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Journal Articles

Revisit of XPS studies of supersonic O$$_{2}$$ molecular adsorption on Cu(111); Copper oxides

Hayashida, Koki*; Tsuda, Yasutaka; Yamada, Takashi*; Yoshigoe, Akitaka; Okada, Michio*

ACS Omega (Internet), 6(40), p.26814 - 26820, 2021/10

We report the X-ray photoemission spectroscopy (XPS) characterization of the bulk Cu$$_{2}$$O(111) surface and 8-type and 29-type oxide structures on Cu(111) prepared by using 0.5 eV O$$_{2}$$ supersonic molecular beam (SSMB) source. We propose a new structural model for the 8-type oxide structure and also confirmed the previously proposed model for the [29] oxide structure on Cu(111), based on the O1s XPS spectra. The detection-angle dependence of the O 1s spectra supports that the nanopyramidal model is more preferable for the ($$sqrt{3}$$X$$sqrt{3}$$)R30$$^{circ}$$ Cu$$_{2}$$O(111). We also report the electronic excitations which O1s electrons suffer.

Journal Articles

Study of neutron-nuclear spin correlation term with a polarized Xe target

Sakai, Kenji; Oku, Takayuki; Okudaira, Takuya; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke; Hayashida, Hirotoshi*; Kakurai, Kazuhisa*; Shimizu, Hirohiko*; Hirota, Katsuya*; et al.

JPS Conference Proceedings (Internet), 33, p.011116_1 - 011116_6, 2021/03

In neutron fundamental physics, study of correlation term $${bf s}cdot{bf I}$$ of a neutron spin $${bf s}$$ and a target nuclear spin $${bf I}$$ is important because $${bf s}cdot{bf I}$$ term interferes to parity non-conserving (PNC) and time reversal non-conserving terms. For this study, a xenon (Xe) is an interesting nucleus because it has been observed an enhancement of PNC effect around neutron resonance peaks, and polarizes up to $$ sim 10^{-1}$$ by using a spin exchange optical pumping (SEOP) method. We would plan to develop a polarized Xe gas target with a compact in-situ SEOP system, and to study $${bf s}cdot{bf I}$$ term by utilizing epithermal neutron beams supplied from a high intense pulsed spallation neutron source. As the first step, we attempted to measure neutron polarizing ability caused by $${bf s}cdot{bf I}$$ term at a 9.6 eV s-wave resonance peak of $$^{129}$$Xe at BL10 in MLF, by detecting change $$Delta R$$ of ratio between neutron transmissions with the polarized and unpolarized Xe target. After demonstrating that our apparatus could detect small change ($$Delta R_{rm DB} , {approx},10^{-2}$$) of neutron transmissions caused by Doppler broadening effect, a signified value of $$Delta R$$ has been obtained as preliminary results. For analyzing the obtained $$Delta R$$ in detail, we are improving our nuclear magnetic resonance and electron paramagnetic resonance systems for evaluating Xe polarization independently of neutron beams.

Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:4 Percentile:76.41(Instruments & Instrumentation)

Journal Articles

The Energy-resolved neutron imaging system, RADEN

Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Nakatani, Takeshi; Segawa, Mariko; Hiroi, Kosuke; Su, Y.; Oi, Motoki; Harada, Masahide; Iikura, Hiroshi; et al.

Review of Scientific Instruments, 91(4), p.043302_1 - 043302_20, 2020/04

 Times Cited Count:15 Percentile:96.95(Instruments & Instrumentation)

Journal Articles

Development of the neutron polarizer for the T-violation search using compound nuclei

Okudaira, Takuya; Oku, Takayuki; Sakai, Kenji; Ino, Takashi*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Shinohara, Takenao; Kakurai, Kazuhisa*; Aizawa, Kazuya; Shimizu, Hirohiko*; et al.

