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Journal Articles

Atmospheric modeling of $$^{137}$$Cs plumes from the Fukushima Daiichi Nuclear Power Plant; Evaluation of the model intercomparison data of the Science Council of Japan

Kitayama, Kyo*; Morino, Yu*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.

Journal of Geophysical Research; Atmospheres, 123(14), p.7754 - 7770, 2018/07

 Times Cited Count:17 Percentile:76.82(Meteorology & Atmospheric Sciences)

We compared seven atmospheric transport model results for $$^{137}$$Cs released during the Fukushima Daiichi Nuclear Power Plant accident. All the results had been submitted for a model intercomparison project of the Science Council of Japan in 2014. We assessed model performance by comparing model results with observed hourly atmospheric concentrations of $$^{137}$$Cs, focusing on nine plumes over the Tohoku and Kanto regions. The results showed that model performance for $$^{137}$$Cs concentrations was highly variable among models and plumes. We also assessed model performance for accumulated $$^{137}$$Cs deposition. Simulated areas of high deposition were consistent with the plume pathways, though the models that best simulated $$^{137}$$Cs concentrations were different from those that best simulated deposition. The ensemble mean of all models consistently reproduced $$^{137}$$Cs concentrations and deposition well, suggesting that use of a multimodel ensemble results in more effective and consistent model performance.

Journal Articles

Control blade degradation test under temperature gradient in steam atmosphere

Shibata, Hiroki; Tokushima, Kazuyuki; Sakamoto, Kan*; Kurata, Masaki

Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.1033 - 1042, 2016/09

To understand the degradation process of control blade channel, control blade degradation tests using sim-materials were performed under various atmospheres with the temperature increase and temperature gradient conditions. In the steam atmosphere with a flow rate of 0.0125 g/s/rod, control blade, channel box, and fuel rods were degraded, especially at the upper part of the test piece, which was similar to that observed in argon atmosphere test. However, the observed degradation was rather different at a flow rate of 0.0417 g/s/rod. At the upper part of the test piece, only the control blade was degraded preferentially and did not react with channel box wall. In contrast, the eutectic reaction of S.S./B$$_{4}$$C-melt and Zry occurred at the lower part. These observations suggested the existence of a threshold condition for the control rod degradation between 0.0125 and 0.0417 g/s/rod which is significantly affected by the thickness of the oxide layer on Zry.

Journal Articles

Detailed deposition density maps constructed by large-scale soil sampling for $$gamma$$-ray emitting radioactive nuclides from the Fukushima Dai-ichi Nuclear Power Plant accident

Saito, Kimiaki; Tanihata, Isao*; Fujiwara, Mamoru; Saito, Takashi*; Shimoura, Susumu*; Otsuka, Takaharu*; Onda, Yuichi*; Hoshi, Masaharu*; Ikeuchi, Yoshihiro*; Takahashi, Fumiaki; et al.

Journal of Environmental Radioactivity, 139, p.308 - 319, 2015/01

 Times Cited Count:191 Percentile:99.23(Environmental Sciences)

Journal Articles

Liquefaction interaction between oxidized Zircaloy and other fuel assembly components of BWR in the early stage of fuel assembly degradation

Tokushima, Kazuyuki; Shibata, Hiroki; Kurata, Masaki; Sawada, Akihiko*; Sakamoto, Kan*

Annual Topical Meeting on Reactor Fuel Performance (TopFuel 2015), Conference Proceedings, Poster (Internet), p.478 - 485, 2015/00

Two type tests were performed to examine the prevention effect of the oxide layers to liquefaction interaction between Zircaloy and core component materials. The oxide layer of Zircaloy was clearly confirmed to prevent the liquefaction interaction under the temperature of melting point of stainless steel even if the oxide layer on Zircaloy of approximately 30 micro meters, which is thinner than it is predicted to be formed under typical accident condition. The oxide layers were able to be formed even in the region where the gas flow is significantly limited by narrow arrangement. Although the oxide layers at the inner position of upper end plug was hard to form, the prevention effect of the oxide layers was sufficiently observed. The axial variation of the thickness of the oxide layers was observed. It suggested that variation of partial pressure of H$$_{2}$$O should be considered to evaluate the growth rate of the oxide layers for detail.

Journal Articles

Shielding study at the Fukui Prefectural Hospital Proton Therapy Center

Satoh, Daiki; Maeda, Yoshikazu*; Tameshige, Yuji*; Nakashima, Hiroshi; Shibata, Tokushi*; Endo, Akira; Tsuda, Shuichi; Sasaki, Makoto*; Maekawa, Motokazu*; Shimizu, Yasuhiro*; et al.

