JPS5944687A - Reactor core structural element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to core components of a fast smelting reactor.

[Technical background of the invention]

In a direct-to-air reactor, the flow rate of primary coolant to core components such as fuel assemblies and control rod assemblies is distributed according to the proportion of heat generation i of each core component, and the removal of each core component is I'm trying to heat it up.

However, in the case of a control rod assembly, for example, 40 to 60 of the primary coolant distributed to one control rod assembly flows outside the control rod protection tube, and this is a waste flow that does not contribute to heat removal. becomes.

For this reason, the cooling temperature at the exit of the control rod assembly is lower than the coolant temperature at the exit of the surrounding fuel assemblies (as much as 200°C lower in extreme cases), and the thermal stress of the upper core mechanism is low. There was a risk that the integrity of the reactor would be damaged, such as the increase in the size of the reactor.

[Purpose of the invention]

The present invention was made based on these circumstances, and
The purpose of this is to effectively utilize the primary coolant flowing outside the control rod protection tube, increase the coolant temperature at the outlet, reduce the difference in coolant temperature at the outlet of the surrounding fuel assemblies, and The purpose is to maintain the health of the furnace.

[Summary of the invention]

The reactor core component according to the invention is such that a cylindrical space is provided between the rack 9 tube and the control rod guide tube, and a plurality of cooling phase flow holes are provided in the peripheral wall of the control rod guide tube, and the cylindrical space is provided with a plurality of cooling phase flow holes. It is configured to house multiple fuel elements inside.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical +fu view of the core components, and FIG. 2 is a cross-sectional view taken along the line ■-■ of FIG. This fuel assembly #1 has the same external shape as that of other fuel assemblies (not shown), and an entrance nozzle 3 is attached to its lower end. It is configured to be inserted and supported upwardly.

Inside the trumpet tube 1, a tljlJ inner tube 9 is disposed with a cylindrical space 7 between the trumpet tube 1 and the trumpet tube 1. A large number of coolant distribution holes 1 are provided in the parapet of this control salary guide 9.
1 are perforated at equal intervals in the circumferential direction and the axial direction.

A fuel element support plate 13 is provided at the bottom of the cylindrical space 7, and above the support plate 13, a plurality of fuel element support grids 15 are provided at appropriate intervals. Inside the cylindrical space 7, these fuel element support plates 1 are provided.
3 and a fuel element support grid 15, a plurality of fuel elements 17 are arranged in the circumferential direction.

Furthermore, a control rod assembly 19 is provided inside the control rod guide tube 9.
are arranged so that they can be raised and lowered freely. This control rod assembly 19 has a plurality of neutron absorbing material elements 2 inside the control rod assembly 2.
3 is stored, and the upper end of the protection tube 21 is restricted. i
Control rod drive mechanism (not shown)
A handling head 27 for lifting is attached to the upper end of the control rod guide tube 9.
is attached.

With the core components configured as described above, the flow path force of the primary coolant 29 flowing through the entrance nozzle 3 branches into three after passing through the entrance nozzle 29.

In the first flow path 29, a coolant flow flows from the lower part of the protection tube 2 to the neutron absorbing element 23 and rises, and after removing heat from the neutron absorbing element 23, a coolant flow; It flows out into the cylindrical space 7 and out through the upper end of the ratchet tube 1.

Further, the second flow path 29B ascends through the gap between the control rod guide tube 9 and the protection tube 21, and removes heat from the protection tube 21 to the outside.

The third flow path 29C rises within the cylindrical nitrogen pipe 7 and completely removes heat from the fuel element 17.The second flow path 29C
B passes through the cooling phase flow hole 1 provided in the inner pipe 9, connects to the third I/L path 29C, and connects to the fuel suction thread 17.
This will contribute to heat removal.

L Tough >
By the time it flows out from the upper end of the trumpet tube 1, it becomes a round surface.

Therefore, the exit section (
In other words, the temperature T of the coolant 29 at the top of the cooling pipe J). ut will be expressed by the following equation.

However, ~Tin: Entrance nozzle inlet temperature PCB' Neutron absorber element calorific value Pfuel:
Fuel element calorific value Psus: Protective tube, wrapper tube original heat value W: Distributed flow rate for one core component α: Proportionality coefficient On the other hand, in the conventional control rod assembly, Ratz! Vf
Since the fuel element is not placed within T, the outlet section is cooled and heat-sealed. ut is 0, and the combustion element source Pfuel is the neutron absorber element calorific value P. R, Ministry of Protection, Ratsuno 9 tube calorific value p8
Tout is much larger than uFI, so Tout is To
It's obvious that UT Yoshiharu Katana 1 will be warm. Moreover, the calorific value PcR of the neutron absorber element 23 decreases as the control rod assembly 19 is withdrawn, and when fully withdrawn it is about 1/10 of that when fully inserted. Although the outlet coolant temperature will drop slightly, in the configuration of the non-embodiment, the heat generation of the fuel element 17 will increase depending on the amount of withdrawal of the control rod assembly 19.
On the contrary, the temperature of the outlet coolant does not decrease due to withdrawal of the control rod assembly 19. By increasing the number of fuel elements 17, the outlet coolant temperature can be brought closer to the coolant temperature at the outlet of the surrounding fuel assembly, and the temperature difference therebetween can be made about 50°C.

〔Effect of the invention〕

As described above based on the embodiments, according to the present invention, there is a tube fall air [i4] between the trumpet tube and the control rod guide tube.
In addition, a plurality of coolant flow holes are provided in the peripheral wall of the control rod guide tube, and in order to store a plurality of fuel elements in the cylindrical space, coolant flowing outside the control rod protection tube is provided. As shown in Figure 4, the effective use of the next cooling phase reduces the temperature difference between the coolant at the outlet of the surrounding fuel assemblies and the coolant temperature at the outlet of the surrounding fuel assemblies, thereby maintaining the integrity of the reactor. It is possible to provide core components that can be used.

[Brief explanation of drawings]

The figures show one embodiment of the present invention, in which Figure 1 is a vertical plan view of the core components, and Figure 2 is a sectional view taken along the line 1--2 of Figure 1. 1...Trumpet tube, 3...Entrance nozzle, 7.
... Cylindrical space, 9... Control rod guide tube, 1 No.... Coolant flow hole, 12... Fuel element, 19... Control rod assembly, 2 No.... Control rod protection tube , 23... Neutron absorber element, 29... Primary coolant. Applicant's agent Patent attorney Takeshi Suzue Examination 4 Figure 2

Claims (1)

[Claims] A cylindrical space '(I: a control rod guide disposed inside the trumpet tube) is formed between a trumpet tube with an entrance nozzle attached to its lower end and a trumpet tube having a plurality of coolant flow holes in the peripheral wall. A tube, a plurality of fuel elements housed in the cylindrical space, and a neutron absorber are disposed in the PI section of the control rod guide tube and are driven in the control rod guide tube. A reactor core component characterized in that it comprises a control rod assembly that moves and operates.