Abstract: An underwater laser processing apparatus includes an optical unit and a nozzle. The optical unit irradiates a condensed laser beam generated by a YAG laser source to a certain point on a underwater workpiece. The nozzle has a gas exit for supplying a gas to the certain point. In the nozzle, an area surrounding the gas exit extends to the surface of the workpiece. This area keeps the supplied gas between the nozzle and the workpiece to improve the underwater laser process.

Abstract: A low-temperature-slush-fluid producing apparatus capable of achieving an increased weight solidification rate of slush fluid is provided. A low-temperature-slush-fluid producing apparatus includes a slush-fluid producing unit that includes a heat exchanger having a heat-transfer surface and disposed in a liquid-phase low-temperature fluid L stored in a container and scraping means for scraping a solid-phase low-temperature fluid formed on a surface of the heat-transfer surface; and a cryogenic-fluid generating unit for supplying into the interior of the heat-transfer surface a cryogenic fluid having a lower temperature than the liquid-phase low-temperature fluid L stored in the container.

Abstract: A repair method for a structure having an open flaw in a welding heat affected portion, including, removing at least a part of the open flaw and thereby forming a concave portion in the welding heat affected portion, forming build-up weld layers so as to fill the concave portion, treating a surface of the build-up layers to reduce tensile residual stress by means of at least one of laser peening, shot blasting and water jet machining. Also disclosed is an apparatus suitable for carrying out the repair method.

Abstract: An underwater laser processing apparatus includes an optical unit and a nozzle. The optical unit irradiates a condensed laser beam generated by a YAG laser oscillator to a certain point on a underwater workpiece. The nozzle has a gas exit for supplying a gas to the certain point. In the nozzle, an area surrounding the gas exit extends to the surface of the workpiece. This area keeps the supplied gas between the nozzle and the workpiece to improve the underwater laser process.

Abstract: An underwater laser processing apparatus includes an optical unit and a nozzle. The optical unit irradiates a condensed laser beam generated by a YAG laser source to a certain point on a underwater workpiece. The nozzle has a gas exit for supplying a gas to the certain point. In the nozzle, an area surrounding the gas exit extends to the surface of the workpiece. This area keeps the supplied gas between the nozzle and the workpiece to improve the underwater laser process.

Abstract: A method for manufacturing a control rod of a nuclear reactor, the control rod comprising a blade including neutron absorbers and a sheath, a tie rod for fixing the blade, a handle and a lower blade fixed to the tie rod and the blade. The method comprises a first step for cutting weep holes for water to cool the neutron absorbers in the sheath and cutting a periphery of the sheath, a second step for bending the sheath cut in the first step to a C-shape, a third step for inserting the neutron absorbers in a bent portion of the sheath formed by bending in the second step, a fourth step for successively welding the blade to the tie rod, the blade to the handle and the blade to the lower blade, and a fifth step for finishing portions welded in the fourth step.

Abstract: A method for manufacturing a control rod of a nuclear reactor, the control rod having a blade including neutron absorbers and a sheath, a tie rod for fixing the blade, a handle and a lower-blade fixed to the tie rod and the blade. The method includes a first step for cutting weep holes for water to cool the neutron absorbers in the sheath and cutting a periphery of the sheath, a second step for bending the sheath cut in the first step to a C-shape, a third step for inserting the neutron absorbers in a bent portion of the sheath formed by bending in the second step, a fourth step for successively welding the blade to the tie rod, the blade to the handle and the blade to the lower-blade, and a fifth step for finishing portions welded in the fourth step.

Abstract: A repair method for a structure having an open flaw in a welding heat affected portion, including, removing at least a part of the open flaw and thereby forming a concave portion in the welding heat affected portion, forming build-up weld layers so as to fill the concave portion, treating a surface of the build-up layers to reduce tensile residual stress by means of at least one of laser peening, shot blasting and water jet machining. Also disclosed is an apparatus suitable for carrying out the repair method.

Abstract: An underwater laser processing apparatus includes an optical unit and a nozzle. The optical unit irradiates a condensed laser beam generated by a YAG laser oscillator to a certain point on a underwater workpiece. The nozzle has a gas exit for supplying a gas to the certain point. In the nozzle, an area surrounding the gas exit extends to the surface of the workpiece. This area keeps the supplied gas between the nozzle and the workpiece to improve the underwater laser process.

Abstract: An in-pipe work device comprising at least two movement mechanisms connected with each other in a longitudinal direction of a pipe by a flexible tube, and a control device for controlling the movement mechanisms, the movement mechanisms including a body connected to the flexible tube, a guide member installed on the body such that the guide member is slidable in an axial direction, a support leg drive mechanism provided on the guide member and having a support leg movable in a radial direction of the pipe, for pressing the support leg against an inner wall of the pipe, thereby to hold the guide member kept unmovable in an axis direction of the pipe, a slide mechanism for relatively sliding the guide member and the body, with the support leg pressed against the inner wall of the pipe, thereby to slide the body in the axis direction of the pipe, wherein the control device controls the in-pipe movement device so as to move in a pipe by itself, by sequentially operating the plurality of movement mechanism in a pr

Abstract: Optical paths of laser beams generated from at least two laser beam generators, which are used for performing connection and cutting work at prescribed locations of structural members, are each switched by corresponding optical path switchers, and the laser beams polarized by the corresponding optical path switchers are reflected in the same direction by a laser beam combiner to combine the plurality of laser beams into a parallel laser beam bundle, in order to perform cutting or welding at the corresponding prescribed location. This configuration removes the need to provide high-power laser beam generators for situations such as vacuum walls of fusion devices where the laser generation efficiency is low, while also making it possible to use more powerful high-power lasers therein if necessary.

Abstract: A surface heat-treating apparatus which focuses laser beam onto a surface of a workpiece for heat-treating the same comprises a composite cylindrical segment mirror and a cylindrical mirror provided in a subsequent stage thereof. The composite mirror is made of two cylindrical segment mirrors joined together with a predetermined angle in a V-shaped manner so that the laser beam reflected by the two component cylindrical segment mirrors of the composite mirror is transmitted to the cylindrical mirror in a manner reversed with respect to the lengthwise and widthwise directions of the composite cylindrical segment mirror and a heat-treating area of a rectangular configuration is thereby provided on the workpiece.

Abstract: The present invention is directed to improvements in an automatic pattern reading apparatus of the type which comprises a light source for illuminating an object pattern, an imaging unit for receiving the illumination light reflected by or transmitted through the object pattern and a drive unit for one- or two-dimensionally moving said object pattern or said imaging unit. The improvement comprises means for detecting the leading edge position of said object pattern by means of the output picture signal from said imaging unit, means for detecting the trailing edge position of said object pattern, area detection means for detecting an area including the area defined by the leading and trailing edge positions and the area surrounding said defined area and characteristic extract means for extracting the characteristic amount of said object pattern by means of picture signal derived from the detected area.