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Spacer grids with springs having improved robustness

A positioning grid and cantilever spring technology, applied in the direction of climate sustainability, greenhouse gas reduction, reactors, etc., can solve the problems of spring plastic deformation, loss of fuel rod clamping force, spring deflection, etc.

Inactive Publication Date: 2015-04-01
BABCOCK & WILCOX MPOWER
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Unfavorable operating conditions can cause high accelerations on the fuel rods, which can cause excessive spring deflection
Springs deflected beyond normal fuel rod position may plastically deform and lose grip on the fuel rod
The spring may also bottom out allowing the fuel rods to contact the grid

Method used

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  • Spacer grids with springs having improved robustness
  • Spacer grids with springs having improved robustness
  • Spacer grids with springs having improved robustness

Examples

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Embodiment Construction

[0021] refer to figure 1 , shows an illustrative nuclear reactor 1 of the Pressurized Water Reactor (PWR) type. The illustrative PWR 1 includes a nuclear reactor core 2 disposed within a pressure vessel, which in the illustrative embodiment includes a lower vessel portion 3 and an upper vessel portion 4 connected by a central flange 5 . The reactor core 2 is disposed in the lower vessel portion 3 and includes fuel rods containing fissile material (e.g., 235 U). A cylindrical central riser 6 is arranged coaxially inside the cylindrical pressure vessel and a downcomer annular space 7 is defined between the central riser 6 and the pressure vessel. The illustrative PWR 1 includes an internal control rod drive mechanism (internal CRDM) 8 that controls insertion of control rods to control reactivity; however, the reactor may instead employ an external CRDM. In either case, the guide frame support 9 guides the translating control rod assemblies (e.g., each control rod assembly co...

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PUM

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Abstract

A spacer grid includes intersecting straps defining cells with springs and dimples arranged to hold fuel rods passing through the cells. The springs are dual cantilevered springs with a bridge section between the distal end of the spring and the base. The distal portion of the spring is less stiff than the bridge section. The bridge section creates a bump which acts as a stop or travel limiter to prevent loss of grip force due to excessive spring deflection.

Description

[0001] This application claims priority to US Provisional Application No. 61 / 625,164, filed April 17, 2012. US Provisional Application No. 61 / 625,164, filed April 17, 2012, is hereby incorporated by reference in its entirety. technical field [0002] The following relates to the field of nuclear fuel, the field of nuclear reactors, the field of nuclear power generation and related fields. Background technique [0003] A nuclear reactor core is typically configured as an array of fuel assemblies (FAs), where each FA is vertically coextensive with the height of the reactor core and the array of FAs spans the lateral dimension of the reactor core. each FA consists of a vertically oriented array of fuel rods held together by a structural frame consisting of a vertically spaced set of horizontal spacer grids welded to guide tubes or other rod-like vertical elements . The upper and lower ends of the FA are capped by upper and lower fittings (sometimes referred to as nozzles), wh...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C3/352
CPCG21C1/32G21C3/352G21C3/3563Y02E30/30
Inventor A·W·多恩L·A·沃尔顿G·S·帕必斯
Owner BABCOCK & WILCOX MPOWER