JPH049274B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an in-core tube for testing nuclear reactor fuel that prevents leakage of radiation to the outside.

The in-core tube for reactor fuel testing is used to test the safety of fuel for fast breeder reactors that use sodium as a heat medium, and to perform irradiation tests on the behavior of the fuel under special conditions.

The outline of the in-core tube for reactor fuel testing will be explained with reference to FIG. This test provides fuel safety and irradiation tests under specific conditions. This special condition is given by the circulation conditions of the in-furnace sodium loop 8 which circulates within the in-furnace tube 4, and this circulation is performed by an annular flow path type linear induction electromagnetic pump 7. Reference numeral 2 denotes a sodium inlet, which absorbs the heat of the reactor core 3 and flows from the outlet 5 as shown by the arrow, transferring the absorbed heat to an external heat exchanger.

The conventional electromagnetic pump used in the furnace tube 4 has a core 11 concentrically supported inside an inner tube 12 by a spacer 13 to form an annular sodium flow path, as shown in FIGS. 3 and 4. A coil 10 and a stator 9 were fitted around the outer periphery of an inner tube 12, and high-temperature sodium was transferred as shown by the arrow.

In this electromagnetic pump, the coil 10 is heated to a temperature raised by high temperature sodium (approximately 600°C).
In order to prevent the insulating material (enamel) covering the coil from melting or peeling off due to thermal expansion of the coil, it is necessary to cool the coil, and the coil cooling method shown in Figure 2 is required. fan 14 for
The exhaust port 15 was necessary.

However, it is impossible to install such an electromagnetic pump equipped with a cooling fan in the small space of the furnace tube, and the electromagnetic pump must be installed outside the furnace, which inevitably causes damage to the inside of the furnace. The sodium loop had to be extended outside the reactor and pulled out.

As a result, radioactive sodium has to be discharged outside the reactor, which requires countermeasures.Furthermore, there is a high risk of radioactive contamination, which reduces reliability. Ta. In order to solve the above-mentioned problem of melting and peeling of the insulating material of the coil, the present inventor developed a coil for electromagnetic pumps that does not require cooling and can sufficiently withstand high temperatures (Japanese Patent Application No. No. 157761).

The present invention incorporates an annular flow path type linear induction electromagnetic pump using this electromagnetic pump coil inside the furnace tube, forms a sodium circulation circuit inside the furnace tube, and prevents sodium from coming out of the furnace. The present invention aims to provide an in-core tube for testing nuclear reactor fuel.

The in-core tube for reactor fuel testing of the present invention has a hollow core inserted concentrically inside the inner tube of an electromagnetic pump, and the sodium flowing into the inner circumference of the core is transferred between the inner tube and the core. An annular flow path type linear induction electromagnetic pump with an annular sodium flow path formed in the inner tube to guide the sodium flow into the annular gap between the outer tube and the sodium flow path provided concentrically with an annular gap is installed in the furnace tube. A sodium circulation circuit is formed inside the furnace tube by connecting the inner tube to the core of the annular flow path type linear induction electromagnetic pump. This system is characterized by the ability to test reactor fuel without drawing the circulation circuit out of the reactor.

Embodiments of the present invention will be described in detail below, but first an outline of the electromagnetic pump coil that was previously filed will be described.

In FIG. 5, the coil material 16 is formed by covering a core wire 18 with a heat-resistant insulating material 17. The heat-resistant insulating material 17 is made of heat-resistant and flexible quartz cloth, glass fiber, ceramic tape, or the like. As shown in the sectional view of FIG. 6, the core wire 18 is made of heat-resistant clad copper, which is covered with a thin plate 19 of a heat-resistant alloy such as stainless steel or nickel so as to enclose a copper material 20.

The coil material 16 having such a cross-sectional structure is wound around a bobbin 21 shown in FIG. 7, and is formed as a coil 24 for an annular flow path type linear induction electromagnetic pump as shown in a cross-sectional view in FIG. Reference numeral 23 in FIG. 8 is a filler, and the coil material 16 is formed and held by the bobbin 21, the stainless steel plate 22, and the filler 23.

Therefore, the core wire 18 of the coil material 16 is heat resistant, and the coil material 1
Since the thermal expansion of 6 is absorbed, the coil 24 does not require cooling even at high temperatures.

Now, the details of the embodiment of the present invention using a coil that does not require cooling as described above will be explained with the help of figures. Fig. 9 shows a vertical cross section of an annular flow path type linear induction electromagnetic pump installed in a furnace tube. In the figure, a hollow core 26 is inserted concentrically into an inner tube 25 to form an annular sodium flow path 29. A wire duct 27 is inserted concentrically into the inner peripheral portion of the core 26, and an annular sodium flow path 30 is formed. The wire duct 27 and the inner tube 25 are in a closed state at one end 33, and the sodium flow paths 29 and 30 are connected to the closed end 33.
It is communicated in Note that 28 is an outer tube. FIG. 10 is an enlarged sectional view taken along the line A-A in FIG. It was used for.

