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Journal Articles

Development of experimental technology for simulated fuel-assembly heating to address core-material-relocation behavior during severe accident

Abe, Yuta; Yamashita, Takuya; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro

Journal of Nuclear Engineering and Radiation Science, 6(2), p.021113_1 - 021113_9, 2020/04

Journal Articles

Development of experimental technology for simulated fuel-assembly heating to address core-material-relocation behavior during severe accident

Abe, Yuta; Yamashita, Takuya; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 9 Pages, 2018/07

Journal Articles

Evaluation and demonstration of cutting the fuel assembly heating examination by AWJ

Maruyama, Shinichiro*; Watatani, Satoshi*

Mitsui Sumitomo Kensetsu Gijutsu Kenkyu Kaihatsu Hokoku, (15), p.107 - 112, 2017/10

It is essential to estimate characteristics and forms of fuel debris for safe and reliable removing at the decommissioning of the Fukushima Daiichi Nuclear Power Plant (1F). For the estimation, melting behavior of fuel assembly in the accident is being researched. To proceed the research, the fuel debris were need to cut, and the abrasive water jet (AWJ) which had enough results for cutting ceramic material or mixed material of zirconium alloy and stainless. The test results demonstrated that AWJ could cut the fuel assembly and accumulated the cutting data which will be subservient when removing the fuel debris in future.

Journal Articles

Development of non-transfer type plasma heating technology to address CMR behavior during severe accident with BWR design conditions

Abe, Yuta; Sato, Ikken; Nakagiri, Toshio; Ishimi, Akihiro; Nagae, Yuji

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

Journal Articles

Preparation for a new experimental program addressing core-material-relocation behavior during severe accident with BWR design conditions; Conduction of preparatory tests applying non-transfer-type plasma heating technology

Abe, Yuta; Sato, Ikken; Ishimi, Akihiro; Nakagiri, Toshio; Nagae, Yuji

Proceedings of 24th International Conference on Nuclear Engineering (ICONE-24) (DVD-ROM), 7 Pages, 2016/06

A new experimental program using non-transfer type plasma heating is under consideration in JAEA to clarify the uncertainty on core-material relocation (CMR) behavior of BWR. In order to confirm the applicability of this new technology, authors performed preparatory plasma heating tests using small-scale test pieces (107 mm $$times$$ 107 mm $$times$$ 222 mmh). Based on these preliminary results, an excellent perspective in terms of applicability of the non-transfer plasma heating technology to the SA (Severe Accident) experimental study was obtained. Furthermore, JAEA is preparing for the next step intermediate-scale preparatory tests in 2016 using ca. 50 rods and a control blade that would not only confirm its technical applicability, but also some insights relevant to the issue on CMR itself.

Journal Articles

Computational and experimental examination of simulated core damage and relocation dynamics of a BWR fuel assembly

Hanus, G.*; Sato, Ikken; Iwama, Tatsuya*

Proceedings of International Waste Management Symposia 2016 (WM2016) (Internet), 12 Pages, 2016/03

JAEA plans a large-scale test to evaluate damage and relocation behavior of BWR core materials consisting of fuel rods, channel boxes, control blade and lower support structures. Its purpose is to contribute to understanding of core material relocation behavior in the event of severe accidents with the BWR design conditions for which existing experimental database is quite limited. Prior to large-scale testing, JAEA desires preliminary investigations to examine melting test pieces. The purpose of such tests is to verify the materials and test piece will be heated by plasma to the target temperature (ca.2900K) and to collect data about the material relocation behavior. Results from preliminary computational simulations are presented illustrating the effectiveness of a 150 kW non-transferred plasma jet. An experimental test program using the computational analyses as a basis and a plasma torch is described.

Journal Articles

Rapid dissolution techniques with microwave heating devices for solidified products made from non-metallic wastes by plasma melting

Haraga, Tomoko; Kameo, Yutaka; Nakashima, Mikio

Bunseki Kagaku, 55(1), p.51 - 54, 2006/01

 Times Cited Count:4 Percentile:14.97(Chemistry, Analytical)

A relatively large quantity of sample solutions have to be prepared for radiochemical analysis of solidified products yielded by plasma melting treatment of non-metallic radioactive wastes. In order to dissolve the solidified products sample rapidly, dissolution method with microwave heating devices was applied. In a conventional method only by external heating with various mixtures of acids (HNO$$_{3}$$, HF, HClO$$_{4}$$ and H$$_{2}$$SO$$_{4}$$), a 0.1 g amount of the sample was dissolved with difficulty. However, applying the microwave assisted dissolution method, a 1 g amount of the sample was completely dissolved in a shorter time. Thereby the time for dissolution procedures was shortened less than a one-tenth. The present dissolution method was successfully applied to the blast furnace slag as a reference material to determine main elements with good precision.