Proceedings of Science (Internet), 356, 5 Pages, 2019/12

The technology development section carries out the development of the neutron polarization device: $$^{3}$$He Spin Filter. It is often used for the fundamental physics region. In order to explain the matter-dominated universe, a time reversal violation is necessary and searches for new physics are conducted in the world. The T-violation search using a polarized neutron beam is planned at J-PARC. A large $$^{3}$$He spin filter is needed to polarize high energy neutrons for the experiment and is developed in JAEA. Recently, we developed the accurate measurement system to evaluate the polarization of $$^{3}$$He and a vacuum system to make the $$^{3}$$He spin filter, and large $$^{3}$$He spin filters for epi-thermal neutron was made using the system. The current status of the development of the $$^{3}$$He spin filter will be talked.

JAEA Reports

Proceedings of the Fukushima Research Conference on Development of Analytical Techniques in Waste Management (FRCWM 2018); June 19th and 20th, Tomioka Town Art & Media Center, Tomioka, Futaba, Fukushima, Japan

Saegusa, Jun; Koma, Yoshikazu; Ashida, Takashi

JAEA-Review 2018-017, 259 Pages, 2018/12

JAEA-Review-2018-017.pdf:53.88MB

Collaborative Laboratories for Advanced Decommissioning Science (CLADS) is responsible to promote international cooperation in the R&D activities on the decommissioning of Fukushima Daiichi Nuclear Power Station and to develop the necessary human resources. CLADS held the Fukushima Research Conference on Development of Analytical Techniques in Waste Management (FRCWM 2018) on 19th and 20th June, 2018. This report compiles the abstracts and the presentation materials in the above conference.

Journal Articles

Sorption behavior of U and Np on zeolite

Ishidera, Takamitsu; Tachi, Yukio; Akagi, Yosuke*; Ashida, Takashi

Progress in Nuclear Science and Technology (Internet), 5, p.221 - 224, 2018/11

In Fukushima Daiichi Nuclear Power Station, radionuclides are removed from contaminated water by the decontamination system using zeolite. In this study, sorption properties of U and Np on zeolite were investigated by batch sorption experiments to obtain fundamental information for predicting the radionuclides inventory. High distribution coefficients were observed for U in the simulated sea water diluted 10 times by deionized water. In contrast, low distribution coefficient of U was observed in simulated sea water. Low distribution coefficients were observed for Np independent of simulated sea water concentration. Batch sorption experiments of U carried out as functions of sodium ion and total inorganic carbon concentration suggested that the distribution coefficient of U was strongly affected by the total inorganic carbon concentration. This result suggests that aqueous species of radionuclides and their sorption behavior need to be considered to estimate the inventory of radionuclides in zeolite.

JAEA Reports

Inspection and repair techniques in reactor vessel of the experimental fast reactor JOYO; Development of devices for retrieving bent MARICO-2 subassembly and completion of retrieval work

Ashida, Takashi; Nakamura, Toshiyuki*; Ito, Hideaki

JAEA-Technology 2017-024, 198 Pages, 2017/11

JAEA-Technology-2017-024.pdf:55.8MB
JAEA-Technology-2017-024-appendix(CD-ROM)-1.zip:298.09MB
JAEA-Technology-2017-024-appendix(CD-ROM)-2.zip:210.77MB

