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Journal Articles

Development on rubber bearings for sodium-cooled fast reactor, 3; Ultimate properties of a half scale thick rubber bearings based on breaking test

Fukasawa, Tsuyoshi*; Okamura, Shigeki*; Yamamoto, Tomohiko; Kawasaki, Nobuchika; Hirotani, Tsutomu*; Moriizumi, Eriko*; Sakurai, Yu*; Masaki, Nobuo*

Proceedings of 2016 ASME Pressure Vessels and Piping Conference (PVP 2016) (Internet), 10 Pages, 2016/07

Half-scale thick rubber bearing to investigate ultimate properties application for a Sodium-cooled-Fast-Reactor. The fundamental restoring-force characteristics of the thick rubber bearings has been already cleared through the static loading tests using a half-scale thick rubber bearing, 800 mm in diameter. However, variations of the restoring force characteristics and ultimate properties have not been obtained yet. The purpose of this paper is to indicate the variation of the stiffness and damping ratio concerning restoring force characteristics and the breaking strain or stress as ultimate properties through static loading tests using the half-scale thick rubber bearings.

Journal Articles

Development of superconducting proton linac for ADS

Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Namekawa, Yuya*; Suzuki, Hiroyuki*; Ueno, Tomoaki*; Noguchi, Shuichi*; Kako, Eiji*; Ouchi, Norihito*; et al.

Proceedings of 4th International Workshop on the Utilisation and Reliability of High Power Proton Accelerators, p.175 - 183, 2005/11

no abstracts in English

JAEA Reports

Research on Environment Monitoring of Radiation Emergency

Ito, Yoshifumi*; Endo, Nobuyuki*; Otani, Nobuo*

JNC TJ4440 2004-005, 430 Pages, 2005/03

JNC-TJ4440-2004-005.pdf:5.92MB

no abstracts in English

JAEA Reports

None

Kume, Kyo*; Otani, Nobuo*

JNC TJ4440 2004-003, 287 Pages, 2005/03

JNC-TJ4440-2004-003.pdf:26.52MB

no abstracts in English

Journal Articles

Development of the neutron detection system for the measurement from thermal region to fast region

Kume, Kyo*; Otani, Nobuo*; Tamagawa, Yoichi*

Heisei-16-Nendo Zaidan Hojin Wakasawan Enerugi Kenkyu Senta Kenkyu Seika Hokokushu, 7, p.29 - 32, 2005/00

The neutron detection systems for the measurement covering wide energy range from thermal to fast region has been successively developed. The main part of this system is made of organic scintillators (both liquid and plastic) with doped 10B, so that it should be sensitive to thermal neutrons with (n,$$alpha$$) reaction while it could detect signals during degrading fast neutrons within the scintillator. This principle was verified. Also another system made of inorganic crystals was verified to see the capability to be used as a neutron detector.

JAEA Reports

Development of the Environmental Neutron Detection System

Kume, Kyo*; Otani, Nobuo*

JNC TJ4440 2003-007, 312 Pages, 2004/03

JNC-TJ4440-2003-007.pdf:42.33MB

Environmental neutron detection system is proposed. The main goal of this system was set to detect fast and thermal neutrons with the identical detector setup without degraders. A detector setuup for thermal neutron counting in prebious years, was developed first. Feasible study of this detector system for fast neutron counting was done, with help of Monte Carlo simulation and analysis of experiments with both a neutron source and neutron beam at an accelerator facility. In addition, B doped plastic intillator was studied for measurement of environmental neutrons. This was done through experiments with an Am-Be neutron source, with help of Monte Carlo simulation. In the meantime, possibility of the use of inorganic scintillators in neutron counting was verified, to solve the problems occuring at the long term use of the organic liquid scintillators. The detectors checked were BGO, GSO, and Nal. BGO was shown that it has little possibility for use at neutron measurement, while GSO and Nal were shown that these detectors have trivial sensitivity in neutron measurement.

JAEA Reports

Research on Environment Monitoring of Radiation Emergency

Ito, Yoshifumi*; Endo, Nobuyuki*; Otani, Nobuo*

JNC TJ4440 2003-006, 408 Pages, 2004/03

JNC-TJ4440-2003-006.pdf:11.8MB

In a case of nuclear accident at nuclear facililties, strong radiations such as g-rays and neutrons might radiate at a bust in the initial stage. For the establishment of dose estimation system for such accidents, the experiments were done using the 200 MeV proton beam accelerated by synchrotron in the W-MAST. DC current mode neutron detection sysstem was tested for hegh dose neutron irradiation, where ther system was composed by NE213 scintillate, photomultiplier and pre-amp. The following results were obtained: (1) When one fast neutron was injected into NE213, the shape of pre-amp output signal wa Gaussian type with the full width of half maximum of -40ns. (2) Linear relation between the radiation intensity of neutron and the proton current was obtained in the detection system. The neutron more than 25 Mcps can be detected using this detection system with the DC current mode. In order to establish the method of the dose of radioactivity measuring using the electron spin resonance (ESR) technique, stable free-radicals generated in the tooth enamel by gamma-ray irradiation as basis research was measured with ESR equipment, precise signal analysis was performed, and the dose evaluation characteristic of having purpose at higher sensitivity was investigated. Moreover, the relationship between the dose of radioactivity and ESR signal intensity of free-radical species which were generated by X-ray irradiation, and damping behavior of the signal were evaluated about seven kinds of analogous inorganic compound to tooth enamel.