Journal of Nuclear Science and Technology, 49(11), p.1097 - 1109, 2012/11

 Times Cited Count:10 Percentile:65.97(Nuclear Science & Technology)

At the Fukui Prefectural Hospital Proton Therapy Center, neutron doses behind concrete shields and at maze have been measured by using radiation monitors, DARWIN, Wendi-2, a rem meter, and solid state nuclear track detectors. The measured data were compared with the estimations by analytical models and Monte Carlo code PHITS. The analytical model with the parameters employed in shielding design of the facility gave considerably larger estimates than the measured data. This means that the facility was designed with an enough safety margin. The calculation results of PHITS were less than those of the analytical model, and were about 3 times larger than the measured data. From the view point of a safety policy with conservative estimation for shielding design, Monte Carlo simulation is a better tool for estimating radiation safety at accelerator-based proton treatment facilities.

Journal Articles

New utilization and promotion of RI

Enomoto, Shuichi*; Kawamura, Hiroshi; Shirakawa, Yoshiyuki*; Nakanishi, Tomoko*; Nakamura, Kayoko*; Yano, Tsuneo*; Ido, Tatsuo*; Shibata, Tokushi

Isotope News, (657), p.2 - 11, 2009/01

The view of the future and the necessity of the system construction such as supply systems were shown about production of the medical diagnostics $$^{99}$$Mo and the silicon semiconductor on JMTR.

Journal Articles

Measurements of double-differential neutron-production cross-sections for the $$^{9}$$Be(p,xn) and $$^{9}$$Be(d,xn) reactions at 10 MeV

Iwamoto, Yosuke; Sakamoto, Yukio; Matsuda, Norihiro; Nakane, Yoshihiro; Ochiai, Kentaro; Kaneko, Hirohisa; Niita, Koji*; Shibata, Tokushi; Nakashima, Hiroshi

Nuclear Instruments and Methods in Physics Research A, 598(3), p.687 - 695, 2009/01

 Times Cited Count:19 Percentile:78.17(Instruments & Instrumentation)

Double-differential neutron-production cross-sections of a thin beryllium target bombarded with 10 MeV protons and deuterons were measured. Neutron energy spectra in the range above 1.8 MeV were obtained by a time-of-flight method at angles of 15, 30, 45, 60, 75, 90 and 120 degrees. Monte Carlo calculations with the PHITS code were performed using the evaluated nuclear data files ENDF/B-VII, the Bertini/GEM model and the JQMD/GEM model, and compared with the experimental results. It was found that the calculated results using ENDF/B-VII and Bertini/GEM for the $$^{9}$$Be(p,xn) reaction and JQMD/GEM for the $$^{9}$$Be(d,xn) reaction roughly agreed with the experimental results.

Journal Articles

Utilization of radiation in industrial, agricultural and medical fields and its perspective

Shibata, Tokushi

Nihon Butsuri Gakkai-Shi, 63(4), p.257 - 264, 2008/04

The current status for the utilization of radiation in Japan was given from the view point of the economic scale. The topics which will be developed in near future such as lithography, radiation processing, radiation analysis in the industry, mutation breeding, sterile insect technique, food irradiation in agriculture, and radiation diagnosis, radiation therapy in medical field were presented. The important techniques for the further development of utilization of radiation will be the techniques related to the fabrication of semiconductor, developments of small accelerators and compact neutron generators.

Journal Articles

A Visual apparatus for cosmic-rays "spark chamber"

Shibata, Tokushi

Isotope News, (630), p.21 - 26, 2006/10

An explanation from the view point of educational experimental apparatus on the process of the development of a spark chamber, a hodoscope chamber, a chamber for demonstration, and a handmade spark chamber is presented.

Journal Articles

Fast neutron fluence of the Hiroshima atomic bomb

Shibata, Tokushi

Hoshasen, 32(3), p.156 - 166, 2006/07

no abstracts in English

Journal Articles

Radiation shielding study for the J-PARC project

Nakashima, Hiroshi; Shibata, Tokushi; Nakane, Yoshihiro; Masukawa, Fumihiro; Matsuda, Norihiro; Iwamoto, Yosuke; Hirayama, Hideo*; Suzuki, Takenori*; Miura, Taichi*; Numajiri, Masaharu*; et al.

Proceedings of 14th Biennial Topical Meeting of the ANS Radiation Protection and Shielding Division (CD-ROM), p.267 - 282, 2006/00

no abstracts in English

Journal Articles

Radiation safety design for the J-PARC project

Nakashima, Hiroshi; Nakane, Yoshihiro; Masukawa, Fumihiro; Matsuda, Norihiro; Oguri, Tomomi*; Nakano, Hideo*; Sasamoto, Nobuo*; Shibata, Tokushi*; Suzuki, Takenori*; Miura, Taichi*; et al.

