[en] A two-dimensional (2D) measurement system for FRC plasmas based on spectroscopy and computed tomography has been developed. The features of this system are as follows: (1) fifty chord signals of plasma emission are collected using five ten-channel fiber optic arrays; (2) 2D emission intensity profiles can be reconstructed as a function of time with up to a 0.25 μs resolution; (3) the result has explicit physical meaning with the help of five grating monochromators; (4) the measurement wavelength is tunable over visible and ultraviolet regions, and the bandwidth is also variable (0.2-2nm). The authors first measured a translated plasma at the outlet of the source region in the FIX machine. Typical plasma parameters of the source plasma produced on the FIX machine were total temperature ∼ 200eV, electron density ∼6.4 x 10¹⁵ cm^-3, and a lifetime ∼80μs. The separatrix radius and the length of the plasma were about 4.5 and 70cm, respectively. Five photocollector arrays were placed azimuthally around the z-axis at interval angles of 55 ∼ 65 degree. The result of reconstructing a set of 2D and time-resolved profiles is given. Since the major aim of this measurement, however, is observation of equilibrium profiles, formation, gross instability, plasma end profiles, they are now trying to measure the 2D bremsstrahlung profile at the midplane in the source region. At the same time, they are improving the optical system to increase the sensitivity for future measurements in the confinement region where the plasma density will be at least 100 times lower than in the source. Additionally, a reconstruction technique for a 2D H_β emission profile is being developed

[en] The interaction of interstitial nitrogen with substitutional alloying elements has been studied by measuring the Snoek relaxation in very dilute Fe-X-N ternary alloys (X: V, Cr, Mn, Mo). Isothermal measurements by the sub-resonance forced-vibration technique have revealed characteristic influence of substitutional solutes on the Snoek relaxation, which can be understood as trapping of N atoms at neighbouring sites of X atoms. The interaction energy has been evaluated by comparing the relaxation profiles observed experimentally with those calculated theoretically. The values thus obtained are of the order of 0.1 eV, with the magnitude being larger for elements of smaller group numbers, and are similar to those in the γ and liquid phases

No abstract available

[en] The objective is to develop a method for demolition of surface concrete using electric heating of reinforcing steel bars. The heating method of this study is inductive heating of steel bars by creating a magnetic field induced by applying high frequency current to a coil. An advantage of the heating technique is that steel bars need not to be exposed. The results of the experiments of applying electrical inductive heating to the reinforced concrete specimens show that cracks appear in the concrete surface, thereby enabling easy demolishment of the surface concrete. (orig./HP)

[en] A measurement study has been conducted to make clear the atomizing characteristics of swirl injection type spray nozzles attached inside a commercial nuclear reactor container as the safety spraying device. Diameters of particles sprayed from the nozzles having great capacity and small pressure loss are distributed very widely, It has been found that such ordinary methods as the accepting one were not sufficient for measuring the particle diameters from such nozzles. Then, a test equipment was manufactured in which diameters of water spray particles and their distribution from the nozzles under specified conditions can be measured by the direct photographic method. By using the equipment, the instant pictures of the particles 100 to 2,000 μ in diameter flying through the hood slit were clearly taken by the camera with short focus lens with the aid of the flash light source. The distribution of the diameters corrected for the flow distribution and the particle velocity has been found to be subject to logarithmic normal. (author)

No abstract available

[en] Mitsubishi Electric is manufacturing the electrical equipment and instrumentation for the secondary coolant system of Japan's 'Joyo' experimental fast-breeder reactor, a national project now under construction. This article describes some of the major equipment of this system. The fast-breeder reactor is characterized by the use of sodium as the coolant, and design requirements differ in many respects from those of light-water-reactor systems. It also has a number of unique instrumentation systems not required by the light-water reactor. (author)

[en] This article describes the control system manufactured by Mitsubishi Electric in 1973 for the drive mechanism that inserts and withdraws the control rods of the pressurized-water reactor of the No.2 unit of Kansai Electric Power's Takahama Power Plant. The drive mechanism is the magnetic jacking type equipped with three coils, which are energized according to an appropriate timing pattern to move the control-rod drive shaft in or out as required. (auth.)

[en] A simple enzyme immunoassay procedure was developed for the quantitative determination of 254-nm uv-induced DNA damage in cells. With the use of specific antibodies to uv-irradiated DNA and horseradish peroxidase-conjugated antibody to rabbit IgG, the extent of damaged DNA in uv-irradiated rat spleen mononuclear cells was quantitatively measurable. Through the use of this method, the amount of damaged DNA present in 2 X 10(5) cells irradiated at a dose of 75 J/m2 was estimated to be 7 ng equivalents of the standard uv-irradiated DNA. In addition, when the cells, irradiated at 750 J/m2, were incubated for 1 h, the antigenic activity of DNA decreased by 40%, suggesting that a repair of the damaged sites in DNA had proceeded to some extent in the cells

No abstract available