KR910003803B1 - Nuclear reactor - Google Patents

Abstract

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Description

Atomically

1 is a longitudinal sectional view of a nuclear reactor in accordance with the present invention.

FIG. 2 is a longitudinal sectional view of the Calandria and inner barrel of the reactor shown in FIG.

3 is a fragmentary plan view of the inner upper side seen from the direction III-III of FIG.

4 is a fragmentary plan view of the Calandria lower plate seen in the direction IV-IV of FIG.

FIG. 5 is a fragmentary plan view of the Calandria top plate seen in direction V-V of FIG.

6 is a fragmentary longitudinal cross-sectional view of the Calandria.

7 is a longitudinal sectional view of a reactor in which another embodiment of the present invention is used.

* Explanation of symbols for main parts of the drawings

15: container 19: head

23: entry nozzle 25: exit nozzle

27: Core 39: Karlandria

43: guide portion 54: lower support structure

56: upper support plate 58: cavity member

66: cylinder 78: flanger

89: ridge 101: drive rod

The present invention relates to a reactor, and more particularly, to a reactor in which coolant, which is water at a critical temperature and pressure, is circulated through a reactor core installed in a reactor vessel. The core contains fuel and is arranged in the lower region of the reactor vessel. In addition, the reactor includes a control rod assembly. The control rod assembly includes a control rod, support for the control rod, drive rods for a plurality of control rods, and other related components. The core with the fuel assembly is usually referred to as the interior bottom of the reactor, and the control rods and rod guides are called the interior top of the reactor. The control rod can be moved between the inner top and the recess or dumble in the core by the driving rod.

The control rods are mounted in clusters on the drive rods by spiders. Rod clusters (RCC) comprise rods having a high neutron absorption cross-sectional area. These clusters are used to reduce power or shut down the reactor and move between the core and their guides many times during the fuel cycle of the reactor. There are so-called gray control rods that have a lower neutron absorption cross-sectional area than the high-absorbance RCC, which acts as a load follower or controls or appropriately outputs the reactor. Graybong moves between the core and the guide more than the highly absorbent RCC during the fuel cycle of the reactor (usually 5,600). There is also a water substitution cluster (WDRC), the diameter of which is the same as that of the RCC. They are used to maintain a relatively high level of hard water coolant in the core during initial operation of the reactor and to remove the replacement rods during the later operation of the reactor to increase the amount of hard water coolant in the core. Such light-replacement rod clusters are usually in the core for the first 60% of the fuel cycle, and are raised upwards for the remaining 40% of the fuel cycle.

Usually the RCCs and gray rods in the cluster are carried by the cross support and move inside the hollow cross guides. This guide usually has a groove through which the coolant passes. WDRC is not so protected. Many such tubes can be tucked in a square or square guide with holes through which coolant passes. At the end of the fuel cycle, the WDRC enters into the perforated guide and remains. All guides are on the inside of the reactor.

The coolant flows vertically through the core and into the upper interior. The outlet nozzle of the vessel is installed between the upper ends of the interior to allow the coolant to flow horizontally. Coolant then flows laterally through the control rod assembly to pass through the nozzle. Normally, the vertical flow of coolant through the core has a speed of about 5 m / sec. The flow through the nozzle has a speed of about 15 m / sec, and the cross flow through an area above the interior will be 9-12 m / sec. At this speed, the coolant during the later stages of the fuel cycle causes the vertical member and especially the WDRC to vibrate.

Mechanisms that cause vibration include eddy phenomena, eddy current vibrations, fluid elastic interactions, and cavitation. Tubes have been provided for receiving and guiding the control rods, and support for the control rods in the Calandria structures installed directly above the core has been proposed. In Calandria, coolant from the core is delivered out towards the radial discharge nozzle, which is protected by a tube at a relatively high cross flow rate.

However, such calenderrias are complex because it is necessary to install a fairly large number of closely spaced tubes, one for each control rod. Many tubes also limit radial flow area, resulting in high flow rates and relatively large pressure drops.

It is therefore a primary object of the present invention to provide an arrangement having all the advantages of the Calandria design described without fault.

