[en] An arm support is disposed to a lifting device disposed above a shielding body of a BWR type reactor. A telescopic multi-joint arm is attached rotatably to the arm support and a cutter is attached to the top end thereof. The cutter is placed to an optional position of biological shielding concrete walls in reactor shieldings by a remote control while extending and rotating the arm and the biological shielding concrete walls are cut. Then, the cutter is replaced with a dismantled piece gripping machine and dismantled pieces are gripped and taken out by the dismantled piece gripping machine by the operation of the arm. This can widen the cutting range of activated biological shielding concrete walls, and make the dismantling operation efficiently and shorten the operation term for dismantling. (I.N.)

[en] Purpose: To enable to attain the operation on a cylindrical coordinate system thereby performing dismantling operation exactly and at a high reliability. Constitution: A reactor dismantling robot is suspended by ropes by an elevating device to the inside of reactor shielding walls. The robot has a fixed portion having a plurality of legs abutting against the inner surface of the shieling walls while extending and shrinking radially in the horizontal direction and an arm portion having an operation arm disposed with a shielding wall breaking operation device. The arm portion is disposed with a mechanism for vertically moving the operation arm and a mechanism for forwarding and backwarding the operation arm in the horizontal direction and the arm portion itself is constituted so as to be rotatable around a vertical axis. (Seki, T.)

[en] High-resolution observations of the core region of the W3 molecular cloud using the (C-13)O emission as well as HCO+ and HCN emissions are reported. A high-resolution map of the optically thin (C-13)O emission is presented which is free from the self-reversal at V(LSR) = -39 km/s and which clearly reveals the detailed structure and the velocity field of W3 core. The complicated velocity field seen in the core is resolved into the relative and internal motions of the two condensations. 27 refs

[en] The concrete structures for nuclear reactor facilities are designed by taking the aseismatic capability and others in consideration, and are constructed very solidly. The main shields surrounding nuclear reactors are the composite object of concrete and steel, in which the concrete section is thick, the reinforcement of large diameter is arranged densely, steel lining is applied to the inner surface, and pipings are buried, accordingly those have the structure which is hard to be dismantled. Further at the time of dismantling, their radioactivity makes it more difficult. As the method of dismantling the concrete structures of reactor buildings, the method of cutting into small pieces and removing only the radioactivated parts, the method of carrying out a reactor body itself in a lump to outside, the method of jacking down a reactor body itself directly downward and burying it and others are conceivable. In all cases, safety must be assured for public and workers. The example of carrying out in a lump the research reactor JRR-3 in 1986 and the example of cutting and removing the power demonstration reactor JPDR currently in progress in Japan Atomic Energy Research Institute are reported. (K.I.)

[en] The present invention provides a method of de-voluming radioactive wastes by cutting and removing only the portions of side walls of biological shielding walls in a nuclear power plant that are contaminated by radioactivity. That is, vertical holes are formed each at a predetermined distance along a boundary between activated and not activated portions of the walls of the biological shielding walls by a boring machine. Then, a cut face is formed vertically in a radial direction by a wire saw utilizing the vertical holes. Subsequently, a cut face is formed vertically along a cylindrical face of the boundary by the wire saw utilizing the vertical holes. Next, a horizontal cut surface is formed by the wire saw. With such procedures, the activated inner side walls can be cut and removed succeedingly as blocks each of a predetermined size. As a result, since only the activated inner circumferential portion of the biological shielding walls can be cut and removed in the manner as described above by using the wire saw, the volume of the radioactive wastes can be reduced. (I.S.)

[en] From observations of the 53α H and He lines, gathered with the 45-m telescope at the Nobeyama Radio Observatory, we determined the helium to hydrogen abundance ratio by number, N(He)/N(H). For the Orion Nebula it amounts to 0.099 ± 0.008, where a correction for neutral helium based on optical observations is included; while for M17 it amounts to 0.108 ± 0.004. The M17 value, combined with optical O/H data for M17 as well as with optical observations of H_II regions in the SMC and in NGC 2366, implies that the helium to heavy elements enrichment by mass, ΔY/ΔZ, is equal to 3.6 ± 0.6. (author)

[en] The balloon observation of the infrared spectra of red giants and super giants was performed to investigate their energy flux in the near-infrared region of 0.9 - 2.5 μm. From this observation, the physical parameters of low temperature stars were determined, and their atmospheric structures were studied. The infrared detector was a PbS cooled by a thermo-module, and the I, J. H. Ω and K band filters were employed as spectrometers. Seventeen red giant infrared stars were observed in the above five bands of wavelength. Particularly, the energy fluxes of g Her and T Cep, which are M type late stars, were lower than those of early type stars. It indicates the existence of water vapor on these M type late stars. It is scheduled to launch the Fourier spectrometer in the next balloon experiment to observe precise near infrared spectra. (Yoshimori, M.)

[en] 22 years have passed since the first commercial nuclear power plant operation in Japan. At present, there were 33 commercial nuclear power plants in operation, supplying about 25 percent of total electricity. Some of them are going to be terminated in the near future and enter into the decommissioning stage. Therefore, it is now necessary to developed decommissioning technologies, including dismantling techniques of these power plants. The development of a concrete cutting machine is one of the most important items applicable to dismantling biological shield walls of the plants. This paper describes the outline of the cutting machine developed for the biological shield wall demolition of the Japan Power Demonstration Reactor (JPDR) including actual decommissioning works tested. (author)

[en] The authors report infrared spectroscopy of fluorescent emission of interstellar molecular hydrogen, the dominant constituent of the interstellar matter in the Galaxy. The data reveal for the first time the detailed level population of molecular hydrogen which is excited via absorption of interstellar ultraviolet radiation followed by fluorescent cascade. The ortho/para ratio appears to be significantly different from three, the high-temperature equilibrium value. This observed ratio may reflect the formation process of molecular hydrogen in the photodissociation zone on the surface of a molecular cloud, and would carry valuable information on the formation mechanisms of interstellar molecular hydrogen

[en] A sawing and coring technique has been developed to dismantle a biological shield in the JPDR decommissioning program. Preliminary cutting tests were conducted, using a prototype machine equipped with sawing and coring units to obtain data for characteristics of cutting, as well as to confirm applicabilities of this technique for reinforced concrete. Many data including cutting rates under various cutting conditions and characteristics of by-products were obtained in the tests. Based on the results of the cutting test, the dismantling system was designed for safe and efficient dismantlement of the JPDR biological shield. The actual dismantling work was performed from 1990 to 1991 and completed satisfactorily. (author)