摘要:
A fuel assembly in accordance with the present invention comprises a plurality of first fuel rods and a plurality of second fuel rods having a length shorter than a length of the first fuel rod, and these two kinds of fuel rods are arranged in a fuel rod array of 10 rows by 10 columns. Two water rods are arranged in regions capable of arranging 8 fuel rods. The second fuel rods are not arranged in the outermost tier of the fuel rod array. Which satisfies the following conditions, that is, B≧60 (Equation 1) 15≦n≦20(n: integer) (Equation 2) Awr/Ach≦0.149 (Equation 3) Lp/Lf≧11/24 (Equation 4) Awr/Ach≧(3.00×10−4×n2+6.00×10−4×n−1.2×10−2)×(Lp/Lf−1)+1.75×10−1 (Equation 5) Awr/Ach≦(8.63×10−4×n2−6.09×10−2×n+1.33×10−1)×(Lp/Lf−8.32×10−1) (Equation 6) where Awr is a total sum of horizontal sectional areas of said water rods, Ach is a horizontal sectional area of a coolant flow passage in a bottom portion of said fuel assembly, Lf is an effective fuel length of said first fuel rod, n is number of said second fuel rods, Lp is an effective length of said second fuel rod, and B (GWd/t) is an average burn-up.
摘要:
A fuel assembly included a plurality of fuel rods, fuel spacers for maintaining gaps between the fuel rods and a channel box. The channel box includes spacer support portions projecting inwardly from an inner surface of the channel box and supporting the fuel spacer in a transverse direction and creep deformation inhibition portions disposed at the lower end portion of the channel box and projecting inwardly. The distance between the spacer support portions disposed to oppose one another in a horizontal direction is smaller than the distance between the creep deformation inhibition portions opposing one another in the horizontal direction.
摘要:
An object of the present invention is to provide a boiling water reactor wherein two phase flow instability in a fuel assembly occurs scarcely.A bottom flow path is formed beneath a partition plate which is supported by control rod driving mechanism housings in a reactor pressure vessel, and coolant guide tubes which open beneath the partition plate stands perpendicularly on the partition plate. An upper end portion of the coolant guide tube is restrained at outer periphery by a fixing portion of a square grid, and a coolant entrance of a fuel assembly is connected through to the coolant guide tube.Pressure loss of the coolant decreases and flow instability of the coolant in the fuel assembly occurs scarcely, lowering of a critical power ratio at a pump trip can be suppressed.
摘要:
A transparent electrode 21 formed by the ITO film, an EC layer 22 of an optoelectronic comprising element, a reflecting film also serving an electrode thin film 23 and an insulating sealing film 24 are deposited on a rear surface of a transparent substrate 20 of a main member of a mirror 10. The transparent substrate 20 has dividing lines 15, 16 for dividing a mirror surface area into a main mirror surface area 11 of a certain curvature convex surface having a large radius curvature and a supplemental mirror surface area 12 of a gradually varied curvature convex surface having a gradually decreased radius curvature. The EC layer 22 and the reflecting film also serving the electrode thin film 23 are divided along the dividing line 16 by cutting the transparent electrode 21 so that a reflectivity can be independently controlled on the main mirror surface area 11 and the supplemental mirror surface area 12 to achieve a safe driving of an automobile.
摘要:
In a mirror housing integrally formed with a stay fixed to a vehicle, a tilting mechanism for tilting a prism mirror is formed by a horizontal bearing, full reflection position engaging grooves and partial reflection position engaging grooves formed on the inside surface of the mirror housing and a plate spring and, head light from a vehicle running in the rear can thereby be dimmed. A mirror surface adjusting mechanism for the prism mirror is formed by a support, a plate pivot and a cap support and a driver can adjust the prism mirror to a position where he can easily watch the prism mirror.
摘要:
A viewing system for a vehicle has a mirror body protruding from a side of a vehicle, a light collecting element collecting light coming from the a rear field of view of the vehicle, a reflection element for reflecting light collected by the light-collecting element to the inside of the vehicle toward a field of view of a driver, and a rotating unit for rotating the light-collecting element so as to repel water drops adhering to its surface.
摘要:
A back mirror has plural mirror surface areas of different curvatures disposed side by side or plural mirror surface areas disposed side by side to form discontinuous planes. The back mirror includes a dividing line having a light diffusion effect formed along a border portion of the plural mirror surface areas. The dividing line may be formed by projections and depressions having a light diffusion effect which are formed on at least one of a transparent substrate, reflecting film and a transparent thin film formed on the reflecting film.