In the experimental fast reactor Joyo, the disconnecting of an irradiation test subassembly MARICO-2 (Material Testing Irradiation Rig with Temperature Control) from its holding mechanism was conducted in May 2007. After the operation, the rotating plug was rotated despite the fact that the test subassembly was not disconnected completely. Consequently, top of wrapper tube of the MARICO-2 subassembly was bent onto the in-vessel storage rack. Since the overhanging part of the subassembly was in the height in which contacts with the upper core structure, it had damaged the bottom surface of the upper core structure. As the result, it was necessary to replace the damaged upper core structure and to retrieve the bent MARICO-2 subassembly for Joyo restart. Retrieval devices for MARICO-2 subassembly consist of a gripper mechanism to lift subassembly together with transfer pot, a guide tube built-in a pantograph mechanism to adjust lifting axis and safety mechanisms to prevent or mitigate falling of MARICO-2 subassembly, a retrieval cask and so on. Design of the retrieval devices have been verified in ex-vessel partial or full-scale mock-up tests and in-vessel function tests. In 2014, MARICO-2 subassembly was successfully retrieved from the reactor vessel by applying these retrieval devices. Then, retrieved subassembly was transported to a hot-cell facility for post-irradiation examinations. Devices have demonstrated expected performance under the actual environmental conditions of a sodium cooled fast reactor. This is a synthetic report about the retrieval work of the deformed and irradiated test subassembly in Joyo. This report includes the detail design and fabrication of the special retrieval device, results of tests for confirmation including the mock-up tests in manufacturer's factory, and results of MARICO-2 retrieval work from the reactor vessel.

JAEA Reports

Proceedings of the Research Conference on Cementitious Composites in Decommissioning and Waste Management (RCWM2017); June 20th and 21st, 2017, Tomioka Town Art&Media Center, Tomioka, Futaba, Fukushima, Japan

Sano, Yuichi; Ashida, Takashi

JAEA-Review 2017-021, 180 Pages, 2017/11

JAEA-Review-2017-021.pdf:86.98MB

Collaborative Laboratories for Advanced Decommissioning Science (CLADS) is responsible to promote international cooperation in the R&D activities on the decommissioning of Fukushima Daiichi Nuclear Power Station and to develop the necessary human resources. CLADS held the Research Conference on Cementitious Composites in Decommissioning and Waste Management (RCWM2017) on 20th and 21st June, 2017. This report compiles the abstracts and the presentation materials in the above conference.

Journal Articles

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

Neutron devices such as neutron detectors, optical devices including supermirror devices and $$^{3}$$He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

Journal Articles

Characterization of rare earth elements (REEs) associated with suspended particles in deep granitic groundwater and their post-closure behavior from a simulated underground facility

Iwatsuki, Teruki; Munemoto, Takashi*; Kubota, Mitsuru*; Hayashida, Kazuki; Kato, Toshihiro*

Applied Geochemistry, 82, p.134 - 145, 2017/05

AA2017-0090.pdf:2.35MB

 Times Cited Count:5 Percentile:34.5(Geochemistry & Geophysics)

This study investigated the behavior of rare earth elements (REEs) associated with suspended particles in deep granitic groundwater and in a sealed drift at a depth of 500 m in the Mizunami Underground Research Laboratory (URL) in Japan. Approximately 10%$$sim$$60% of REEs in groundwater are associated with suspended particles. Carbonate particles in groundwater are most likely derived from in situ precipitation of supersaturated carbonate minerals such as calcite. Thermodynamic calculations show that the dissolved REE carbonate complexes in the closed drift decreased in the drift closure period. These complexes may have been absorbed or co-precipitated within the shotcrete on the drift wall. The usage of cement based materials would generate environmental conditions in which REEs are fundamentally immobile in and around the underground facilities.

JAEA Reports

Hydrochemical investigation at the Mizunami Underground Research Laboratory; Compilation of groundwater chemistry data in the Mizunami group and the Toki granite (fiscal year 2015)

Hayashida, Kazuki; Kato, Toshihiro; Munemoto, Takashi; Aosai, Daisuke*; Inui, Michiharu*; Kubota, Mitsuru; Iwatsuki, Teruki

JAEA-Data/Code 2017-008, 52 Pages, 2017/03

JAEA-Data-Code-2017-008.pdf:3.84MB

Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the effect on excavating and maintenance of underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project in Mizunami, Gifu, Japan. In this report, we compiled data of groundwater chemistry obtained at the MIU in the fiscal year 2015. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling time, sampling method, analytical method) and methodology for quality control are described.