Journal Articles

Plasma profile control by using local heating and current drive with EC waves

Ikeda, Yoshitaka; Kubo, Shin*

Purazuma, Kaku Yugo Gakkai-Shi, 81(3), p.160 - 166, 2005/03

The local profile controls of electron temperature and current in fusion-oriented devices using the electron cyclotron (EC) wave is reviewed. Recent progress of the EC heating system that enabled those controls is briefly described. The specific feature of EC wave heating is local and high power density heating properties. Current drive and electron temperature profile control experiments using EC wave performed in order to improve and investigate plasma confinement properties are discussed.

Journal Articles

Intelligible seminor on fusion reactors, 3; Plasma heating system to generate high temperature fusion palsmas

Inoue, Takashi; Sakamoto, Keishi

Nihon Genshiryoku Gakkai-Shi, 47(2), p.120 - 127, 2005/02

no abstracts in English

Journal Articles

Generation of X-rays and energetic ions from superintense laser irradiation of micron-sized Ar clusters

Fukuda, Yuji; Akahane, Yutaka; Aoyama, Makoto; Inoue, Norihiro*; Ueda, Hideki; Kishimoto, Yasuaki; Yamakawa, Koichi; Faenov, A. Y.*; Magunov, A. I.*; Pikuz, T. A.*; et al.

Laser and Particle Beams, 22(3), p.215 - 220, 2004/07

 Times Cited Count:41 Percentile:79.45(Physics, Applied)

High resolution K-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 10$$^{19}$$ W/cm$$^2$$ and a pulse duration of 30 fs. The total photon flux of 2$$times$$10$$^8$$ photons/pulse was achieved for He$$_{alpha1}$$ resonant line of Ar ($$lambda$$=3.9491 AA , 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply-charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance towards the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.

Journal Articles

Formation of a charge-exchange target for fast ions in the plasma of large-scale toroidal devices under NBI conditions

Mironov, M. I.*; Khudoleev, A. V.*; Kusama, Yoshinori

Plasma Physics Reports, 30(2), p.164 - 168, 2004/02

 Times Cited Count:0 Percentile:0.02(Physics, Fluids & Plasmas)

High-energy charge-exchange diagnostics can determine the distribution function of fast atoms produced via the neutralization of hydrogen ions by hydrogen-like impurity ions. Deriving the distribution function requires to know the composition and spatial distribution of the target ions in a plasma. A charge-exchange target forms as a result of the interaction between impurity nuclei and beam atoms. Depending on the arrangement of heating beams with respect to the diagnostics, it is necessary to calculate their trajectories. A model which takes into account elementary processes resulting in the ionization equilibrium of the ions of impurities in a specific tokamak configuration is proposed. The model is applied to the JT-60U plasma. Mechanisms for the formation of charge-exchange atomic flows are considered. The relative contributions of different heating injectors to the charge-exchange flow are estimated. Based on the calculated results, a method is proposed for local measurements of the ion distribution function with a stationary analyzer.

Journal Articles

Accelerator R&D for JT-60U and ITER NB systems

Inoue, Takashi; Hanada, Masaya; Iga, Takashi*; Imai, Tsuyoshi; Kashiwagi, Mieko; Kawai, Mikito; Morishita, Takatoshi; Taniguchi, Masaki; Umeda, Naotaka; Watanabe, Kazuhiro; et al.

