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Journal Articles

Improving the safety of the high temperature gas-cooled reactor "HTTR" based on Japan's new regulatory requirements

Hamamoto, Shimpei; Shimizu, Atsushi; Inoi, Hiroyuki; Tochio, Daisuke; Homma, Fumitaka; Sawahata, Hiroaki; Sekita, Kenji; Watanabe, Shuji; Furusawa, Takayuki; Iigaki, Kazuhiko; et al.

Nuclear Engineering and Design, 388, p.111642_1 - 111642_11, 2022/03

Following the Fukushima Daiichi Nuclear Power Plant accident in 2011, the Japan Atomic Energy Agency adapted High-Temperature engineering Test Reactor (HTTR) to meet the new regulatory requirements that began in December 2013. The safety and seismic classifications of the existing structures, systems, and components were discussed to reflect insights regarding High Temperature Gas-cooled Reactors (HTGRs) that were acquired through various HTTR safety tests. Structures, systems, and components that are subject to protection have been defined, and countermeasures to manage internal and external hazards that affect safety functions have been strengthened. Additionally, measures are in place to control accidents that may cause large amounts of radioactive material to be released, as a beyond design based accident. The Nuclear Regulatory Commission rigorously and appropriately reviewed this approach for compliance with the new regulatory requirements. After nine amendments, the application to modify the HTTR's installation license that was submitted in November 2014 was approved in June 2020. This response shows that facilities can reasonably be designed to meet the enhanced regulatory requirements, if they reflect the characteristics of HTGRs. We believe that we have established a reference for future development of HTGR.

Journal Articles

Age-hardening mechanisms of heterogeneous-nanostructured SUS316LN stainless steel fabricated by heavy cold rolling

Miura, Hiromi*; Watanabe, Chihiro*; Aoyagi, Yoshiteru*; Oba, Yojiro; Kobayashi, Masakazu*; Yoshinaga, Naoki*

Materials Science & Engineering A, 833, p.142531_1 - 142531_12, 2022/01

Journal Articles

Spallation and fragmentation cross sections for 168 MeV/nucleon $$^{136}$$Xe ions on proton, deuteron, and carbon targets

Sun, X. H.*; Wang, H.*; Otsu, Hideaki*; Sakurai, Hiroyoshi*; Ahn, D. S.*; Aikawa, Masayuki*; Fukuda, Naoki*; Isobe, Tadaaki*; Kawakami, Shunsuke*; Koyama, Shumpei*; et al.

Physical Review C, 101(6), p.064623_1 - 064623_12, 2020/06

 Times Cited Count:2 Percentile:35.83(Physics, Nuclear)

The spallation and fragmentation reactions of $$^{136}$$Xe induced by proton, deuteron and carbon at 168 MeV/nucleon were studied at RIKEN Radioactive Isotope Beam Factory via the inverse kinematics technique. The cross sections of the lighter products are larger in the carbon-induced reactions due to the higher total kinetic energy of carbon. The energy dependence was investigated by comparing the newly obtained data with previous results obtained at higher reaction energies. The experimental data were compared with the results of SPACS, EPAX, PHITS and DEURACS calculations. These data serve as benchmarks for the model calculations.

Journal Articles

Energy of the $$^{229}$$Th nuclear clock isomer determined by absolute $$gamma$$-ray energy difference

Yamaguchi, Atsushi*; Muramatsu, Haruka*; Hayashi, Tasuku*; Yuasa, Naoki*; Nakamura, Keisuke; Takimoto, Misaki; Haba, Hiromitsu*; Konashi, Kenji*; Watanabe, Makoto*; Kikunaga, Hidetoshi*; et al.

Physical Review Letters, 123(22), p.222501_1 - 222501_6, 2019/11

 Times Cited Count:15 Percentile:86.53(Physics, Multidisciplinary)

Journal Articles

Enhancement of element production by incomplete fusion reaction with weakly bound deuteron

Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.

Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07

 Times Cited Count:5 Percentile:62.37(Physics, Multidisciplinary)

Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for $$^{107}$$Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.

Journal Articles

Present status of personnel protection system at J-PARC

Kikuzawa, Nobuhiro; Niki, Kazuaki*; Yamamoto, Noboru*; Hayashi, Naoki; Adachi, Masatoshi*; Watanabe, Kazuhiko*

Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.877 - 880, 2019/07

Interlock system of J-PARC is classified into a personnel protection system (PPS) for human safety and a machine protection system (MPS) for protecting equipment. The PPS of the J-PARC accelerator started from the operation at Linac in 2006 and was completed by the MR operation in 2008. In the next 10 years, some improvements have been made, such as updating video monitoring systems and establishing new interlocks. In addition to describing recent operations including these updatings, this paper reports the current status of inspections and maintenance conducted to maintain and improve reliability.

Journal Articles

Simulation, measurement, and mitigation of beam instability caused by the kicker impedance in the 3-GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex

Saha, P. K.; Shobuda, Yoshihiro; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Tamura, Fumihiko; Tani, Norio; Yamamoto, Masanobu; Watanabe, Yasuhiro; et al.