Journal Articles

Radioactive contamination of several materials following the Fukushima Daiichi Nuclear Power Station accident

Koma, Yoshikazu; Shibata, Atsuhiro; Ashida, Takashi

Nuclear Materials and Energy (Internet), 10, p.35 - 41, 2017/01

 Times Cited Count:13 Percentile:86.92(Nuclear Science & Technology)

Due to the accident of Fukushima Daiichi Nuclear Power Station (NPS) of Tokyo Power Electric Co. in 2011, radioactive nuclides were released to environment and heavily contaminated the NPS site itself. Analytical concentration of radionuclides for contaminated materials including the accumulated water, rubble, soil and vegetation which already opened were utilized to discuss contamination behavior of some radionuclides. The concentration ratio of a radionuclide to that of $$^{137}$$Cs was normalized with composition of the damaged reactor fuels referred to as "transport ratio" to investigate elemental behavior. The transport ratio of Sr to rubble and soil compared with which was assumed to be via air was approximately 10$$^{-2}$$ to 10$$^{-3}$$, and the successive transport to the accumulated water was comparable to Cs except for the initial release. Transport of Pu, Am and Cm were scarce relative to Cs regardless of transport process by means of air and water, whereas those of iodine, selenium and tellurium were comparable or greater. Contamination with $$^{3H}$$ and $$^{14}$$C was independent of $$^{137}$$Cs, $$^{90}$$Sr and TRU nuclides and would be a result of different transport process.

Journal Articles

Development of inspection and repair techniques in reactor vessel of experimental fast reactor "Joyo"; Retrieval of the bent test subassembly

Ashida, Takashi; Ito, Hideaki; Miyamoto, Kazuyuki*; Nakamura, Toshiyuki; Koga, Kazuhiro*; Ohara, Norikazu*; Ino, Hiroichi*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 15(4), p.210 - 222, 2016/12

In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of material testing rig named "MARICO-2" had been broken and bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). As the result, for Joyo restart, it was necessary to replace the damaged UCS and to retrieve the bent sub-assembly. This paper describes in-vessel repair techniques performed in the retrieval work of the obstacle inside of the reactor vessel. The devices which were prepared for this work demonstrated expected performance under the environmental conditions of an SFR such as high temperature and radiation dose, and the work was completed in 2014. The successful operation of this retrieval work of the damaged component inside of a reactor vessel will contribute to the development of in-service inspections and repair technics in an SFR.

Journal Articles

Inventory estimation for accident waste generated at the Fukushima Daiichi NPS

Koma, Yoshikazu; Sugiyama, Daisuke*; Ashida, Takashi

Proceedings of International Conference on the Safety of Radioactive Waste Management (Internet), p.153_1 - 153_4, 2016/11

To investigate accident waste management at the Fukushima Daiichi Nuclear Power Station, a methodology of inventory estimation for whole waste including those generated through D&D is indispensable and requires a calculation model. At early stage with insufficient analytical data of waste, a model should be developed by using knowledge of past experience from literature. Uncertainty in estimation shall be decreased based on analytical data available.

Journal Articles

Approaches of selection of adequate conditioning methods for various radioactive wastes in Fukushima Daiichi NPS

Meguro, Yoshihiro; Nakagawa, Akinori; Kato, Jun; Sato, Junya; Nakazawa, Osamu; Ashida, Takashi

Proceedings of International Conference on the Safety of Radioactive Waste Management (Internet), p.139_1 - 139_4, 2016/11

A variety of radioactive wastes have been generated in decommissioning of Fukushima Daiichi Nuclear Power Station. It is necessary to evaluate feasibility of conditioning methods to these wastes, because the majority of such wastes have not been solidified in Japan. The authors investigated an approach for screening of conditioning methods for the Fukushima wastes on the basis of the findings of the existing methods and results of fundamental solidification tests using synthetic Fukushima wastes. Here five solidification methods were selected, and also 13 wastes with different chemical composition are solidified, and characteristics of the solidified form are studied. A screening flow was proposed, and evaluation criteria on each step in the flow was set up. In this presentation a trial result was opened for a waste and improvements of the screening flow found in the trial evaluation was described.