Fusion Engineering and Design, 66-68, p.597 - 602, 2003/09

 Times Cited Count:21 Percentile:79.16(Nuclear Science & Technology)

The neutral beam (NB) injection has been one of the most promising methods for plasma heating and current drive in tokamak fusion devices. JAERI has developed high energy electrostatic accelerators for the NB systems in JT-60U and ITER. Recent progress on this R&D are as follows: 1) In the JT-60U NB system, some of the beams has been deflected due to distorted electric field in the accelerator, resulting in an excess heat load on the NB port. By correcting the electric field, a continuous injection of H$$^{0}$$ beam was succeeded for 10 s with the NB power of 2.6 MW at 355 keV. 2) To increase the beam energy, a metal structure called stress ring was designed. The ring reduces electric field concentration at the triple junction point (interface between metal and dielectric insulator inside vacuum). Initial test of the accelerators with the stress rings has shown higher voltage hold off performance in both accelerators for JT-60U and ITER R&D than that without rings.

Journal Articles

Neutral beam injectors for ITER and tokamak fusion reactors

Inoue, Takashi

Purazuma, Kaku Yugo Gakkai-Shi, 78(5), p.398 - 404, 2002/05

Neutral beam (NB) heating and current drivesystem for ITER fires the energetic particle beams of 1 MeV, 33 MW (16.5 MW/NB injector) into the fusion plasma. The design allows late installation of third NB injector for upgrade in current drive experiment toward steady state operation. The ITER NB system has been designed to fulfill requirements of the plasma physics, including advanced scenario achieved with off-axis current drive by NB. A design overview of the ITER NB system is described. The paper also reports recent R&D status of ion source and accelerator, as key components of the NB system, toward ITER construction. NB heating and current drive performance required in future tokamak reactors are discussed together with the necessary R&D issues.

Journal Articles

Design of neutral beam system for ITER-FEAT

Inoue, Takashi; Di Pietro, E.*; Hanada, Masaya; Hemsworth, R. S.*; Krylov, A.*; Kulygin, V.*; Massmann, P.*; Mondino, P. L.*; Okumura, Yoshikazu; Panasenkov, A.*; et al.

Fusion Engineering and Design, 56-57, p.517 - 521, 2001/10

 Times Cited Count:62 Percentile:96.47(Nuclear Science & Technology)

no abstracts in English

Journal Articles

ITER R&D: Auxiliary systems; Neutral beam heating and current drive system

Inoue, Takashi; Hemsworth, R. S.*; Kulygin, V.*; Okumura, Yoshikazu

Fusion Engineering and Design, 55(2-3), p.291 - 301, 2001/07

 Times Cited Count:24 Percentile:82.75(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Neutral beams for the International Thermonuclear Experimental Reactor

Inoue, Takashi; Di Pietro, E.*; Mondino, P. L.*; Bayetti, P.*; Hemsworth, R. S.*; Massmann, P.*; Fujiwara, Yukio; Hanada, Masaya; Miyamoto, Kenji; Okumura, Yoshikazu; et al.

Review of Scientific Instruments, 71(2), p.744 - 746, 2000/02

 Times Cited Count:17 Percentile:68.23(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Production of sheared flow during ion cyclotron resonance heating in tokamak plasmas

C.G.Liu*; Yamagiwa, Mitsuru; S.J.Qian*

Physics of Plasmas, 4(8), p.2788 - 2790, 1997/08

 Times Cited Count:3 Percentile:13.08(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Production of sheared flow by means of ICRF heating in tokamak plasmas

C.Liu*; Yamagiwa, Mitsuru; S.Qian*

JAERI-Research 96-068, 17 Pages, 1997/01


no abstracts in English

Journal Articles

Development of B$$_{4}$$C-carbon fiber composite ceramics as plasma facing materials in nuclear fusion reactor, 3; Heat resistance evaluation by electron beam irradiation and by in situ plasma discharge in JT-60

Jimbo, Ryutaro*; Saido, Masahiro; Nakamura, Kazuyuki; Akiba, Masato; ; Dairaku, Masayuki; *; *; *; *

Journal of the Ceramic Society of Japan, International Edition, 105, p.1179 - 1187, 1997/00

no abstracts in English

Journal Articles

Design and R&D of high power negative ion source/accelerator for ITER NBI

Inoue, Takashi; Okumura, Yoshikazu; Fujiwara, Yukio; Miyamoto, Kenji; Ohara, Yoshihiro; Miyamoto, Naoki*; Watanabe, Kazuhiro; B.Heinemann*; *

Fusion Technology 1996, 1, p.701 - 704, 1996/00

no abstracts in English

47 (Records 1-20 displayed on this page)