RU2473991C1 - Nuclear reactor core - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: nuclear reactor core comprises fuel assemblies with guide channels, absorber rods of a control and protection system, with a head and absorbing elements with a shell. On the external surface of the absorbing element shell there is at least one diametrical bulge arranged in the upper part of the absorbing element, which enters the guide channel, whenever the absorber rod falls.

EFFECT: reduced dynamic forces at elements of a fuel assembly and an absorber rod.

3 cl, 5 dwg

Description

State of the art

Known active zone [1], containing fuel assemblies, incorporating guide channels and regulatory bodies of the control and protection system, incorporating absorbing elements. Absorbing elements are made in the form of smooth tubes filled with an absorber. The guide channels are also made in the form of smooth pipes. Absorbing elements are suspended on a special head and their movement occurs in the guide channels of the fuel assembly. When emergency protection is triggered, the absorbent rod falls on the fuel assembly head. The energy of the fall is extinguished by the spring block of the fuel assembly and the suspension springs of the absorbing elements. The disadvantage of this design is that as a result of the fall of the regulatory bodies of the control and protection systems, shock loads are transferred to the cartridge elements. The head of the absorbing rod must also withstand the same loads, which requires an increase in the height of the ribs of the head.

Known active zone [2], containing fuel assemblies, incorporating guide channels and regulatory bodies of the control and protection system, incorporating absorbing elements. Absorbing elements are made in the form of smooth tubes filled with an absorber. The guide channels are also made in the form of smooth pipes. Moreover, in the lower part, the inner diameter of the guide channels is made with a smaller diameter. When emergency protection is triggered, the movement of the absorbing elements occurs in the guide channels of the fuel assembly. At the end of the fall, the movement of the lower part of the absorbing elements occurs in the guide channels with a smaller inner diameter. Thus, increased hydraulic resistance is created, due to which the drop energy is extinguished. The disadvantage of this design is that a compressive load is created on the shell of the absorbing elements, which can lead to a change in the shape of the absorbing elements and the unreliability of the emergency protection.

The closest analogue in the set of essential features with the proposed invention is a fuel assembly [1], which is what we choose for the prototype.

Disclosure of invention

The aim of the invention is to increase the reliability of the control and protection system and the ability to increase the life of the PS CPS.

The objective of the invention is to optimize the hydraulic characteristics of the movement of absorbing elements in the channels of the guides of the fuel assemblies and, in this regard, to optimize the stiffness characteristics of the spring block of the fuel assembly.

The technical result is to reduce the dynamic forces on the elements of the fuel assembly and the absorbing rod, the radiation resistance of which decreases during operation.

The specified technical result is achieved in that the active zone of a nuclear reactor contains fuel assemblies (1) with guide channels (2) and absorbing rods of a control and protection system (3) with a head (4) and absorbing elements (5) having a shell (6) . On the outer surface of the shell (6) of the absorbing element (5), at least one diametrical thickening (7) is made located in the upper part of the absorbing element (5).

Alternatively, the diametrical thickening (7) can be made in the form of at least one rib (8). In this case, the angle α of the inclination of this rib (8) to the axis of the absorbing element (5) can be nonzero.

Alternatively, the diametrical thickening (7) can be performed with a corrugated surface, providing increased hydraulic resistance.

Brief Description of the Drawings

The invention is illustrated by drawings, on which

figure 1 - the active zone with fuel assemblies and regulatory authorities;

figure 2 - absorbing rod;

figure 3 is a fragment of an absorbing element with one diametrical thickening;

4 is a fragment of an absorbing element with a diametrical thickening in the upper part;

5 is a fragment of an absorbing element with a diametrical thickening in the form of one rib, the angle α of which the inclination to the axis of the absorbing element is non-zero.

The implementation of the invention

The active zone of a nuclear reactor contains fuel assemblies (1) with guide channels (2), absorbing rods of the control and protection system (3) with a head (4) and absorbing elements (5) having a shell (6). On the outer surface of the shell (6) of the absorbent element (5), at least one diametrical thickening (7) is made located in the upper part of the absorbent element (5).

Alternatively, the diametrical thickening (7) can be made in the form of at least one rib (8), while the angle α of inclination of this rib (8) to the axis of the absorbing element (5) can be nonzero.

Alternatively, the diametrical thickening (7) is made with a corrugated surface.

The proposed core is as follows. During operation of the reactor, the flow of coolant passes through the guide channels (2) of the fuel assembly (1). The lower ends of the absorbing elements (5) of the absorbing rod (3) of the control and protection system are located in the guide channels (2). Moreover, between the wall of the guide channel (2) and the shell (6) of the absorbing element (5) there is a gap (9). When emergency protection is triggered, a fall occurs under the own weight of the absorbing rod (3) of the control and protection system. Each absorbing element (5) moves in the guide channel (2) in the oncoming coolant flow. At the end of the fall process, a diametrical thickening (7) enters the guide channel (2). There is a decrease in the gap (9) between the wall of the guide channel and the shell (6) due to the diametrical thickening (7). An additional hydraulic resistance is created to the movement of the absorbing elements (5), which leads to the appearance of an additional force directed upward, which reduces the impact on the absorbing rod (3) of the control and protection system and the elements of the fuel assembly (1). The fall energy of the absorbing rod (3) of the control and protection system is spent on changing the flow parameters of the coolant in the gap (9). The presence of corrugation on the diametrical thickening creates additional hydraulic resistance in the gap (9), which provides an additional opportunity for design optimization.

Thus, the load on the spring block (10) of the fuel assembly (1), and, accordingly, on the guide channels (2), is reduced. Also, the loads on the head (4) and the shell (6) of the absorbing rod (3) are reduced. Ultimately, this will reduce the overall characteristics of the spring block (10) of the fuel assembly (1). While maintaining the size of the fuel assembly (1), this solution will make it possible to increase fuel loading and optimize fuel cycles.

The introduction of this improvement allows us to optimize the hydraulic characteristics of the movement of absorbing elements in the guide channels.

The proposed solution on the set of essential features of the assembly of a fuel nuclear reactor has a novelty in comparison with the prototype.

The economic efficiency of the application of the invention is determined by the following:

- a decrease in dynamic loads on the head of the absorbing rod;

- an increase in core power in promising fuel cycles with increased efficiency in the use of nuclear fuel;

- increasing the reliability of emergency protection by increasing the weight of the incident absorbing rod and its kinetic energy.

Industrial applicability

It is most expedient to use the proposed solutions for operation in water-cooled nuclear power reactors.

1. Shmelev V.D., Dragunov Yu.G. Denisov V.P., Vasilchenko I.N. VVER core for nuclear power plants. - M.: IKC "Akademkniga", 2004. Chapter 6.

2. A.Ya. Kramerov. Questions of designing nuclear reactors. M .: Atomizdat, 1971, §8.2, Fig. 8.3

Claims (3)

1. The core of a nuclear reactor containing fuel assemblies (1) with guide channels (2), absorbing rods of a control and protection system (3) with a head (4) and absorbing elements (5) having a shell (6), characterized in that on the outer surface of the shell (6) of the absorbing element (5), at least one diametrical thickening (7) is made located in the upper part of the absorbing element (5). 2. The core of a nuclear reactor according to claim 1, characterized in that the diametrical thickening (7) is made in the form of at least one rib (8), while the angle α of inclination of this rib (8) to the axis of the absorbing element (5) can be nonzero. 3. The core of a nuclear reactor according to claim 1, characterized in that the diametrical thickening (7) is made with a corrugated surface.

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