To this end, the present invention is directed to a reactor comprising a vessel and a reactor core supported therein, wherein the control rod assembly is movably supported in the vessel and guided by a vertical control rod guide device arranged in the plenum above the core, Connected to the control rod assembly to move the control rod into the core, the vessel has at least one inlet nozzle for supplying coolant to the core, and the coolant introduced after passing up the core passes through the guide and then The outlet nozzles installed on the sidewalls were flown: the calandria extends far enough apart across the vessel above the core, allowing the yoke member with multiple control rods to move in the gap between the calandria and the core, The ria receives the drive rods and between the upper support plate and the lower support structure The lower support structure has a hole for coolant that flows from the core to the axial direction, and the Calandria is radially open in connection with the outlet nozzle to allow the coolant to flow into the Calandria. It flows horizontally on the outer surface of the cavity member, characterized in that it is discharged through the outlet nozzle without colliding with the driving rod.

The invention will become more apparent from the following description of the preferred embodiment shown by way of example only in the accompanying drawings.

The reactor 11 comprises a pressure vessel having a cylindrical body 15 whose base is closed by a spherical bowl 17. The container has an assisting head 19 with a flange bolted to the body at the flange 21. The body 15 has a plurality of inlet nozzles 23 and outlet nozzles 25 distributed around the circumference. Usually there are four inlet nozzles 23 spaced in pairs between the four outlet nozzles 25.

In the lower region of the body 15 is a nuclear reactor core 27. The core includes a dimple 31 and a fuel assembly 29 for receiving a control rod (not shown). The fuel assembly 29 and the thimble 31 are mounted between the upper core plate 33 and the lower core plate 35. The control rod was installed in the cluster by the yoke member and also included a rod cluster (RCC) having a high neutron absorption cross section, a gray rod cluster having a low neutron absorption cross section, and a hard water displacement rod cluster (WDRC). The RCC serves to shut down the reactor or reduce the heat output. Gray clusters perform load tracking control. WDRC replaces the coolant in a dumble that does not accept the RCC-ized gray rod cluster. Such substitution takes place early in the reactor fuel cycle, ie during the first 60% of the fuel cycle.

The upper part of the body 15 includes an inner upper side 37 and a calenderia 39. The inner upper side 37 includes a vertical guide part 41 (FIG. 3) for RCC and gray control rod cluster, and a vertical guide part 43 for WDRC. The RCC and gray control rod clusters are mounted on cross-shaped structures 40, and the guides 41 for these rods are hollow cross cylinders. The guide portion 43 for the WDRC generally has a square or square cross section cut in corners and should be referred to strictly as an octagonal barrel. The side 38 of the WDRC guide 43 is surrounded by the protruding arms of the four guides 41 and extends parallel to these arms. The plates 45 are spaced vertically along the guide 43 together with the coaxial holes 47. The plate 45 serves as a support for the can wall 38, and the WDRC is guided through the hole 47. The vertical side walls 49 and 51 of the guides 41 and 43 are generally free of holes, but the guides are open up and down. It may have small holes 53 and 55 in guides 41 and 43 for the purpose of stabilizing or equalizing the pressure of the coolant.

Calandria 39 (FIG. 6) usually includes a lower horizontal support plate 54 (FIG. 4) and an upper horizontal support plate 56 (FIG. 5) with a vertical cavity member 58 supported therebetween. do. The cavity member 58 is usually tubes having an annular cross section. They are confined by fillet welding 60 (FIG. 6) in the counterbore 62 of the top plate 56 and penetrate the bottom plate 54. The common member 58 was tapered thinly where they joined the bottom plate 54. The lower plate 54 usually has an egg-shaped hole 64. Each cavity member 58 is surrounded by four holes 64. The plate 54 also has a pin hole 71 which serves as the center of the guides 41 and 43. The guide has a pin (not shown) that enters the hole 71 at the top.

The upper and lower plates 54 and 56 are annular and the cavity member 58 is uniformly spaced in the annular cylindrical volume defined between the plates 54 and 56. The plates are enclosed by sheath 66 (FIG. 6) and have a lower structure 68, which is a composite structure and includes openings 72 coaxial with, and spaced apart from, openings 61 in barrel 57. ) Is included.

A support cylinder or shell 74 extends from the upper support plate 56 and includes an upper cylindrical portion 76 and a flange member 78.

The inner upper side 37 and the calenderia 39 are contained in the barrel 57 (FIG. 2). The barrel 57 has a hole 61 below the top of the annular cylindrical shape and paired with the edge of the outlet nozzle 25 in contact with the hole 72 in the outer shell 66 of the Calandria. The barrel 57 has a flange 65 at the top and at the bottom the barrel 57 supports the upper core plate 33.

