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Journal Articles

Self-shielding effect of double heterogeneity for plutonium burner HTGR design

Fukaya, Yuji; Goto, Minoru; Ohashi, Hirofumi

Annals of Nuclear Energy, 138, p.107182_1 - 107182_9, 2020/04

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

The investigation on self-shielding effect of double heterogeneity for plutonium burner High Temperature Gas-cooled Reactor (HTGR) design has been performed. Plutonium burner HTGR designed in the previous study by using the advantage of double heterogeneity to control excess reactivity. In the present study, the mechanism of the self-shielding effect is elucidated by the analysis of burn-up calculation and reactivity decomposition based on exact perturbation theory. As a result, it is revealed that the characteristics of burn-up reactivity are determined by resonance cross section peak at 1 eV of $$^{240}$$Pu due to the surface term of background cross section, this is, the characteristics of neutron leakage from fuel lump and collision to a moderator. Moreover, significant spectrum shift is caused during the burn-up period, and it enhances reactivity worth of $$^{239}$$Pu and $$^{240}$$Pu in EOL.

Journal Articles

Activation in injection area of J-PARC 3-GeV rapid cycling synchrotron and its countermeasures

Yamamoto, Kazami; Yamakawa, Emi*; Takayanagi, Tomohiro; Miki, Nobuharu*; Kamiya, Junichiro; Saha, P. K.; Yoshimoto, Masahiro; Yanagibashi, Toru*; Horino, Koki*; Nakanoya, Takamitsu; et al.

ANS RPSD 2018; 20th Topical Meeting of the Radiation Protection and Shielding Division of ANS (CD-ROM), 9 Pages, 2018/08

The existing beam power of the J-PARC Rapid Cycling Synchrotron is up to 500 kW, and higher radiation doses are concentrated in the injection area. These activations are caused by the interaction between the foil and the beam. To reduce dose exposure to workers near the injection point, we study a new design of the injection scheme. Experience has shown that eddy currents are generated in the metal flange near the magnet owing to the pulsed magnetic field, and the temperature exceeds 100 degrees C. The shield installed in the new injection system needs to have a layer structure, in which an insulator is inserted between iron shields to reduce the eddy current. From the results of the shielding calculation, even if 1 mm of polyethylene was inserted between two 9-mm-thick SUS 316 plates, which serve as shielding material, the shielding performance was reduced only about 5%, and we confirmed that it would function well.

Journal Articles

Review of $$gamma$$-ray exposure buildup factors

Matsuda, Norihiro; Onishi, Seiki*; Sakamoto, Yukio*; Nobuhara, Fumiyoshi*

Heisei 29-Nendo Kani Shahei Kaiseki Kodo Rebyu Wakingu Gurupu Katsudo Hokokusho (Internet), p.20 - 28, 2018/08

no abstracts in English

Journal Articles

Shielding effect on secondary cosmic-ray neutron- and muon-induced soft errors

Abe, Shinichiro; Sato, Tatsuhiko

Proceedings of Radiation Effects on Components and Systems Conference 2016 (RADECS 2016) (Internet), 5 Pages, 2016/00

Secondary cosmic-ray neutron have been recognized as a major cause of soft error for microelectronics on ground. Recently, the effect of secondary cosmic-ray muon on soft error is concerned as semiconductor devices become sensitive to radiation. In this study, we investigate the shielding effect on secondary cosmic-ray neutron- and muon-induced SER. Transports of secondary cosmic-ray neutrons and muons in a building are simulated by PHITS with considering distributions of energy and zenith-angle of secondary cosmic-rays by PARMA 4.0 which is the analytical model for estimating cosmic-ray fluxes nearly anytime and anywhere in the world. The calculated neutron fluxes are in surprisingly good agreement with measured data. The soft errors in 25-nm bulk-design NMOSFET caused by neutrons and muons in the open air and on the first floor of the building are analyzed based on the MSV model using PHITS. It is found that the shielding effect of the building only contributes to decrease neutron-induced SER. As a result, muon-induced SER is about 20% of that caused by neutron on the first floor. Therefore it is necessary to consider the secondary cosmic-ray muon-induced SER when reliability of devices used in the building is evaluated.

Journal Articles

Activation, Radiation shielding materials

Sukegawa, Atsuhiko; Iida, Hiromasa*; Itoga, Toshio*; Okumura, Keisuke; Kai, Tetsuya; Konno, Chikara; Nakashima, Hiroshi; Nakamura, Takashi*; Ban, Shuichi*; Yashima, Hiroshi*; et al.

Hoshasen Shahei Handobukku; Kisohen, p.299 - 356, 2015/03

no abstracts in English

Journal Articles

Homogeneity tests on neutron shield concrete

Okuno, Koichi*; Iikura, Hiroshi

Nuclear Science and Techniques, 25(S1), p.S010604_1 - S010604_5, 2014/12

no abstracts in English

Journal Articles

Education method on Monte Carlo Analysis in atomic energy

Sakurai, Kiyoshi; Yamamoto, Toshihiro

Nippon Genshiryoku Gakkai Wabun Rombunshi, 4(4), p.248 - 258, 2005/12

no abstracts in English

Journal Articles

Experiment and analyses for 14 MeV neutron streaming through a dogleg duct

Yamauchi, Michinori*; Ochiai, Kentaro; Morimoto, Yuichi*; Wada, Masayuki*; Sato, Satoshi; Nishitani, Takeo

