemical reactions with Fe and Mn oxyhydroxide/oxide and humic substances. On the basis of the experimental results, several types of adsorption models of the radionuclides, considering elemental concentrations, adsorption mechanisms and kinetics, were proposed for setting up the analytical systems of radionuclide migration in the loess media.
Mineo, Hideaki; Uchiyama, Gunzo; Hotoku, Shinobu; Asakura, Toshihide; Kihara, Takehiro; ; ; Kimura, Shigeru; ; ; et al.
Proc. of Int. Conf. on Future Nuclear Systems (GLOBAL'99)(CD-ROM), 7 Pages, 1999/00
no abstracts in English
Oigawa, Hiroyuki; Shinohara, Nobuo; Mukaiyama, Takehiko; H.H.Saleh*; T.A.Parish*; W.H.Miller*; S.Raman*
Proc. of 4th Int. Information Exchange Meeting on Actinide and Fission Product Partitioning and Transm, 0, p.341 - 346, 1997/00
no abstracts in English
U,Np, and 
AmH.H.Saleh*; T.A.Parish*; W.H.Miller*; Oigawa, Hiroyuki; S.Raman*
Nuclear Instruments and Methods in Physics Research B, 103, p.393 - 400, 1995/00
Times Cited Count：2 Percentile：31.76(Instruments & Instrumentation)no abstracts in English
Np in spent nuclear fuels; K.Kammerichs*; L.Koch*
Journal of Radioanalytical and Nuclear Chemistry, Letters, 117(4), p.233 - 241, 1987/04
no abstracts in English
Nakamura, Shoji; Terada, Kazushi; Kimura, Atsushi; Nakao, Taro; Iwamoto, Osamu; Harada, Hideo; Uehara, Akihiro*; Fujii, Toshiyuki*
no journal, ,
As a part of the AIMAC Project, our group have measured the cross sections for Minor Actinides by an activation method with research reactors. In this presentation, we will clear up the cause of discrepancies among reported data for Np-237 in terms of the 
-ray emission probability, experimental method and so on.
Irisawa, Eriko*; Kato, Chiaki; Yamashita, Naoki; Sano, Naruto
no journal, ,
In the reprocessing of spent nuclear fuel, stainless steel components are exposed to highly corrosive environments, including concentrated nitric acid and gamma-ray irradiation from fission products. This study investigates the effect of gamma-ray irradiation on the corrosion behavior of ultra-low carbon stainless steel (R-SUS304ULC) in nitric acid solutions containing Neptunium-237 (Np). Immersion corrosion tests and electrochemical measurements, including polarization resistance and potentiostatic methods, were conducted under irradiation using the 
Co gamma-ray source. Immersion corrosion tests and electrochemical measurements, including polarization resistance and potentiostatic methods, were conducted using a Co gamma-ray source (maximum dose rate: 3.2 kGy/h). The results showed that at 55
C, gamma-ray irradiation significantly reduced the corrosion rate, attributed to the radiolytic generation of nitrous acid (HNO
), which reduces hexavalent neptunium (NpO), thereby lowering the oxidizing potential of the solution. At 80C, this effect was diminished due to thermal decomposition of HNO;. The polarization resistance method was validated as a reliable technique for estimating corrosion rates in Np-containing nitric acid solutions. However, under irradiation, the conversion coefficient (K) was found to be lower than expected, likely due to changes in anodic polarization behavior. Potentiostatic measurements further revealed that the increase in anodic current under irradiation was not solely due to metal dissolution. A portion of the current was attributed to other oxidation reactions, possibly involving HNO; or radiolysis-derived species from nitric acid. These findings enhance the understanding of corrosion mechanisms in nuclear fuel reprocessing environments and highlight the importance of accounting for radiation-induced chemical changes when evaluating material performance. Further investigation into the nature of these additional oxidation reactions is necessary to improve corrosion prediction models under irradiation conditions.
Np in variable neutron field at KURRI-LINACTakahashi, Yoshiyuki*; Hori, Junichi*; Sano, Tadafumi*; Yashima, Hiroshi*; Nakamura, Shoji; Harada, Hideo
no journal, ,
Np fission chamberIwamoto, Hiroki; Meigo, Shinichiro; Satoh, Daiki; Iwamoto, Yosuke; Sugihara, Kenta*; Ishi, Yoshihiro*; Uesugi, Tomonori*; Kuriyama, Yasutoshi*; Yashima, Hiroshi*; Nishio, Katsuhisa; et al.
no journal, ,
no abstracts in English
Np by TOF method at KURRI-LINACHori, Junichi*; Yashima, Hiroshi*; Sano, Tadafumi*; Takahashi, Yoshiyuki*; Harada, Hideo
no journal, ,
Neutron capture and total cross sections of Np have been measured by utilizing neutron time-of-flight method at KURRI-LINAC facility under the frame work of the research project "R&D for accuracy improvement of neutron nuclear data on minor actinides". Obtained results are compared with reported measurement values and evaluated data.