Journal Articles

R&D status of superconducting proton linear accelerator for ADS at JAERI

Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 6 Pages, 2003/04

no abstracts in English

JAEA Reports

None

Ito, Yoshifumi*; Kume, Kyo*; Otani, Nobuo*

JNC TJ4440 2003-002, 284 Pages, 2003/03

JNC-TJ4440-2003-002.pdf:11.68MB

no abstracts in English

Journal Articles

Cold test of 600MHz superconducting cryomodule for high intensity proton linac

Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu*; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.

Proceedings of 21st International Linear Accelerator Conference, p.488 - 490, 2003/00

Development of a superconducting proton linac is in progress in collaboration with KEK. In order to demonstrate cavity performance and to study stable accelerating field in a pulsed operation, a 600MHz superconducting cryomodule has been fabricated. The cryomodule includes two 5-cell superconducting cavities of $$beta$$=0.6 and is designed to perform 2K operation. Cold tests of the cryomodule have been performed at the temperature of 4K and 2K. In the tests, heat leak to the cavities, loaded quality factors, tuning sensitivities, frequency shifts against helium vessel pressure and Lorentz force detuning of the cavities were measured. Most of the measured data agreed with their design values, except for the heat leak and the Lorentz force detuning. As the preliminary horizontal test of the cryomodule, high power RF test has been also performed, where the surface peak fields of 10 and 16 MV/m were achieved in CW and pulsed operation, respectively. Now, the optimization of the RF control system is in progress to demonstrate stable accelerating field in a pulsed operation.

JAEA Reports

Research on Environment Monitoring of Radiation Emergency

Ito, Yoshifumi*; Otani, Nobuo*

JNC TJ4400 2002-001, 150 Pages, 2002/03

JNC-TJ4400-2002-001.pdf:5.71MB

None

Journal Articles

Numerical Validation of the Theory of Coupled Reactors for the Heavy Water Critical Assembly DCA

Nishihara, Kenji*; Kobayashi, Keisuke*; Otani, Nobuo

Journal of Nuclear Science and Technology, 36(3), p.265 - 272, 1999/00

JAEA Reports

Application of difference filter to Feynman-$$alpha$$ analysis

Mori, Tomoaki; Otani, Nobuo

PNC TN9410 97-095, 44 Pages, 1997/11

PNC-TN9410-97-095.pdf:0.99MB

The Feynman-$$alpha$$ method has been developed for monitoring sub-criticality in nuclear fuel facilities. It is difficult to apply the Feynman-$$alpha$$ method which estimates statistical variation of the number of neutron counts per unit time, to the system in transient condition such that the averaged neutron flux varies with time. In the application of Feynman-$$alpha$$ method to such system, it is suggested to remove the averaged variation of neutron flux from neutron count data by the use of the difference filter. In this study, we applied the difference filter to reactor noise data at sub-criticality near to criticality, where the prompt decay constant was difficult to estimate due to the large effect of delayed neutron. With the difference filter, accurate prompt decay constants for effective multiplication factors from 0.999 to 0.994 were obtained by Feynman-$$alpha$$ method. It was cleared that the difference filter is effective to estimate accurate prompt decay constant, so that there is the prospect to be able to apply Feynman-$$alpha$$ method having the difference filter to the system in the transient condition.

Journal Articles

Axial Dependence of Partial Void Reactivity in a Light Water-Cooled, Heavy Water-Moderated, Pressure-Tube Reactor

Aihara, Nagafumi; Fukumura, Nobuo; Kadotani, Hiroyuki*; Hachiya, Yuki

Nuclear Science and Engineering, 109, p.158 - 170, 1991/00

 Times Cited Count:4 Percentile:48.41(Nuclear Science & Technology)

None

JAEA Reports

Void reactivity analysis on high temperature fast reactor

Otani, Nobuo*

PNC TN9410 90-083, 70 Pages, 1990/07

PNC-TN9410-90-083.pdf:1.48MB

Core physics was studied on the High Temperature Fast Reactor (HTFR) whose prime objective is to produce hydrogen. Core of HTFR consits of nitride or oxide fuel, and thermal power of a commercial HTFR is assumed to be 300 to 400 MWt. The analysis in this report aims at the core design having negative or small positive void reactivity from view point to attain safety if the reactors, The method of decreasing sodium void reactivity coefficient was to increase neutron leakage through the large surface area of the core by adopting its shape of a pan cake (core height/core diameter=1/2 to 1/3). Result of the analysis revealed that, total void coefficients is negative for all cases analyzed with U fuel. However almost all the cases analyzed had positive void reactivity coefficients for MOX fuel. Burn-up calculation was peformed for U fuel core. Calculational results showed that the excess reactivity of about 5% was necessary to compensate reactivity decrease due to the burn-up during a year. The above calculations were performed using the CITATION code.

