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Journal Articles

Effect of B$$_{4}$$C absorber material on melt progression and chemical forms of iodine or cesium under severe accident conditions

Hidaka, Akihide

Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.341 - 356, 2021/10

Journal Articles

Current status of the high intensity pulsed spallation neutron source at J-PARC

Takada, Hiroshi

Plasma and Fusion Research (Internet), 13(Sp.1), p.2505013_1 - 2505013_8, 2018/03

The pulsed spallation neutron source of Japan Proton Accelerator Research Complex (J-PARC) has been supplying users with high intensity and sharp pulse cold neutrons using the moderators with following distinctive features; (1) 100% para-hydrogen for increasing pulse peak intensity with decreasing pulse tail, (2) cylindrical shape with 14 cm diam.$$times$$12 cm long for providing high intensity neutrons to wide neutron extraction angles of 50.8$$^{circ}$$, (3) neutron absorber made from Ag-In-Cd alloy to make pulse width narrower and pulse tails lower. Actually, it was measured at a low power operation that high neutron intensity of 4.5$$times$$10$$^{12}$$ n/cm$$^{2}$$/s/sr could be emitted from the coupled moderator surface for 1-MW operation, and a superior resolution of $$Delta$$d/d = 0.035% was achieved at a beamline (BL8) with a poisoned moderator, where d is the d-spacing of reflection. Towards the goal to achieve the target operation at 1-MW for 5000 h in a year, technical developments to mitigate cavitation damages on the target vessel with injecting gas micro-bubbles into mercury target and design improvement of target vessel structure to reducing welds and bolt connections as much as possible are under way.

Journal Articles

Implementation of a low-activation Au-In-Cd decoupler into the J-PARC 1 MW short pulsed spallation neutron source

Teshigawara, Makoto; Ikeda, Yujiro; Oi, Motoki; Harada, Masahide; Takada, Hiroshi; Kakishiro, Masanori*; Noguchi, Gaku*; Shimada, Tsubasa*; Seita, Kyoichi*; Murashima, Daisuke*; et al.

Nuclear Materials and Energy (Internet), 14, p.14 - 21, 2018/01

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

We developed an Au-In-Cd (AuIC) decoupler material to reduce induced radioactivity instead of Ag-In-Cd one, which has a cut off energy of 1eV. In order to implement it into an actual moderator-reflector assembly, a number of critical engineering issues need to be resolved with regard to large-sized bonding between AuIC and A5083 alloys by the hot isostatic pressing process. We investigated this process in terms of the surface conditions, sizes, and heat capacities of large AuIC alloys. We also show a successful implementation of an AuIC decoupler into a reflector assembly, resulting in a remarkable reduction of radioactivity by AuIC compared to AIC without sacrificing neutronic performance.

Journal Articles

Release behavior of Cs and its chemical form during late phase of Fukushima Daiichi Nuclear Power Plant accident

Hidaka, Akihide; Yokoyama, Hiroya

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2017 (AWC 2017) (USB Flash Drive), p.29 - 42, 2017/09

no abstracts in English

Journal Articles

Effect of B$$_{4}$$C absorber material on melt progression and chemical forms of iodine or cesium under severe accident conditions

Hidaka, Akihide

Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(1), p.51 - 61, 2015/03

B$$_{4}$$C used mainly for BWR and EPR absorbers could cause phenomena which never happen in PWR with Ag-In-Cd absorbers during severe accident. B$$_{4}$$C would make a eutectic interaction with stainless steel and enhance melt relocation. Boron oxidation could increase H$$_{2}$$ generation and change of liberated carbon to CH$$_{4}$$ could enhance CH$$_{3}$$I generation. HBO$$_{2}$$ generated during B$$_{4}$$C oxidation could be changed to CsBO$$_{2}$$ by combining with Cs. This may increase Cs deposition in reactor coolant system. There could be differences in configuration, surface area, stainless steel-B$$_{4}$$C weight ratio between B$$_{4}$$C powder and pellet absorbers. Present issue is to clarify effect of these differences on full scale melt progression, B$$_{4}$$C oxidation and source term. Advancement of this research domain could contribute to further sophistication of prediction tool for melt progression and source terms, and treatment of organic iodide formation in safety evaluation.

Journal Articles

Extension of effective cross section calculation method for neutron transport calculations in particle-dispersed media

Yamamoto, Toshihiro; Miyoshi, Yoshinori; Takeda, Toshikazu*

Journal of Nuclear Science and Technology, 43(1), p.77 - 87, 2006/01

 Times Cited Count:6 Percentile:43.58(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of control technology for the HTTR hydrogen production system

Nishihara, Tetsuo; Inagaki, Yoshiyuki

Nuclear Technology, 153(1), p.100 - 106, 2006/01

 Times Cited Count:8 Percentile:52.29(Nuclear Science & Technology)

Japan Atomic Energy Research Institute (JAERI) has performed the research and development of hydrogen production using the high temperature engineering test reactor (HTTR). One of the key issues for the HTTR hydrogen production system is the development of control technology for stable operation. A thermal load absorber concept using a steam generator installed downstream of a reformer is proposed to mitigate a variation of helium temperature. Thermal hydraulic analyses for the start up operation and the suspension of feed gas supply to the reformer are carried out. These results show that a large variation of the reformer outlet helium temperature takes place due to a change of the feed gas flow rate. However the steam generator can mitigate the variation of helium temperature. It is clarified that the HTTR can continue normal operation independently of the feed gas flow rate.