Physical Review Accelerators and Beams (Internet), 21(2), p.024203_1 - 024203_20, 2018/02

 Times Cited Count:6 Percentile:62.89(Physics, Nuclear)

Journal Articles

Achievement of a low-loss 1-MW beam operation in the 3-GeV rapid cycling synchrotron of the Japan Proton Accelerator Research Complex

Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kato, Shinichi; Kinsho, Michikazu; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Tani, Norio; et al.

Physical Review Accelerators and Beams (Internet), 20(6), p.060402_1 - 060402_25, 2017/06

 Times Cited Count:17 Percentile:87.54(Physics, Nuclear)

The 3-GeV rapid cycling synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) is the world's highest class of high-power pulsed proton driver, aiming for an output beam power of 1 MW. The most important issues in realizing such a high-power beam operation are to control and minimize beam loss for maintaining machine activations within permissible levels. In RCS, numerical simulation was successfully utilized along with experimental approaches to isolate the mechanism of beam loss and find its solution. By iteratively performing actual beam experiments and numerical simulations, and also by several hardware improvements, we have recently established a 1-MW beam operation with very low fractional beam loss of a couple of 10$$^{-3}$$. In this paper, our recent efforts toward realizing such a low-loss high-intensity beam acceleration are presented.

Journal Articles

Overview of JENDL-4.0/HE and benchmark calculations

Kunieda, Satoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Minato, Futoshi; Okamoto, Tsutomu; Sato, Tatsuhiko; Nakashima, Hiroshi; Iwamoto, Yosuke; Iwamoto, Hiroki; Kitatani, Fumito; et al.

JAEA-Conf 2016-004, p.41 - 46, 2016/09

Neutron- and proton-induced cross-section data are required in a wide energy range beyond 20 MeV, for the design of accelerator applications. New evaluations are performed with recent knowledge in the optical and pre-equilibrium model calculations. We also evaluated cross-sections for p+$$^{6,7}$$Li and p+$$^{9}$$Be which have been highly requested from a medical field. The present high-energy nuclear data library, JENDL-4.0/HE, includes evaluated cross-sections for incident neutrons and protons up to 200 MeV (for about 130 nuclei). We overview substantial features of the library, i.e., (1) systematic evaluation with CCONE code, (2) challenges for evaluations of light nuclei and (3) inheritance of JENDL-4.0 and JENDL/HE-2007. In this talk, we also focus on the results of benchmark calculation for neutronics to show performance of the present library.

Journal Articles

Simulation studies and measurements of beam instabilities caused by the kicker impedance at high intensities in the 3-GeV RCS of J-PARC

Saha, P. K.; Shobuda, Yoshihiro; Hotchi, Hideaki; Harada, Hiroyuki; Hayashi, Naoki; Kinsho, Michikazu; Nomura, Masahiro; Tamura, Fumihiko; Tani, Norio; Watanabe, Yasuhiro; et al.

Proceedings of 7th International Particle Accelerator Conference (IPAC '16) (Internet), p.589 - 591, 2016/06

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2015-030, 115 Pages, 2015/12

JAEA-Review-2015-030.pdf:25.28MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

Journal Articles

Yrast 6$$^+$$ seniority isomers of $$^{136,138}$$Sn

Simpson, G. S.*; Gey, G.*; Jungclaus, A.*; Taprogge, J.*; Nishimura, Shunji*; Sieja, K.*; Doornenbal, P.*; Lorusso, G.*; S$"o$derstr$"o$m, P.-A.*; Sumikama, Toshiyuki*; et al.

Physical Review Letters, 113(13), p.132502_1 - 132502_6, 2014/09

 Times Cited Count:56 Percentile:92.53(Physics, Multidisciplinary)

Journal Articles

Monopole-driven shell evolution below the doubly magic nucleus $$^{132}$$Sn explored with the long-lived isomer in $$^{126}$$Pd

Watanabe, H.*; Lorusso, G.*; Nishimura, Shunji*; Otsuka, T.*; Ogawa, K.*; Xu, Z. Y.*; Sumikama, Toshiyuki*; S$"o$derstr$"o$m, P.-A.*; Doornenbal, P.*; Li, Z.*; et al.

Physical Review Letters, 113(4), p.042502_1 - 042502_6, 2014/07

 Times Cited Count:21 Percentile:78.3(Physics, Multidisciplinary)

Journal Articles

Progress of injection energy upgrade project for J-PARC RCS

Hayashi, Naoki; Harada, Hiroyuki; Horino, Koki; Hotchi, Hideaki; Kamiya, Junichiro; Kinsho, Michikazu; Saha, P. K.; Shobuda, Yoshihiro; Takayanagi, Tomohiro; Tani, Norio; et al.

