Abstract: A high-temperature gas reactor control rod is provided that does not degrade the joining state between the control rod elements even when stress is applied thereto, and that can improve the safety of the high temperature gas reactor remarkably by improving the heat resistance thereof. The high-temperature gas reactor control rod has a plurality of control rod elements (1) each having a neutron absorber (7) between an outer cylinder (9) and an inner cylinder (8) that form a double cylindrical tubular shape, the control rod elements (1) joined to each other in a vertical direction, characterized by: a columnar support member (2) for supporting at least the neutron absorber (7), disposed in the inner cylinder (8); and joining means for joining to another control rod element (1), provided at least one of upper and lower ends of the support member (2).

Abstract: A high-temperature gas reactor control rod is provided that does not degrade the joining state between the control rod elements even when stress is applied thereto, and that can improve the safety of the high temperature gas reactor remarkably by improving the heat resistance thereof. The high-temperature gas reactor control rod has a plurality of control rod elements (1) each having a neutron absorber (7) between an outer cylinder (9) and an inner cylinder (8) that form a double cylindrical tubular shape, the control rod elements (1) joined to each other in a vertical direction, characterized by: a columnar support member (2) for supporting at least the neutron absorber (7), disposed in the inner cylinder (8); and joining means for joining to another control rod element (1), provided at least one of upper and lower ends of the support member (2).

Abstract: A crucible 1 made of a C/C composite material for use in single crystal pulling, the crucible 1 having a lateral cylindrical portion 11 and a bottom portion 12 integrally formed as multiple layers wound by a filament winding method, in which the first layer 2 as the innermost crucible layer, among the multiple layers, is wound such that carbon fibers form tracks passing the polar point O at the bottom 12, the second layer 3 wound on the outer surface of the first layer 2 is wound along tracks to form a first outer circular bottom 8 that extends outwardly from about a middle part of a raised portion 6 where the carbon fibers of the first layer 2 are localized to the polar point O, and the third layer 4 and the succeeding layers wound on the outer surface of the second layer 3 are wound respectively along tracks to form outer circular bottoms that extend stepwise outwardly from about the middle parts of the outer surfaces of layers situated inside the respective layers, and the top for the raised portion of the

Abstract: A crucible 1 made of a C/C composite material for use in single crystal pulling, the crucible 1 having a lateral cylindrical portion 11 and a bottom portion 12 integrally formed as multiple layers wound by a filament winding method, in which the first layer 2 as the innermost crucible layer, among the multiple layers, is wound such that carbon fibers form tracks passing the polar point O at the bottom 12, the second layer 3 wound on the outer surface of the first layer 2 is wound along tracks to form a first outer circular bottom 8 that extends outwardly from about a middle part of a raised portion 6 where the carbon fibers of the first layer 2 are localized to the polar point O, and the third layer 4 and the succeeding layers wound on the outer surface of the second layer 3 are wound respectively along tracks to form outer circular bottoms that extend stepwise outwardly from about the middle parts of the outer surfaces of layers situated inside the respective layers, and the top for the raised portion of the

Abstract: A high-purity carbon fiber reinforced carbon composite formed by a process which entails graphitizing a molded member packed with carbon fibers, which fibers are subjected to a purification process under halogen gas prior to being graphitized and prior to being packed with a matrix of carbon material, and the matrix of carbon material, the carbon fiber reinforced carbon composite having an impurities content of not more than 30 ppm in ash content and satisfies either or both of the following conditions for impurities: (1) V is not more than 0.12 ppm by ICP-OES; and (2) Fe is not more than 0.10 ppm by ICP-OES.

Abstract: Since the dense and high purity pyrolytic-carbon-coated layer is formed with a thickness of 10-100 &mgr;m on the surface of the C/C composite, even when metallic impurities of the inside C/C composite are 5-100 ppm in ash content, similar effects to those of a known crucible made of the C/C composite whose inside was subjected to high purification can be produced to achieve full applicability to the structural elements of the CZ apparatus. Also, since the process time required or the C/C composite itself to be subjected to the high purification can be shortened, the effect of reducing the manufacturing costs considerably can be obtained.

Abstract: The present invention is directed to a single crystal pulling crucible of carbon fiber reinforced carbon composite material formed by the filament windings by combination of axially reinforced layers as well as circumberentially reinforced layers, which combination is given in two or more sets, and to the producing method thereof. The circumferentially reinforced layers resist a force tending to exapand a drum portion of the crucible, and the axially reinforced layers resist a force tending to push down a bottom of the crucible. The axially reinforced layers extending from the bottom portion to the drum portion can be formed by at least either of a level winding of a contact angle of 0.degree. to 10.degree. with respect to the center axis and a poral winding, and the circumferentially reinforced layers in area adjacent to the drum portion out of the drum portion and the bottom portion can be formed by at least either of a parallel winding of a contact angle of 70.degree. to 90.degree.