JP2006064432A - Method for improving heat transfer performance from fuel rod to coolant, while decreasing flow resistance of fuel rod and in-core structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease a flow resistance of furl rods and in-core structure and improve heat transfer performance from fuel rods to coolant. <P>SOLUTION: The surface of fuel rods and in-core structure is provided with a multitude of dimples and/or projections such as pins or wires. In this manner, heat transfer performance from the surface of fuel rods and in-core structure is raised. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a method for improving the heat transfer performance to the coolant by processing the surfaces of the fuel rod and the internal structure of the furnace, and at the same time reducing the flow resistance of the surface of the fuel rod and the internal structure of the furnace. Is the method. More specifically, the present invention improves the heat transfer performance to the coolant by reducing the flow resistance of the surfaces of the fuel rods and the reactor internal structure by processing the surfaces of the fuel rods and the reactor internal structure. Thus, the cost can be reduced by reducing the size of the fuel rod and the core structure, and the cost of constructing the reactor including the circulation machine and the like can be reduced.

Conventional technology

  Conventionally, heat transfer to the coolant has not been improved by processing the surfaces of the fuel rods and the reactor internal structure. Furthermore, the flow resistance was not reduced.

  From the actual measurement data of the high temperature engineering test research reactor of the Japan Atomic Energy Research Institute, it was found that the heat transfer performance to the coolant was improved by processing the surface of the fuel rod and the internal structure of the reactor. According to the present invention, it is possible to reduce the costs related to the fuel rod and the in-furnace structure. At the same time, by reducing the flow resistance of the surfaces of the fuel rods and the reactor internal structure, it is possible to reduce the cost of constructing the reactor related to the coolant circulation machine. From the above, construction costs of all reactors can be reduced regardless of reactor types such as light water reactors, gas reactors, and breeder reactors.

  In order to solve the above problems, the present invention provides a fuel rod and a reactor internal structure by providing a number of dimples and / or protrusions such as pins or wires on the surface of the fuel rod and the reactor internal structure. This is a method for improving the heat transfer performance from the surface of the steel to the coolant.

  According to the present invention, the size of the fuel rod and the in-furnace structure can be reduced, thereby reducing the cost for construction. Furthermore, the flow resistance on the surfaces of the fuel rods and the reactor internal structure can be reduced, and the cost related to the coolant circulation machine can be reduced.

  A comparison between the prior art and the present invention (new technology) regarding the heat transfer performance and flow resistance of fuel rods and in-furnace structures is shown in FIG. In the prior art, fuel rods and furnace structures that are not processed on the surface are used, and coolant is circulated through them, but the heat transfer performance is not sufficient, The flow resistance was high.

  On the other hand, in the new technology relating to the present invention, heat transfer performance can be improved and flow resistance can be reduced by providing a large number of dimples on the surfaces of the fuel rod and the reactor internal structure. it can. As a result, it is possible to reduce the cost of reactor construction for the circulation machine and the like, and it is possible to reduce the size of the fuel rod and the reactor internal structure. As the surface shape of the fuel rod and the in-furnace structure in the present invention, not only a depression such as a golf ball but also a protruding shape such as a pin or a wire can be used.

  That is, in the present invention, (a) turbulent flow is intentionally generated on the surfaces of the fuel rod and the reactor internal structure, and the flow resistance can be reduced by moving the separation point, and (b) In this way, by intentionally generating turbulent flow on the surfaces of the fuel rod and the reactor internal structure, heat transfer performance can be improved by turbulent heat transfer. Further, since the size of the fuel rod and the reactor internal structure can be reduced by improving the heat transfer performance based on (b), the flow resistance of (a) can be further reduced.

  FIG. 2 shows a fuel compact, a fuel rod filled with the fuel compact, and a fuel body filled with the fuel rod. The fuel compact has a fuel nucleus (uranium dioxide) as a core, and the periphery thereof is covered with a laminate composed of a low-density pyrolytic carbon layer, a high-density pyrolytic carbon layer, and a silicon carbide layer. The fuel rod is constituted by filling a fuel compact into a cylindrical graphite sleeve, and an end plug is provided at the upper end thereof. The fuel body has a structure in which a fuel rod is inserted into a fuel rod insertion hole.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 shows an embodiment in which the method of the present invention is used.
For example, as shown in FIG. 1, by providing a large number of dimples on the surface of the control rod and the reactor internal structure, the heat transfer performance from the surface of the fuel rod and the reactor internal structure to the coolant is improved. In addition, the flow resistance can be reduced at the same time.

Of course, the present invention is not limited to the above examples. It goes without saying that various modes are possible for details such as the configuration, position and quantity of the recesses.
[The invention's effect]

  The coolant flows between the fuel rods filled in the fuel body to cool the fuel rods. However, in the present invention, a depression and / or a protrusion is formed on the surface of the graphite sleeve of the fuel rod and the surface of the fuel rod insertion hole of the fuel body. Therefore, the flow resistance can be reduced and the heat transfer performance from the fuel rod to the coolant can be improved.

It is a figure which shows the comparison of the fuel rod and reactor internal structure in this invention and a prior art. FIG. 2 is a view showing a fuel compact, a fuel rod filled with the fuel compact, and a fuel body filled with the fuel rod.

Claims (2)

  A method of improving the heat transfer performance from the fuel rod to the coolant by reducing the flow resistance by providing a depression and / or protrusion on the surface of the fuel rod. A method of improving the heat transfer performance from the in-furnace structure to the coolant by reducing the flow resistance by providing depressions and / or protrusions on the surface of the in-furnace structure.