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Journal Articles

Journal Articles

A New cross section adjustment method of removing systematic errors in fast reactors

Takeda, Toshikazu*; Yokoyama, Kenji; Sugino, Kazuteru

Annals of Nuclear Energy, 109, p.698 - 704, 2017/11

 Times Cited Count:2 Percentile:19.91(Nuclear Science & Technology)

A new cross section adjustment method has been derived in which systematic errors in measured data and calculated results of neutronics characteristics are estimated and removed in the adjustment. Bias factors which are the ratio between measured data and calculated results are used to estimate systematic errors. The difference of the bias factors from unity is caused generally by systematic errors and stochastic errors. Therefore by determining whether the difference is within the total stochastic errors of measurements and calculations, systematic errors are estimated. Since stochastic errors are determined for individual confidence levels, systematic errors are also dependent to the confidence levels. The method has been applied to cross section adjustments using 589 measured data obtained from fast critical assemblies and fast reactors. The adjustments results are compared with those of the conventional adjustment method. Also the effect of the confidence level to the adjusted cross sections is discussed.

Journal Articles

Numerical investigation of the random arrangement effect of coated fuel particles on the criticality of HTTR fuel compact using MCNP6

Ho, H. Q.; Honda, Yuki; Goto, Minoru; Takada, Shoji

Annals of Nuclear Energy, 103, p.114 - 121, 2017/05

 Times Cited Count:8 Percentile:61.68(Nuclear Science & Technology)

Journal Articles

Benchmark study on realized random packing model for coated fuel particles of HTTR using MCNP6

Ho, H. Q.; Morita, Keisuke*; Honda, Yuki; Fujimoto, Nozomu*; Takada, Shoji

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04

Journal Articles

JAEA's contribution for R&D and human resource development on implementing IAEA safeguards

Naoi, Yosuke; Oda, Tetsuzo; Tomikawa, Hirofumi

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 58(9), p.536 - 541, 2016/09

Japan has been promoting nuclear energy research and development, and the use of nuclear energy for only peaceful purposes in accordance with Atomic Energy Basic Acts enacted in 1955. In order to ensure limited to their peaceful utilization, it has been performing a nuclear material accountancy and reporting it based on bilateral nuclear agreement (Japan and the United States, Japan and France, Japan and Canada and so on) before concluding the comprehensive safeguards agreement with the IAEA. After the conclusion of that in 1977, the Japanese national law had been revised. The nuclear material accountancy and its reports to the IAEA have been implemented based on the revised law. In 1999, Japan ratified the additional protocol. Then it has been responding a new obligation in the additional protocol. The correctness and completeness of the declaration of nuclear activities in Japan have been verified by the IAEA, and then the "broader conclusion" was given to Japan in 2004. There indicates no diversion or undeclared nuclear activities in Japan. Since then Japan has been obtaining the "broader conclusion" every year. In this report we will report the JAEA's contribution to the IAEA safeguards on technical research and development and human resource development.

Journal Articles

Development and operation of the JAERI superconducting energy recovery linacs

Minehara, Eisuke

Nuclear Instruments and Methods in Physics Research A, 557(1), p.16 - 22, 2006/02

 Times Cited Count:11 Percentile:60.35(Instruments & Instrumentation)

The JAERI FEL facility at Tokai, Ibaraki, Japan has been well known one of the two existing and operating superconducting energy recovery linacs together with one more of JLAB (Jefferson national accelerator facility) FEL facility at Newport News, Virginia, U.S.A. We have independently and successfully developed one of the most advanced and newest accelerator technologies named "superconducting energy recovery linacs (ERLs)" and the application technologies using ERLs in future. We plan to report the current high power FEL upgrade program research, stress corrosion cracking prevention technology research, large current and high brightness photoelectron gun research of negative-electron affinity (NEA) photocathode and NEA electron-excitation cathode as the most important elemental technology in realizing many powerful ERLs.

Journal Articles

Experimental verification of velocity bunching via shot-by-shot measurement at S-band photoinjector and linac

Iijima, Hokuto; Uesaka, Mitsuru*; Sakamoto, Fumito*; Ueda, Toru*; Kumagai, Noritaka*; Serafini, L.*

Japanese Journal of Applied Physics, Part 1, 44(7A), p.5249 - 5253, 2005/01

 Times Cited Count:8 Percentile:32.22(Physics, Applied)

We represent an experimental verification of a bunch compression method named "velocity bunching". The velocity bunching based on the rectilinear compression uses a traveling wave accelerating tube as a compressor. The experiment was performed by an S-band photoinjector and a linac at Nuclear Engineering Research Laboratory, University of Tokyo. The shot-by-shot bunch length was measured to be 0.5 $$pm$$ 0.1 ps (rms) in average by the femtosecond streak camera for a bunch charge of 1 nC. The experimental result is in good agreement with PARMELA simulations.