Radiation Protection Dosimetry, 116(1-4), p.542 - 546, 2005/12

 Times Cited Count:3 Percentile:73.72(Environmental Sciences)

no abstracts in English

Journal Articles

Shielding design of the ITER NBI Duct for nuclear and bremsstrahlung radiation

Sato, Satoshi; Iida, Hiromasa; Yamauchi, Michinori*; Nishitani, Takeo

Radiation Protection Dosimetry, 116(1-4), p.28 - 31, 2005/12

 Times Cited Count:2 Percentile:80.84(Environmental Sciences)

no abstracts in English

Journal Articles

Nuclear "pasta" structures and the charge screening effect

Maruyama, Toshiki; Tatsumi, Toshitaka*; Voskresensky, D. N.*; Tanigawa, Tomonori; Chiba, Satoshi

Physical Review C, 72(1), p.015802_1 - 015802_11, 2005/07

 Times Cited Count:138 Percentile:1.05(Physics, Nuclear)

no abstracts in English

JAEA Reports

Shielding design for target trolley for a spallation neutron source in the J-PARC project

Tamura, Masaya; Maekawa, Fujio; Harada, Masahide; Haga, Katsuhiro; Konno, Chikara

JAERI-Tech 2005-020, 58 Pages, 2005/03

JAERI-Tech-2005-020.pdf:18.82MB

no abstracts in English

Journal Articles

Structured mixed phase at charged kaon condensation

Maruyama, Toshiki; Tatsumi, Toshitaka*; Voskresensky, D. N.*; Tanigawa, Tomonori; Chiba, Satoshi

Nuclear Physics A, 749, p.186c - 189c, 2005/03

no abstracts in English

Journal Articles

Radiation safety design study of J-PARC (Japan Proton Accelerator Research Complex)

Nakashima, Hiroshi; Safety Group of J-PARC

Monte Karuro Keisanho Kodoka No Genjo; Dai-3-Kai Monte Karuro Shimyureshon Kenkyukai Hobunshu, p.75 - 83, 2004/12

Design policy for radiation safety issues, design criteria, calculation conditions for shielding design, method for design and safety estimation and the present status of shielding design are reported in Japan Proton Accelerator Research Complex.

Journal Articles

Neutron shielding and blanket neutronics design

Yamauchi, Michinori*; Nishitani, Takeo; Nishio, Satoshi

Purazuma, Kaku Yugo Gakkai-Shi, 80(11), p.952 - 954, 2004/11

Considering the geometrical characteristics of tokamak reactors with low aspect ratio, a basic neutronics strategy was derived to construct the inboard structure mainly for neutron shielding and produce enough tritium in the outboard blanket. The designs for optimal inboard shield were surveyed and necessary thickness was estimated to make the neutron flux low enough on the super-conducting magnet. In addition, the outer blanket designs were studied to attain the tritium breeding ratio (TBR) large enough for a self-sustaining fusion reactor on the basis of the advanced fusion reactor materials.

Journal Articles

Estimation of radioactivity and residual $$gamma$$-ray dose around a collimator at 3-GeV proton synchrotron ring of J-PARC facility

Nakane, Yoshihiro; Nakano, Hideo*; Abe, Teruo*; Nakashima, Hiroshi

Proceedings of 11th International Congress of the International Radiation Protection Association (IRPA-11) (CD-ROM), 6 Pages, 2004/05

no abstracts in English

Journal Articles

Benchmark experiments of dose distributions in phantom placed behind iron and concrete shields at the TIARA facility

Nakane, Yoshihiro; Sakamoto, Yukio; Tsuda, Shuichi; Tanaka, Susumu; Hirayama, Hideo*

Journal of Nuclear Science and Technology, 41(Suppl.4), p.506 - 509, 2004/03

no abstracts in English

Journal Articles

Progress in physics and technology developments for the modification of JT-60

Tamai, Hiroshi; Matsukawa, Makoto; Kurita, Genichi; Hayashi, Nobuhiko; Urata, Kazuhiro*; Miura, Yushi; Kizu, Kaname; Tsuchiya, Katsuhiko; Morioka, Atsuhiko; Kudo, Yusuke; et al.

Plasma Science and Technology, 6(1), p.2141 - 2150, 2004/02

 Times Cited Count:2 Percentile:92.88(Physics, Fluids & Plasmas)

The dominant issue for the the modification program of JT-60 (JT-60SC) is to demonstrate the steady state reactor relevant plasma operation. Physics design on plasma parameters, operation scenarios, and the plasma control method are investigated for the achievement of high-$$beta$$. Engineering design and the R&D on the superconducting magnet coils, radiation shield, and vacuum vessel are performed. Recent progress in such physics and technology developments is presented.

Journal Articles

Analytical representation for neutron streaming through slits in fusion reactor blanket by Monte Carlo calculation

Sato, Satoshi; Maki, Koichi*

Fusion Engineering and Design, 65(4), p.501 - 524, 2003/07

 Times Cited Count:2 Percentile:88.3(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

Tamura, Masaya; Maekawa, Fujio

JAERI-Tech 2003-010, 54 Pages, 2003/03

JAERI-Tech-2003-010.pdf:7.97MB

Evaluation of shielding performance for a spallation neutron source facility in the J-PARC Project is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. Horizontal required shield thicknesses were ranged from about 6.5m to 7.5m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results.

JAEA Reports

Japanese contribution to the design of primary module of shielding blanket in ITER-FEAT

Kuroda, Toshimasa*; Hatano, Toshihisa; Miki, Nobuharu*; Hiroki, Seiji; Enoeda, Mikio; Omori, Junji*; Sato, Shinichi*; Akiba, Masato

JAERI-Tech 2002-098, 136 Pages, 2003/02

JAERI-Tech-2002-098.pdf:24.33MB

no abstracts in English

252 (Records 1-20 displayed on this page)