The guides 41 and 43 are concentrated except near the periphery. So the coolant flowing in the gap between the guide portion in the core 27 has a height and tries to flow toward the surroundings. The pressure of the coolant decreases from the base to the top of the inner upper side 37. A horizontal forming plate 67 opens the barrel 57 to prevent the coolant under pressure from flowing sideways between the closely spaced guides 41 and 43 and a relatively free volume around the inner upper side 37. Extend along.

The core 27, the inner upper side 37 and the calenderia 39 are enclosed in the outer barrel 81. The lower core plate 35 is provided at the lower end of the barrel 81. The barrel 81 has a flange 85 at its upper end. The barrel 81 has an opening coaxial with the contact outlet nozzle 25 and located in mating fashion with the opening 61 in the Calandria sheath 66.

The core 27, the inner upper side 37 and the calenderia 39 are usually coaxially mounted.

The upper core plate 33 has pins 87 (first and second degrees) that restrain and center the fuel element 29. The cylinder 76 and the shell 60, the barrel 57 and the barrel 81, etc., are normally coaxial with the core 27, the inner top 37 and the calenderia 39. The flange 85 rests on the ridge 89 at the inner surface of the body 15. The flange 65 of the barrel 57 is above the flange 85 and a spring (not shown) is inserted between these flanges. The flange 78 is provided on the flange 65. The sheath 66, the barrel 57 and the barrel 85 are circumferentially arranged so that the boundaries 91 and 93 of the openings 72 and 61 are mated with each other, and the openings ( The border 93 (FIG. 1) of 61 is mated with the border 95 of the opening in the barrel 81, and the border 95 of the opening in the barrel 81 is the inner border of the outlet nozzle 25. Paired with (97). The annular strip 99 between the barrel 81 and the body 15 provides a passage between the inlet nozzle 23 and the lower end of the core 27. The coolant passing through the inlet nozzle 23 flows downstream into the bowl 17 through the annular band 99. From there it rises straight up through the core 27 and straight up to the Calandria 39 which flows laterally to pass through the exit nozzle 25 through the inner upper side 37. The connection point between the boundaries 91, 93 and 93, 95 and also between the boundary 95 and the border 97 is pressure sealed at the outlet nozzle from the annular band 99 through the outlet nozzle 25. Minimize or eliminate the ash bypass flow.

As shown, the outlet channel of the outlet nozzle 25 is just above the inner top, where the coolant passing through the Calandria flows directly into the outlet nozzle 25 at the level of the cavity member 58 of the actual Calandria 39. . The lower plate 54 of the calandria 39 is connected to the top of the inner upper side 37 and the coolant passes through the openings in the guides 41 and 43 and through the space between the guides. And flows through the gap between the forming plate 67 and the inner periphery 69 on the inner side. Calandria 39 serves as an upper support for the inner upper side. Drive rod 101 for control rods (FIG. 5) passes through the hollow member of the Calandria and prevents coolant from flowing out of highway exit nozzle 25 by these members.

Calandria's cavity members 58 and plates 54 and 56 are made of stainless steel. Typically the diameter of the outlet nozzle is about 1 m. The outer diameter of the cavity member 58 is usually 8.8 cm, the inner diameter is 5.5 cm and the length is about 125 cm. The cavity member 58 of this structure, supported by the plates 54 and 56 at both ends, minimizes the stress generated by the lateral flow of the coolant, which is almost 13 m / sec, to prevent the member from becoming damaged. do.

While preferred embodiments of the invention have been described herein, many modifications are possible there. For example, it is possible to place the discharge nozzle at the bottom plane level to reduce the height of the vessel and also allow the reactor coolant to have a more uniform radial outflow through the Calandria but with a greater pressure drop. Such an arrangement is shown in FIG. 7 and functionally similar components are indicated by numbers according to FIG. As shown in FIG. 7, the carlandria has a funnel shape in which the flow cross section increases radially outward. This causes the coolant flow rate where the flow direction rotates down toward the outlet nozzle 25 to be significantly reduced. However, in both arrangements, the control rods and control rod drives are protected from the outflow of coolant flow. In the Calandria where such an overlying flow takes place, there is no radial flow and there is only an axial flow independent of the vibration of the rod because the drive rod is installed in the connection protection tube and in the lower Calandria region.