Journal Articles

Fabrication and characterization of C-doped anatase TiO$$_{2}$$ photocatalysts

Choi, Y.; Umebayashi, Tsutomu; Yoshikawa, Masahito

Journal of Materials Science, 39(5), p.1837 - 1839, 2004/03

 Times Cited Count:224 Percentile:97.87(Materials Science, Multidisciplinary)

Carbon (C)-doped anatase TiO$$_{2}$$ photocatalysts have been prepared by the oxidative annealing of TiC powders at 623 K for 50-100 hrs. From XRD and XPS analysis, it is clear that C is incorporated into O site of the TiO$$_{2}$$ lattice. Diffuse reflectance spectroscopy (DRS) showed that the optical absorption edge of the C-doped anatase TiO$$_{2}$$ shifted to lower energy compared with that of pure anatase TiO$$_{2}$$. The decomposition of methylene blue (MB) adsorbed on the C-doped sample was observed under a visible light range of 420-500 nm. We conclude that substitution of C for O in the TiO$$_{2}$$ leads to a photocatalytic decomposition of MB under visible light irradiation.

Journal Articles

Fabrication of TiO$$_{2}$$ photocatalysts by oxidative annealing of TiC

Choi, Y.; Umebayashi, Tsutomu; Yamamoto, Shunya; Tanaka, Shigeru

Journal of Materials Science Letters, 22(17), p.1209 - 1211, 2003/09

 Times Cited Count:46 Percentile:78.62(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Current point formation and magnetic reconnection process in nonlinearly destabilized double tearing modes

Ishii, Yasutomo; Azumi, Masafumi; Kishimoto, Yasuaki

Physics of Plasmas, 10(9), p.3512 - 3520, 2003/09

 Times Cited Count:11 Percentile:37.16(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

X-ray-induced ion desorption from solid surfaces

Baba, Yuji

Trends in Vacuum Science & Technology, Vol.5, p.45 - 74, 2002/10

This article reviews recent works on the ion desorption from solid surfaces induced by the irradiation of soft X-rays ranging from 100 eV to 3 keV. The data presented here are focused on the positive ion desorption from adsorbed, condensed, and solid molecules following the core-level excitations. The element-specific and site-specific fragment-ion desorptions are clearly realized, when we tune the photon energy at the core-to-valence resonance regions. The specificity of the ion desorption more clearly shows up following the deep-core excitations, i.e., 1s$$rightarrow$$4p resonant excitations in third-row elements, rather than the shallow-core excitations. Since the main decay channels after the core-level excitation are the Auger transitions, the Auger decay spectra excited by the photons around the core-level thresholds are also presented for some of the adsorbed systems. The mechanism of the observed highly specific ion desorption is discussed on the basis of the photon-energy dependencies of the electron and ion yields and the analysis of the Auger decay spectra.

Journal Articles

Preparation of epitaxial TiO$$_{2}$$ films by PLD for photocatalyst applications

Yamaki, Tetsuya; Sumita, Taishi; Yamamoto, Shunya; Miyashita, Atsumi

Journal of Crystal Growth, 237-239(Part1), p.574 - 579, 2002/04

Pulsed laser deposition (PLD) with a KrF excimer laser was used to prepare epitaxial TiO$$_{2}$$ films on a (0001) sapphire substrate. The crystalline structure and surface morphology of the films were then investigated as a function of the laser power density in the PLD. X-ray diffraction and Raman spectroscopy results showed that the films were composed of the (100) oriented rutile phase with a small amount of the (001) oriented anatase. The anatase-to-rutile ratio in such phase-mixed films was controlled by the laser power; the ratio increased as the power density decreased. From atomic force microscopy observations, the film deposited at the lowest power was found to have a rough surface consisting of coarse grains. This film exhibited the best photocatalytic performance during the decomposition of the organic dyes possibly due to the maximum relative content of anatase and the large surface area.

Journal Articles

Relativistic effects on chaos; Loss mechanism of runaway electrons in a tokamak

Tokuda, Shinji; Higuchi, Takatoshi*; Suzuki, Noriyuki*

Purazuma, Kaku Yugo Gakkai-Shi, 77(12), p.1180 - 1220, 2001/12

no abstracts in English

Journal Articles

Preparation of TiO$$_{2}$$-anatase film on Si(001) substrate with TiN and SrTiO$$_{3}$$ as buffer layers

Sugiharuto; Yamamoto, Shunya; Sumita, Taishi; Miyashita, Atsumi

Journal of Physics; Condensed Matter, 13(13), p.2875 - 2881, 2001/04

 Times Cited Count:15 Percentile:61.89(Physics, Condensed Matter)

