JOPSS - Search Results

Journal Articles

Fast dynamics of type I ELMs and transport of the ELM pulse in JT-60U

Oyama, Naoyuki; Asakura, Nobuyuki; Chankin, A. V.; Oikawa, Toshihiro; Sugihara, Masayoshi; Takenaga, Hidenobu; Itami, Kiyoshi; Miura, Yukitoshi; Kamada, Yutaka; Shinohara, Koji; et al.

Nuclear Fusion, 44(5), p.582 - 592, 2004/05

https://doi.org/10.1088/0029-5515/44/5/002

Times Cited Count：46 Percentile：80.18(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Fast ion loss calculation in the ripple compensation magnetic field by ferritic steel insertion using the FEMAG/OFMC code

Urata, Kazuhiro*; Shinohara, Koji; Suzuki, Masanobu*; Kamata, Isao*

JAERI-Data/Code 2004-007, 45 Pages, 2004/03

JAERI-Data-Code-2004-007.pdf:5.63MB

As the toroidal magnetic field generated by discrete TF coils involves magnetic field ripple, the fast ion loss is induced to damage vacuum vessel in tokamaks. An idea of ripple compensation using ferromagnetic is proposed. Since low activation ferritic steel have low activation and thermal conduction properties, the ferritic steel is planned to install in tokamak reactors. Installation of ferritic steel plates with toroidal symmetry is effective to compensate ripple, however in the actual devices it is difficult for interference with other components. Besides the first wall shapes are often asymmetric. So it is better to treat toroidal asymmetry to evaluate the ripple induced loss in the actual devices. For the purpose, magnetic field calculation code considering ferritic steel; FEMAG(FErrite generating MAGnetic field)has been speeded up. On the basis of this magnetic field data, OFMC (Orbit Following Monte Carlo) has been upgraded to treat toroidal asymmetry. The use of FEMAG/OFMC, applications to the JFT-2M experiments, and the national centralized tokamak facility are reported.

Journal Articles

Asymmetry of collapse of density pedestal by type I ELM on JT-60U

Oyama, Naoyuki; Miura, Yukitoshi; Chankin, A. V.; Takenaga, Hidenobu; Asakura, Nobuyuki; Kamada, Yutaka; Oikawa, Toshihiro; Shinohara, Koji; Takeji, Satoru

Nuclear Fusion, 43(10), p.1250 - 1257, 2003/10

https://doi.org/10.1088/0029-5515/43/10/028

Times Cited Count：16 Percentile：46.42(Physics, Fluids & Plasmas)

no abstracts in English

JAEA Reports

Extended calculations of OECD/NEA phase II-C burnup credit criticality benchmark problem for PWR spent fuel transport cask by using MCNP-4B2 code and JENDL-3.2 library

Kuroishi, Takeshi; Hoang, A.; Nomura, Yasushi; Okuno, Hiroshi

JAERI-Tech 2003-021, 60 Pages, 2003/03

JAERI-Tech-2003-021.pdf:4.56MB

The reactivity effect of the asymmetry of axial burnup profile is studied for PWR spent fuel transport cask proposed in OECD/NEA Phase II-C benchmark. The axial burnup profiles are based on in-core flux measurements. Criticality calculations are performed with the continuous energy Monte Carlo code MCNP-4B2 and the nuclear data library JENDL-3.2. Calculations are carried out not only for cases in the benchmark but also for symmetric burnup cases. Both actinide-only approach and actinide plus fission product approach is considered. The end effect is more sensitive to higher burnup asymmetry. The axial fission distribution becomes strongly asymmetric as its peak shifts toward the fuel top end. The peak of fission distribution gets higher with the increase of either the burnup asymmetry or the assembly-averaged burnup. The conservatism of uniform axial burnup assumption for the actinide-only approach is estimated quantitatively in comparison with the keff result calculated with experiment-based strongest asymmetric axial burnup profile for the actinide plus fission product approach.

Journal Articles

Asymmetry of dense divertor plasmas influenced by thermoelectric potential and charge-exchange momentum loss

Hayashi, Nobuhiko; Takizuka, Tomonori; Hosokawa, Masanari*; Shimizu, Katsuhiro

Journal of Nuclear Materials, 313-316(1-3), p.1041 - 1045, 2003/03

https://doi.org/10.1016/S0022-3115(02)01534-9

Times Cited Count：3 Percentile：25.75(Materials Science, Multidisciplinary)

Asymmetric equilibria of divertor plasmas influenced by the thermoelectric potential and the momentum loss due to the charge-exchange have been studied by using the five-point model. The momentum loss becomes large when the divertor plasma temperature decreases below about 10 eV. The pre-sheath potential is increased by the momentum loss and compensates for the decrease in the thermoelectric potential at the low-temperature side of the asymmetric equilibrium. Through The change of the pre-sheath potential, the momentum loss has a stabilizing effect on the thermoelectric instability and mitigates the asymmetry. To lower the temperature by the recycling at the one-side divertor, the high recycling and the resultant momentum loss at the other-side divertor are effective because of the bifurcated structure of the equilibrium.

Journal Articles

Nonlocal transport related to dynamics along magnetic field line

Takizuka, Tomonori; Hojo, Hitoshi*; Hatori, Tadatsugu*

Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.857 - 912, 2002/09

https://doi.org/10.1585/jspf.78.878

Transport along field lines in magnetic confinement plasmas is reviewed. Collisionless and collisional-diffusive transports are discussed. Because of their fast transport, features of plasmas along field lines are apt to behave nonlocally. A nonlocal phenomenon of scrape-off layer (SOL) and divertor plasmas in a tokamak is introduced, whose asymmetry along field lines is induced by the thermoelectric instability related to the SOL current. A local phenomenon called MARFE can be brought by the strong radiation cooling. The "snake" with nonlocal feature along field lines but with local structure perpendicular to the field is observed in a tokamak core plasma. For mirror-confined plasmas, axial particle losses from the mirror ends, especially pitch-angle-sattering losses into the loss cone and nondiabatic losses due to the breakdown of adiabaticity of the magnetic moment, are also discussed in the relation to nonlocal axial transport.

Journal Articles