JAEA Reports

Shielding analysis system for fast breeder reactors

Otani, Nobuo*

PNC TN9410 90-030, 35 Pages, 1990/03

PNC-TN9410-90-030.pdf:1.83MB

Shielding Analysis System for Fast Breeder Reactors, which has been developed in Power Reactor & Nuclear Fuel Development Corporation, is summarized. The system has been applied to the analyses of the shielding characteristics of fast breeder reactors, and also applied to the analyses of the experiments for the FBR shielding. The system includes the nuclear data files, which describes the interactions between radiations and materials, and the computer codes, which handle the nuclear data and also calculate teh radiation distributions. Each file or code has been developed in various laboratories in various coutries. We have organized them into the system, and have made assessment by applying the system to the shielding designs and experiment analyses. This system was first established in the activities of "JOYO" shielding data analysis. Since that, the system has been applied to the analyses of the Benchmark experiments, and also to the shielding design calculations of "MONJU" and future reactors. This report summarizes the system constitutions, experiences of applications, and the items of future developments.

JAEA Reports

Characteristics of small reactor core for transportable reactor

Otani, Nobuo*; *; *; Haga, Kazuo*

PNC TN9410 89-145, 98 Pages, 1989/10

PNC-TN9410-89-145.pdf:3.44MB

Core physics of small reactor was examined as a part of conceptual design study of space reactor which is an application of transportable reactor. The design requirements were a fast spectrum reactor using nitride fuel and lithium coolant. Firstly, characteristics of typical uranium core and plutonium core was compared by means of one-dimensional calculation using simple sphere model. Followings were revealed from the comparison of both calculation results. (1)Reactivity loss of uranium core in ten years is smaller than that of plutonium core. (2)Shorter lifetime of plutonium core is due to $$beta$$ decay of Pu-241. Hence, plutonium core must be designed to compensate higher fuel degradation. (3)Installation of thermal neutron absorber between core and reflector region is effective to extend lifetime of plutonium core. Secondly, study to optimize the design of enriched uranium core was performed as a parameter of core configuration, fuel composition and core size from the point of reactivity adjustment. Attention was focused on criticality of fresh core, reactivity degradation, sub-criticality and reactor shut down margin. The results showed that some safety margin can be obtained although it was less than that objected. A 3-dimensional Monte Carlo code was partly used in the analysis. It was revealed that a more superior code in simulating core configuration is necessary.

JAEA Reports

None

*; *; Otani, Nobuo*; ; *; *; *

PNC TN9410 89-144, 132 Pages, 1989/10

PNC-TN9410-89-144.pdf:3.47MB

None

JAEA Reports

Two-dimensional radiation transport calculations for "MONJU" shielding design

Otani, Nobuo*; *; *

PNC TN241 84-13, 679 Pages, 1984/12

PNC-TN241-84-13.pdf:15.34MB

Numerical results of radiation distribution in the plant of Prototype Fast Breeder Reactor "MONJU" are presented. Calculations were performed for the shielding design of "MONJU" by the two-dimensional discrete ordinate radiation transport code "DOT 3.5". For estimating MONJU shielding design parameters. 19 radiation distributions from the core to the IHX and pump room of the primary coolant system were calculated, using reactor core fissions as the source. Numerical data in this report are nominal computational results by the DOT 3.5 code and shielding design judgements are not included. The report is summarized for reference for shielding design calculations for future FBR plants.

JAEA Reports

Radiation attenuation in materials

Otani, Nobuo*; *; *

PNC TN241 84-02, 512 Pages, 1984/03

PNC-TN241-84-02.pdf:11.18MB

Neutron and neutron-induced gamma-ray flux attenuations have been estimated in various materials. Fluxes were obtained by one-dimensional transport code, ANISN-W(PNC), with nuclear group constants by RADHEAT-V3 system. Figures and tables representing attenuations in materials are given for fast, intermediate, thermal and total neutron fluxes, secondary gamma-ray flux, neutron does rate, and secondary gamma-ray does rate. Effects of selections of calculational conditions and/or nuclear group constants were also investigated for these radiation transport calculations. Data given in this report will be useful for the rough evaluation of shielding characteristics of structures in FBR plants.

22 (Records 1-20 displayed on this page)