An epitaxial TiO$$_{2}$$-anatase thin film was grown on the Si(001) substrate with SrTiO$$_{3}$$/TiN as the buffer layers by pulsed laser deposition technique under an oxygen gas supply. The characterization of the epitaxial TiO$$_{2}$$-anatase film was performed using the X-ray diffraction method. The crystallographic relationships between the TiO$$_{2}$$-anatase film and SrTiO$$_{3}$$/TiN buffer layers were analyzed by the $$theta$$-2$$theta$$ scan and pole figure measurement. The growth direction of the films was determined as $$rm TiO_{2}langle 001rangle$$ / $$rm SrTiO_{3}langle 001rangle$$ / $$rm TiNlangle 001rangle$$ / $$rm Silangle 001rangle$$ and their in-plane relationship $$rm TiO_{2}{110}$$ // $$rm SrTiO_{3}{100}$$ // $$rm TiN{100}$$ // $$rm Si{100}$$. The crystalline quality of TiO$$_{2}$$-anatase was examined by the rocking curve analysis. The composition of the thin film packaging was characterized by Rutherford backscattering spectrometry (RBS) using 2.0 MeV $$^{4}$$He beam.

Journal Articles

Progress towards the establishment of integrated safeguards in Japan

Naito, Kaoru; Ogawa, Tsuyoshi*; Osabe, Takeshi*

Proceedings of 42nd INMM Annual Meeting, 12 Pages, 2001/00

no abstracts in English

JAEA Reports

Evaluation of soluble organic compounds generated by radiological degradation of asphalt

Fukumoto, Masahiro; Nishikawa, Yoshiaki*; Kagawa, Akio; Kawamura, Kazuhiro

JNC TN8400 2001-002, 23 Pages, 2000/12

JNC-TN8400-2001-002.pdf:0.55MB

The soluble organic compounds generated by radiological degradation of asphalt ($$gamma$$ ray) were confirmed as a part of influence of the bituminized waste degradation in the TRU waste repository. Especially, the influence of the nitrate was focused on. As a result, the concentration of the soluble organic compounds generated by radiological degradation of asphalt (10MGy, $$gamma$$ ray which is correspond to absorbed dose of asphalt for 1,000,000 years) were lower (each formic acid : about 50mg/dm$$^{3}$$, acetic acid : about 30mg/dm$$^{3}$$ and oxalic acid : about 2mg/dm$$^{3}$$) than that of the formic acid, the acetic acid and the oxalic acid which Valcke et al. had shown (the influence of the organic at the solubility examination which uses Pu and Am). Moreover, the change in the concentration of TOC and the soluble organic compounds (formic acid, acetic acid and oxalic acid) is little under the existence of nitrate ion. That is, the formic acid and acetic acid which can be organic ligands were generated little by oxidative decomposition of asphalt in the process that nitrate ion becomes nitrite ion by radiation. The influence of the soluble organic compounds by the radiological degradation of the asphalt ($$gamma$$ ray) on adsorption and solubility by the complexation of radionuclides in the performance assessment can be limited.

JAEA Reports

Organic acid dissolving in groundwater in the Mobara gas field

JNC TN8400 2000-030, 17 Pages, 2000/12

JNC-TN8400-2000-030.pdf:0.44MB

As a representative of natural marine groundwater, the author selected pumped water from a Quaternary sedimentary aquifer of the Mobara gas-field in Japan and measured the concentration of total organic carbon (TOC) and of organic acid anions (formic, acetic, lactic, succinic, humic, fulvic, propionic, valeric and butyric acids). The concentration of TOC ranged from 22$$pm$$1 to 24$$pm$$0mg/L. As organic acid anions, only succinic and fulvic acids were detected and each concentration was given to be from 5.8$$pm$$ 0.5 to 8.3$$pm$$0.3 and from 3.3$$pm$$0.2 to 3.5$$pm$$0.2mg/L, respectively. By consideration of the temperature and the [SO$$_{4}$$$$^{2-}$$] of the groundwater, it is inferred that the organic acid has been significantly decomposed by activities of microbes, such as the fermentation process, CH$$_{3}$$COO$$^{-}$$ + H$$_{2}$$O = HCO$$_{3}$$$$^{-}$$ + CH$$_{4}$$.

Journal Articles

Radiobiogical characterization of epithermal and mixed thermal-epithermal beams at JRR-4

Yamamoto, Tetsuya*; Matsumura, Akira*; Shibata, Yasushi*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Hori, Naohiko; Torii, Yoshiya; Ono, Koji*; Kobayashi, Toru*; et al.

Proceedings of 9th International Symposium on Neutron Capture Therapy for Cancer, p.205 - 206, 2000/10

no abstracts in English

Journal Articles

Site-specific fragmentation of acetone adsorbates on Si(100) in the carbon 1s absorption edge

Sekiguchi, Tetsuhiro; Sekiguchi, Hiromi*; Baba, Yuji

Surface Science, 454-456, p.363 - 368, 2000/05

 Times Cited Count:23 Percentile:72.49(Chemistry, Physical)

no abstracts in English

Journal Articles

A Trial of strengthened IAEA safeguards at JAERI, Tokai, Japan

Shimizu, Kenichi

Regional Training Course on National Safeguards Systems (CD-ROM), p.5 - 0, 2000/04

no abstracts in English

53 (Records 1-20 displayed on this page)