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.3833 - 3835, 2014/07

no abstracts in English

Journal Articles

Power supply of the pulse steering magnet for changing the painting area between the MLF and the MR at J-PARC 3 GeV RCS

Takayanagi, Tomohiro; Hayashi, Naoki; Ueno, Tomoaki; Horino, Koki; Togashi, Tomohito; Kinsho, Michikazu; Watanabe, Yasuhiro; Irie, Yoshiro*

Proceedings of 4th International Particle Accelerator Conference (IPAC '13) (Internet), p.681 - 683, 2014/07

The power supply of the pulse steering magnet has been produced. The power supply has the equipment used to excite the pulse current and the direct-current (DC) to correspond to two modes that the painting injection for beam users and the central injection for beam commissioning. The pulse current has been performed with good accuracy whose deviation to a setting current becomes to be less than 0.2%. In case of the central injection, the power supply excites the current in DC mode, which has been realized the ripple current below 0.01%. This paper describes the design parameters and the experimental results of the power supply.

Journal Articles

Design consideration of beam duct for quadrupole correctors in J-PARC RCS

Kamiya, Junichiro; Kinsho, Michikazu; Hayashi, Naoki; Hotchi, Hideaki; Ogiwara, Norio; Tani, Norio; Watanabe, Yasuhiro

Journal of the Vacuum Society of Japan, 57(4), p.131 - 135, 2014/04

In J-PARC 3GeV synchrotron (RCS), new quadrupole magnets (quadrupole correctors) are planned to be installed in order to correct the edge focusing effect and tune. In this report, we describe a deliberation flow about the design of the beam ducts, which are installed in the quadrupole corrector. The effects of eddy current were examined in the case of the titanium duct. The calculated results showed that the temperature rise was too much (up to over 350$$^{circ}$$C) and the magnetic field in the beam duct is largely distorted. Therefore we decided to employ alumina ceramics beam ducts. The stress and displacement, which are caused by the atmospheric pressure, were estimated by simulating the realistic equipments in the beam line. It was found that there was no large stress and displacement by installing the alumina ceramics duct.

Journal Articles

$$1p_{3/2}$$ proton-hole state in $$^{132}$$Sn and the shell structure along $$N$$=82

Taprogge, J.*; Jungclaus, A.*; Grawe, H.*; Nishimura, Shunji*; Doornenbal, P.*; Lorusso, G.*; Simpson, G.*; S$"o$derstr$"o$m, P.-A.*; Sumikama, Toshiyuki*; Xu, Z. Y.*; et al.

Physical Review Letters, 112(13), p.132501_1 - 132501_6, 2014/04

 Times Cited Count:45 Percentile:90.05(Physics, Multidisciplinary)

Journal Articles

Three-dimensional and multienergy $$gamma$$-ray simultaneous imaging by using a Si/CdTe Compton camera

Suzuki, Yoshiyuki*; Yamaguchi, Mitsutaka; Odaka, Hirokazu*; Shimada, Hirofumi*; Yoshida, Yukari*; Torikai, Kota*; Sato, Takahiro; Arakawa, Kazuo*; Kawachi, Naoki; Watanabe, Shigeki; et al.

Radiology, 267(3), p.941 - 947, 2013/06

 Times Cited Count:10 Percentile:42.69(Radiology, Nuclear Medicine & Medical Imaging)

Journal Articles

Corrosion modeling for carbon steel under oxygen depleted underground environment

Shibata, Toshio*; Watanabe, Masatoshi; Taniguchi, Naoki; Shimizu, Akihiko*

Zairyo To Kankyo, 62(2), p.70 - 77, 2013/02

In the oxygen depleted underground environment, carbon steel reacts with H$$_{2}$$O, producing H$$_{2}$$ gas and forming corrosion film on the steel surface. Corrosion rate is controlled by diffusion of reaction species through corrosion film. Diffusion constants of some species working in the corrosion process were obtained from literatures. However, no data were found on the diffusion constant of H$$_{2}$$O in iron oxides based on an appropriate assumption. Mass transfer model for the corrosion rate was used to simulate the corrosion rate of carbon steel. Liquid phase diffusion model of Fe$$^{2+}$$ or H$$_{2}$$O through pores in the corrosion film and solid phase diffusion model of H$$_{2}$$O through corrosion film itself were examined by Excel simulation. Change in corrosion current density and corrosion loss with time and pH and temperature dependence of corrosion current density were examined. By comparing the results, it is suggested that the solid phase diffusion of H$$_{2}$$O in the corrosion film controls the corrosion rate of carbon steel in oxygen depleted environment.

Journal Articles

An Evaluation of three-dimensional imaging by use of Si/CdTe Compton cameras

Yamaguchi, Mitsutaka; Nagao, Yuto; Kawachi, Naoki; Fujimaki, Shu; Kamiya, Tomihiro; Odaka, Hirokazu*; Kokubun, Motohide*; Takeda, Shinichiro*; Watanabe, Shin*; Takahashi, Tadayuki*; et al.

Proceedings of 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC), 3 Pages, 2013/00

135 (Records 1-20 displayed on this page)