摘要:

Radiation damage of plasma facing materials and the behavior of impurities in the scrape-off layer, under steady-state discharge of superconducting tokamak TRIAM-1M, was examined with using a rotatable collector probe. TEM observations of metallic probe specimens exposed to the discharges showed that numerous radiation induced defects such as dislocation loops and hydrogen clusters were formed. These are typical defects formed by low energy (< a few keV) hydrogen bombardment. Mo, Fe and Cr, which originated from Mo fixed limiters and the 304SS vacuum vessel walls, were deposited on the specimens. The deposition profile depended on the geometrical relationship with the main plasma and affected the internal damage of the specimens. It is worth noting that the density of the metallic impurities in the scrape-off layer was almost constant during the steady-state discharge and had no adverse effects on plasma confinement in the TRIAM-IM.

ISSN:1042-0150    

DOI:10.1080/10420159208219831

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Collision cascades initiated from high energy PKAs produce defect clusters in crystalline solids irradiated with fast neutrons or energetic ions. They will affect not only an early stage of microstructural evolution but that at high fluence by changing free defect survival rate. To elucidate fundamental processes of cascade damage evolution,in situobservation of microstructure in FCC metals under heavy ion irradiation has been carried out using a combined facility of a 400 kV accelerator and a 200 kV transmission electron microscope installed in the University of Tokyo, Tokai. Defect clusters produced by individual energetic ions are observed during irradiation to examine subcascade formation, interaction of point-defects from cascade damage and related point-defect processes.

ISSN:1042-0150    

DOI:10.1080/10420159208219832

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

FCC metals are irradiated with low-energy (∼ I MeV) and high-energy (∼ 100 MeV) ions at ≲ 10 K. After irradiation, thermal annealing experiments are performed up to 300 K. Anomalous reduction of stage-I recovery is observed in Ni and Pt irradiated with high-energy heavy ions. Radiation annealing by irradiation of 100 MeV iodine ions is studied in pre-doped Ni and Cu. Experimental results are analyzed by using a model which describes the production and selective radiation annealing of defects. Extraordinarily large cross sections for radiation annealing of stage-I defects are obtained in Ni. These results show that in Ni and Pt the energy transferred from excited electrons to lattice atoms through the electron-phonon interaction contributes to the annihilation of defects during high-energy heavy ion irradiation.

ISSN:1042-0150    

DOI:10.1080/10420159208219833

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The recoil energy spectrum of the irradiation from presently proposed intense high energy neutron sources for the development of fusion reactor materials deviates appreciably from that in the fusion environment. A wide variation of representative elements of defect structure evolution are quoted from the experimental results and analyses of irradiation with various energetic particles; electrons, ions and neutrons in fission reactors and fusion neutrons. After all the discussion on the influence of primary recoil energy spectrum, a strong warning is sent concerning the establishment of a neutron source without serious consideration of the problems arising from the difference in the recoil energy spectrum from that in the fusion environment. The establishment of a medium sized neutron source with a nuetron energy spectrum closest to that in the fusion environment is strongly recommended.

ISSN:1042-0150    

DOI:10.1080/10420159208219834

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

An X-ray topographic method for investigating migration of point defects is described as a summary of previous work carried out on self-interstitials in ice. Since the method presented is based onin situobservations of dislocation climb in a thick specimen, the advantages of synchrotron-radiation topography for this method is emphasized. It is shown that the diffusion coefficients of the point defects can be determined as functions of both temperature and pressure.

ISSN:1042-0150    

DOI:10.1080/10420159208219835

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

A series of studies on the partial X-ray diffuse scattering intensities from ternary alloys analysed through synchrotron radiation experiments has been reviewed. An intensity expression for the short-range order diffuse scattering has been developed, which is necessary in understanding the separation method of an observed X-ray diffuse intensity into partial intensities contributed from different origins. Techniques have been described in detail mainly concerning the Cu2NiZn alloy, which have shown the benefits of the anomalous scattering effect of synchrotron radiation. The negative partial intensity maximum for the Cu-Ni pair found in the Cu-Ni-Zn alloy has been discussed from the viewpoints of crystallography and thermodynamics. In addition, at the end of the paper, local atomic arrangements causing the diffuse scatterings have been discussed.

ISSN:1042-0150    

DOI:10.1080/10420159208219836

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor