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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.

JAEA Reports

Chemical state of tritium in Sr-Ce oxide ceramics and its removal characteristics (Cooperative research)

Nakamura, Hirofumi; Nishi, Masataka; Morita, Kenji*

JAERI-Research 2003-016, 32 Pages, 2003/08

JAERI-Research-2003-016.pdf:5.5MB

As a part of the detritiation study from the fusion reactor materials, chemical state of tritium injected into Sr-Ce base oxide ceramic proton conductor, which is a candidate for a tritium recovery system, was investigated with thermal desorption method. The results indicated that the oxide has to be heated up over 1300K to remove tritium due to the OT bond formation in the oxide. On the other hand, tritium removal behavior from the oxide were also investigated by exposing to humid air, and the mechanism of tritium removal from the oxide was identified by the dependency of tritium removal amount and chemical state on the humidity. The results revealed that tritium removal rate by the air exposure was low, and that almost tritium was removed as the vapor form, which was attributed to the isotope exchange reaction between the OT bond on the surface and the protium in vapor. It was also found that small amount of tritium was removed as elemental form under the humid air exposure, which could be attributed to the solute tritium in the oxide and oxygen absorption to the oxygen deficit in the oxide. As a result, the difference of the detritiation mechanism exposed to the humid air on the chemical state of tritium in the oxide was clarified, and it could be a useful basic data for the optimization of detritiation method.

Journal Articles