Radiation Protection Dosimetry, 115(1-4), p.564 - 568, 2005/12

 Times Cited Count:7 Percentile:47.08(Environmental Sciences)

The High Intensity Proton Accelerator Project, named as J-PARC, is in progress, aiming at studies on the latest basic science and the advancing nuclear technology. In the project, the high-energy proton accelerator complex of the world highest intensity is under construction. In order to establish a reasonable shielding design, both simplified and detailed design methods were used in the shielding design of J-PARC. This paper reviews the present status of the radiation safety design study for J-PARC.

Journal Articles

Status on shielding design study for the high-intensity proton accelerator facility

Sasamoto, Nobuo; Nakashima, Hiroshi; Hirayama, Hideo*; Shibata, Tokushi*

Journal of Nuclear Science and Technology, 39(Suppl.2), p.1264 - 1267, 2002/08

no abstracts in English

Journal Articles

Study of cross section measurement methods using the self-TOF high energy neutron detector

Sasaki, Michiya*; Nunomiya, Tomoya*; Nakamura, Takashi*; Nakao, Noriaki*; Shibata, Tokushi*; Nakane, Yoshihiro; Tanaka, Susumu

JAERI-Review 2000-024, TIARA Annual Report 1999, p.259 - 261, 2000/10

no abstracts in English

Journal Articles

Present status and activities of High energy nuclear data evaluation; For future radiation utilization facilities

Fukahori, Tokio; Mukaiyama, Takehiko; Oyama, Yukio; Chiba, Satoshi; Takada, Hiroshi; Maekawa, Hiroshi; Shibata, Tokushi*; Nakamura, Takashi*; *; *; et al.

Nihon Genshiryoku Gakkai-Shi, 40(1), p.3 - 28, 1998/00

 Times Cited Count:1 Percentile:11.76(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Electrochemical calorimetry of D$$_{2}$$O electrolysis using a palladium cathode; An Undivided, open cell system

*; *; *; *; *; *; *; Oyama, Yukio; Nakamura, Tomoo; Shibata, Tokushi*; et al.

Bulletin of the Chemical Society of Japan, 63(9), p.2659 - 2664, 1990/09

 Times Cited Count:1 Percentile:15.91(Chemistry, Multidisciplinary)

no abstracts in English

JAEA Reports

Experimental research for shielding of combined matters

Uwamino, Yoshitomo*; Okubo, Toru*; Shibata, Seiichi*; Shibata, Tokushi*

PNC TJ2602 87-003, 32 Pages, 1988/03

PNC-TJ2602-87-003.pdf:0.6MB

None

Oral presentation

An Estimation of the fast-neutron fluence for the Hiroshima atomic bomb

Shibata, Tokushi

no journal, , 

An estimation of the fast neutron fluence for the Hiroshima Atomic Bomb was carried out. The method is to estimate the fluence using the amount of the $$^{63}$$Ni contents in copper samples, neutron spectrum for the Hiroshima Atomic Bomb, and the excitation function of the $$^{63}$$Cu(n, p) $$^{63}$$Ni reaction. The extraction method of the trace amount of the $$^{63}$$Ni from copper samples was developed. The $$^{63}$$Ni was measured by a low-background liquid-scintillation counter. The excitation function of the $$^{63}$$Cu(n,p) $$^{63}$$Ni reaction was measured. The fluence was obtained from the measured $$^{63}$$Ni amount using the neutron spectrum and the excitation function of the reaction. The obtained results are consistent with the values given by the new dosimetry system D02.

Oral presentation

Radiation safety at J-PARC

Nakashima, Hiroshi; Shibata, Tokushi; Sawahata, Kei; Miyamoto, Yukihiro; Nakane, Yoshihiro; Masukawa, Fumihiro; Seki, Kazunari; Sato, Koichi; Oguri, Tomomi*; Hirayama, Hideo*; et al.

no journal, , 

Aiming at studies on the latest basic science and the advancing nuclear technology, the J-PARC (Japan Proton Accelerator Research Complex) project is in progress, and the high-energy proton accelerator complex of the world highest intensity is under construction. Because of its very high beam power and its energy as well as the large-scale accelerator complex, we have encountered some difficult radiation problems in the radiation safety design. This paper reviews the radiation safety policy and methods for the design to overcome the problems on the radiation safety and the status of the radiation safety estimation for licensing of J-PARC.

Oral presentation

Neutron production double differential cross section for 10 MeV proton incidence on Be

Iwamoto, Yosuke; Matsuda, Norihiro; Sakamoto, Yukio; Ochiai, Kentaro; Nakane, Yoshihiro; Nakashima, Hiroshi; Shibata, Tokushi

no journal, , 

no abstracts in English

32 (Records 1-20 displayed on this page)