When arranged on the rod cluster, ie when removed from the core, when arranged on the rod clusters, the Calandria is in proportion to the amount of control rods compared to the Calandria structure arranged directly on the core 27 which requires a tube for each control rod. Note that a corresponding relatively small amount of tube is required.

As shown in FIG. 7, the outlet nozzle 25 is located lower than the Calandria 39 so that the radial coolant flow from the Calandria is first passed through the annular space 160 before entering the radial outlet nozzle 25. Rotate to

In this arrangement, the radial outflow in Calandria is more uniform but the flow must rotate down on the periphery of the Calandria and then again out towards the outlet nozzle 25. As shown in FIG. 7, the Calandria has the form of upper and lower plates 181 and 161 so that the space 163 between 161 diverges in the flow direction, and the coolant flow on the outer periphery of the Calandria is relatively at the point of rotation. Relatively slow to produce a small amount of pressure drop. Also in the arrangement of FIG. 7, the carlandia shown is supported on the lower support plate 181 and extends to the reactor head 19 which makes it possible to use a reactor vessel of lower height than in the arrangement shown in FIG. 1. You should know that

Claims (10)

The inflow coolant raised up through the core 27 flows through the guide portion 43 to the outlet nozzle 25 installed on the side wall of the vessel 15, and the vessel 15 is configured to supply the coolant to the core 27. Having a drive rod 101 connected to the control rod assembly to move the control rod into and out of the core 27 and movably supported within the vessel 15, having at least one inlet nozzle 23 and above the core 27 In a reactor comprising a control rod assembly guided by a vertical control rod guide 43 arranged in a plenum of the reactor, a reactor core 27 supported in the vessel 15, and a vessel 15, the core 27 The calandria 39 extends far enough across the vessel 15 above, and the calandria 39 accommodates the drive rod 101 and between the upper support plate 56 and the lower support structure 54. A plurality of cavity members 58 are provided, wherein the lower support structure 54 is a core 27. There is a hole for the coolant flowing upward in the axial direction, and the Calandria 39 is radially opened to connect with the outlet nozzle 25 so that the coolant flowing into the Calandria 39 does not collide with the drive rod 101 without being collided. A reactor, characterized in that it flows laterally on the outer surface of the member (58) and is discharged to the outlet nozzle (25). The reactor of claim 1, wherein the outlet nozzle (25) is spaced with respect to the Calandria and there is no substantial pressure drop between the coolant flowing in the Calandria and the coolant flowing into the outlet channel. A reactor as claimed in claim 1, wherein the lower support structure (54) supports a lower end of the cavity member (58) and has an opening in the area between the cavity members (58). 2. The cylinder land (39) of claim 1 comprises a support cylinder (66) having a flange (78) at the top, wherein the flange (78) of the cylinder (66) is the body (15) and head of the reactor vessel. A reactor characterized by being bound between (19). 5. The container head according to claim 4, wherein the container head has an internal ridge (89), and important portions of the guide portion (37), the core (27) and the calenderia (39) are provided with a first flange installed on the ridge (89). It is surrounded by a first barrel (81) having a (85), wherein the guide and the carlandia are by a second barrel (57) having a second flange (65) installed on the first flange (85). Enclosed, the Karlandia has its flanges 78 installed on the second flange 65, and the first, second and Karlandia flanges 85, 65 and 78 have the ridge 89 and the container head. A reactor characterized by being squeezed in between (19). 2. The outlet nozzle (25) according to claim 1, characterized in that the outlet nozzle (25) enters the outlet nozzle (25) in a radial line with the calandria (39) without the radial outflow flow of the coolant from the calandria (39). Reactor. 4. The outlet nozzle (25) according to any of claims 1, 2 or 3, wherein the outlet nozzle (25) is arranged in a vessel below the Calandria (39) and the annular flow passage (160) from the Calandaria (39) to the outlet nozzle (25). A reactor provided between the circumference of the calenderria 39 and the outlet nozzle 25 for delivering the coolant. 8. The reactor of claim 7, wherein the upper and lower horizontal Calandria plates 161 and 181 are shaped to define a radially outwardly flowing flow path whose cross-sectional area increases toward the periphery of the Calandria 39. . 2. The reactor according to claim 1, wherein the calenderia (39) is supported at its lower support plate (181) and extends to the reactor vessel head (19). The reactor according to claim 1, wherein the Karlandria (39) serves as an upper support for the upper side of the reactor.

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