Fuel assembly lower pipe seat for balancing flow rate of coolant at reactor core inlet

A technology for fuel assemblies and balancing cores, which is applied to reactor fuel elements, reactors, and greenhouse gas reduction, etc., can solve the problems of easy generation of lateral flow, increase the vibration and wear loss of fuel rods, and achieve uniform flow and reduce the risk of vibration and wear. , reduce the effect of lateral flow

Active Publication Date: 2015-04-22
SHANGHAI NUCLEAR ENG RES & DESIGN INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The disadvantages of the above-mentioned two types of existing lower nozzle designs are: lack of optimal design for balanced flow distribution
In the existing design of the lower pipe seat, the grid plate of the lower pipe seat adopts the same hole pattern and evenly distributed flow holes. Under this design form, the flow distribution of the coolant is still not uniform when it passes through the lower pipe seat and then distributed, which is easy to produce Cross flow, increased risk of fuel rod vibration wear loss

Method used

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  • Fuel assembly lower pipe seat for balancing flow rate of coolant at reactor core inlet
  • Fuel assembly lower pipe seat for balancing flow rate of coolant at reactor core inlet
  • Fuel assembly lower pipe seat for balancing flow rate of coolant at reactor core inlet

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Embodiment 1

[0039] like Figure 4 and Figure 5 As shown, the lower pipe seat 1 of the preferred embodiment of the present invention is composed of a square filter plate 5 , a lower grid plate 6 and a support frame 7 . Wherein the uppermost filter plate 5 mainly plays the role of filtering foreign matter, and is manufactured by plate machining or plate stamping. The filter plate 5 is composed of a frame, a round hole plate, a slat, etc. The periphery of the frame of the filter plate 5 matches the size of the lower grid plate, and is a square with a side length of about 180mm-220mm, a frame width of about 5-10mm, and a thickness of about 0.5mm. ~2mm. The circular hole plate of the filter plate 5 is divided into 9 pieces, and each piece is distributed with a circular hole with a diameter of about 5-7mm. The circular hole plays the role of preventing foreign matter on the one hand, and controls the flow , The thickness of the round hole plate is about 0.5 ~ 2mm. The slats of the filter p...

Embodiment 2

[0043] like Figure 7 As shown, the lower nozzle base 1 of the preferred embodiment of the present invention is composed of a lower grille 6 , a support frame 7 , and a filter strip 9 .

[0044] Wherein the lower grille 6 is manufactured by plate machining, is a square with a side length of about 180 mm to 220 mm, and a thickness of about 15 to 25 mm. The lower grille 6 is machined with circular water holes 8 with different apertures. like Image 6 As shown, the flow hole 8 has three different pore diameters. The flow hole 8 with a smaller pore diameter is set at the corresponding position of the large flow area 3, and the pore diameter is about 5-7mm; the pore diameter is larger at the corresponding position of the large flow area 4 A flow hole 8 with a diameter of about 9-14 mm; a flow hole 8 with a diameter of about 7-9 mm is set at the junction of these two areas. The filter strip 9 is manufactured by strip machining or stamping. The thickness of the filter strip 9 is ab...

Embodiment 3

[0048] The difference between this embodiment and Embodiment 2 lies in that the thickness of the lower grid plate 6 is different. The lower grille 6 adopts different thicknesses in different areas. like Figure 8 As shown, the lower grille 6 adopts a larger thickness, about 22-26 mm, at the corresponding position of the larger flow area 3, and adopts a smaller thickness, about 18-22 mm, at the corresponding position of the lower flow area 4. The lower grille 6 with the above structure not only improves the supporting strength, but also realizes the function of optimizing flow distribution. Thicker areas can adopt trapezoidal and circular structures as shown.

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Abstract

The invention discloses a fuel assembly lower pipe seat for balancing flow rate of a coolant at a reactor core inlet, and relates to the design field of pressurized water nuclear reactors. The fuel assembly lower pipe seat for balancing flow rate of the coolant at the reactor core inlet disclosed by the invention comprises a lower grating, a supporting framework and a filtering structure, wherein the lower grating is located at the upper part of the supporting framework, the filtering structure is located at the upper part or the lower part of the lower grating, a guide pipe hole used for mounting a fuel assembly guide pipe, an instrument pipe hole used for mounting a fuel assembly instrument pipe and a water flow hole group used for flowing the coolant and re-distributing the flow rate are formed on the lower grating in a penetration manner; aiming at the phenomenon of non-uniform flow rate distribution on the contour section of the lower part area of the reactor core caused by jet flow of a large water flow hole in a lower plate of the reactor core, the structural design is optimized to obtain more uniform flow of the coolant at the lower part of the reactor core.

Description

technical field [0001] The invention relates to the design field of pressurized water nuclear reactors, in particular to a fuel assembly lower nozzle for balancing the coolant flow rate at the core inlet. Background technique [0002] The fuel assembly of pressurized water nuclear reactor is usually composed of several fuel rods, guide pipe parts, instrument pipe parts, grid, upper and lower pipe sockets, etc. Among them, the lower pipe socket is an important part of the fuel assembly skeleton and is one of the main bearing parts of the fuel assembly. First, its reliability directly affects the safety of fuel assemblies in operation, transportation and operation. At the same time, the lower nozzle is also an important interface part, and its structural design has a direct impact on the operational performance of the fuel assembly and the compatibility with the reactor internals. As the inlet of the core coolant, the hydraulic performance of the lower nozzle is also one of t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C3/322
CPCG21C3/322Y02E30/30
Inventor 郑轶雄干富军何广进刘松丁捷周云清朱丽兵
Owner SHANGHAI NUCLEAR ENG RES & DESIGN INST CO LTD
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