JAEA Reports

Hydrochemical investigation at the Mizunami Underground Research Laboratory; Compilation of groundwater chemistry data in the Mizunami group and the Toki granite (fiscal year 2014)

Hayashida, Kazuki; Munemoto, Takashi; Aosai, Daisuke*; Inui, Michiharu*; Iwatsuki, Teruki

JAEA-Data/Code 2016-001, 64 Pages, 2016/06

JAEA-Data-Code-2016-001.pdf:3.19MB

Japan Atomic Energy Agency has been investigating groundwater chemistry to understand the effect on excavating and maintenance of underground facilities as part of the Mizunami Underground Research Laboratory (MIU) Project in Mizunami, Gifu, Japan. In this report, we compiled data of groundwater chemistry obtained at the MIU in the fiscal year 2014. In terms of ensuring traceability of data, basic information (e.g. sampling location, sampling time, sampling method, analytical method) and methodology for quality control are described.

JAEA Reports

Analysis results of contaminated water and rubbles/soils in Fukushima Daiichi Nuclear Power Station; The Release of FY2014 edition of the analysis results of contaminated water and rubbles/soils

Asami, Makoto; Watahiki, Hiromi; Oi, Takao; Shibata, Atsuhiro; Ashida, Takashi

JAEA-Data/Code 2015-020, 80 Pages, 2015/11

JAEA-Data-Code-2015-020.pdf:45.07MB
JAEA-Data-Code-2015-020-appendix(DVD-ROM).zip:602.44MB

FY2014 edition of the analysis results on contaminated water in the circulating system and on rubbles/soils of Fukushima Daiichi Nuclear Power Station (1F NPS) was compiled. This technical report shows the function of the electronic file of the FY2014 edition of the analysis results on contaminated water and on rubbles/soils and presents the user manual with example and gives the electronic file by appendix CD.

Journal Articles

Development status of the NMR system for the polarized $$^{3}$$He Neutron Spin Filter (NSF) in the MLF at J-PARC

Sakai, Kenji; Oku, Takayuki; Hayashida, Hirotoshi*; Kira, Hiroshi*; Hiroi, Kosuke; Ino, Takashi*; Oyama, Kenji*; Okawara, Manabu*; Kakurai, Kazuhisa; Shinohara, Takenao; et al.

JPS Conference Proceedings (Internet), 8, p.036015_1 - 036015_6, 2015/09

The polarized $$^{3}$$He filter, which polarizes neutrons due to a large neutron absorption cross section of $$^{3}$$He with strong spin selectivity, becomes a convenient neutron spin filter (NSF) because it is operated immediately after its installation in beam lines without any neutron beam adjustments. For realizing such the NSF, a nuclear magnetic resonance (NMR) system is indispensable for monitoring $$^{3}$$He nuclear spin polarization ${it P}$ of the NSF. We have developed the flexible NMR system based on adiabatic fast passage (AFP) and pulse NMR methods by using their complementary features. In comparing with the values of ${it P}$ obtained by neutron transmission measurement at the beam line 10 of the J-PARC, we measured the correlations between the AFP and pulse NMR signals as changing condition of temperature, amplitude and applying period of the radio frequency field for the pulse NMR, and so on. As the results, we confirmed that our system would function enough as the ${it P}$ monitor.

Journal Articles

Experimental fast reactor "JOYO" retrieval for the bent MARICO-2 test subassembly using remote control devices

Koga, Kazuhiro*; Ohara, Norikazu*; Ino, Hiroichi*; Kondo, Katsumi*; Ito, Hideaki; Ashida, Takashi; Nakamura, Toshiyuki

FAPIG, (190), p.3 - 8, 2015/07

no abstracts in English

139 (Records 1-20 displayed on this page)