Journal Articles

Development of control technology for the HTGR hydrogen production system

Nishihara, Tetsuo; Inagaki, Yoshiyuki

Proceedings of GLOBAL2003 Atoms for Prosperity; Updating Eisenhower's Global Vision for Nuclear Energy (CD-ROM), p.320 - 324, 2003/00

HTGR hydrogen production system has potential possibility to provide hydrogen without CO$$_{2}$$ emission. Key technology for developing this system is to establish the control technology for preventing propagation of thermal turbulence from the hydrogen production system to the HTGR. Japan Atomic Energy Research Institute (JAERI) has planed a demonstration test of hydrogen production using an HTGR named high temperature engineering test reactor (HTTR) to develop the control technology. Thermal load absorber concept using the steam generator located downstream of the chemical reactor is proposed to mitigate the variation of outlet helium temperature of the chemical reactor. This concept leads to the stable controllability and enables to operate the HTGR and the hydrogen production plant independently. Plant simulation analyses are carried out to verify the performance of this concept.

Journal Articles

RAPID-L highly automated fast reactor concept without any control rods, 2; Critical experiment of lithium-6 used in LEM and LIM

Tsunoda, Hirokazu*; Sato, Osamu*; Okajima, Shigeaki; Yamane, Tsuyoshi; Iijima, Susumu; Kobe, Mitsuru*

Proceedings of International Congress on Advanced Nuclear Power Plants (ICAPP) (CD-ROM), 6 Pages, 2002/00

no abstracts in English

JAEA Reports

Study of burnable absorber reactivity worth evaluation method considering the position of burnable absorber rod in a block using VHTRC experimental results

Fujimoto, Nozomu; Yamashita, Kiyonobu; Akino, Fujiyoshi

JAERI-Research 99-052, p.51 - 0, 1999/09

JAERI-Research-99-052.pdf:2.05MB

no abstracts in English

JAEA Reports

Neutronics design of JMTR-LEU core

Nagaoka, Yoshiharu; Komukai, Bunsaku; ; Koike, Sumio; Saito, Minoru;

JAERI-M 92-098, 81 Pages, 1992/07

JAERI-M-92-098.pdf:1.81MB

no abstracts in English

Journal Articles

Oxidation behavior of boronated graphite in helium containing water vapor

Fujii, Kimio; Nomura, Shinzo; *; Shindo, Masami

Journal of Nuclear Materials, 187, p.32 - 38, 1992/00

 Times Cited Count:7 Percentile:58.5(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Progress in safety evaluation for the JMTR core conversion to LEU fuel

; ; Saito, Junichi; Komukai, Bunsaku; Ando, Hiroei; ; ; ; Saito, Minoru;

Proc. on 12th Int. Meeting,Reduced Enrichment for Research and Test Reactors, p.269 - 280, 1991/00

no abstracts in English

Journal Articles

Experimental study on reactivity worth for absorber material in high conversion light water reactor using FCA-HCLWR core fueled with enriched uranium

Okajima, Shigeaki; Osugi, Toshitaka; Sakurai, Takeshi; *

Journal of Nuclear Science and Technology, 27(10), p.950 - 959, 1990/10

no abstracts in English

Journal Articles

Response matrix of symmetric nodes with absorber rods

Annals of Nuclear Energy, 14(8), p.451 - 454, 1987/08

 Times Cited Count:3 Percentile:52.81(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Investigation of space-dependent neutron flux fluctuation excited by absorber

;

Annals of Nuclear Energy, 10(11), p.589 - 599, 1983/00

 Times Cited Count:1 Percentile:22.86(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Critical Experiment on the Decrease of Power Gradient by Using 「Gray Nose Control Rod」

; ; ; Ono, Akio; Murakami, Kiyonobu; *; *; *; *

JAERI-M 8020, 162 Pages, 1979/01

JAERI-M-8020.pdf:4.57MB

no abstracts in English

Oral presentation

Design and fabrication of novel broadband near-perfect black absorber having microstructured surface

Amemiya, Kuniaki*; Koshikawa, Hiroshi; Yamaki, Tetsuya; Maekawa, Yasunari; Shitomi, Hiroshi*; Kinoshita, Kenichi*; Numata, Takayuki*; Tanabe, Minoru*; Fukuda, Daiji*

no journal, , 

The novel broadband near-perfect black absorber for an absolute radiometer has been developed. Microstructured surface having high-aspect-ratio conical pores was fabricated by swift heavy ion beam irradiation and following etching process; subsequently, the surface was coated with black layer. Incident light which enters into the surface microstructure experiences multiple reflections which enhance optical absorption; therefore, the net reflectance decreases much less than 1% with sufficient pit aspect ratio and absorption layer thickness, which can be designed by finite differential time domain (FDTD) method calculation. Furthermore, a prototype of the novel black absorber also exhibited good mechanical durability. This newly developed black material is also expected to have potential application in various fields of optical energy management such as stray light elimination.

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