FIG. 11 shows the external appearance of the furnace tube 4, in which F is a heat exchange section, d is an expansion tank section, and l is an annular flow path type linear induction electromagnetic pump section. 1st
FIG. 2 is a longitudinal cross-sectional view of the elongated furnace tube shown in FIG. 11, shortened and enlarged to explain its internal structure in an easy-to-understand manner. In the figure, the electromagnetic pump part e is as explained in FIG. 9, 24 is a coil, 25
is the inner tube, 26 is the core, 27 is the wire duct, 28
is an outer tube, and 28 and 29 are sodium flow paths. 4
2 and 43 are filled with argon gas. 3
4 is an outer tube for the sodium flow path, and 35 is an inner tube for the sodium flow path.
5 is provided concentrically to form an annular sodium flow path 45, and this annular sodium flow path 45, the annular sodium flow path 29 of the electromagnetic pump, the inner peripheral portion 30 of the core 26, and the sodium flow path inner tube 3
5 are connected to an annular flow path type linear induction electromagnetic pump so as to communicate with each other. 37 is a fuel, 38 is an electromagnetic flowmeter, and 39 is a meltdown cup, which are arranged in the sodium flow path inner tube 35. Reference numeral 36 denotes a lower guide pipe of the impile loop, which is fitted concentrically to the sodium flow path outer pipe 34 in the loading portion of the fuel 37 and is connected to the reactor vessel 1 (the first
(See figure) Sodium flow path outer tube 3
A so-called heat exchange section F is formed in which the sodium flows along the outer surface of the annular sodium flow path 45 in the direction of the arrow, and this sodium cools the sodium flowing through the annular sodium flow path 45. In addition, 40
4 is a spacer provided at one end of the lower guide tube 36;
Reference numeral 1 denotes a projection provided at the bottom of the sodium flow path outer tube 34, and this projection 41 is fitted into a hole provided in the spacer 40, so that the sodium flow path outer tube 34 and the lower guide tube 36 are held concentrically. An annular sodium flow path 46 is formed.

Next, the operation of this embodiment configured as described above will be explained.

In FIG. 12, the electromagnetic pump is excited by energizing the coil 24, and the flow rate of sodium is adjusted by the amount of energization.

On the other hand, sodium flows through the annular sodium flow path 3.
0, 29, 45, flows from the meltdown cup 39 into the sodium flow path inner tube 35, passes through the electromagnetic flowmeter 38 and the fuel 37, further reaches the annular sodium flow path 30, and inside the furnace inner tube 4. Sodium circulates as shown by the arrow. In this sodium circulation process, heat exchange is performed with the sodium in the reactor vessel 1 flowing in the annular sodium flow path 46, and the temperature of the sodium flowing from the sodium inlet 2 in the reactor vessel 1 is is cooled to a temperature approximately equal to . In this way, by cooling the temperature of the sodium circulating within the reactor tube 4, the fuel 37 is placed under the same conditions as the fuel loaded into the reactor core 3.

In this way, the fuel 37 is operated under the same conditions as the fuel loaded in the core 3, and then taken out.
Fuel safety tests and irradiation tests on fuel behavior under special conditions are carried out.

As detailed above, according to the in-core tube for reactor fuel testing of the present invention, an annular flow path type linear induction electromagnetic pump is provided in the in-core tube to circulate sodium inside the in-core tube. Therefore, there was no need to draw out the sodium in the reactor tube outside the reactor, and the risk of radiation leaking to the outside was eliminated, making it possible to further improve safety.

In addition, there is no need for piping or auxiliary equipment to draw the sodium loop of the furnace tube out of the furnace, which reduces the amount of radiation-contaminated waste and improves safety in terms of environmental pollution. be.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a nuclear reactor to explain the sodium loop in the reactor, Figs. 2 to 4 show a conventional annular flow path type linear induction electromagnetic pump, and Fig. 3 is a longitudinal cross-sectional view of the coil portion, FIG. 4 is a cross-sectional view thereof, and FIGS. 5 to 8 are coils for electromagnetic pumps used in embodiments of the present invention.
Fig. 5 is an external view of the coil material, Fig. 6 is a cross section of the coil material, Fig. 7 is a perspective view of a bobbin for winding the coil material, Fig. 8 is a longitudinal sectional view of the coil, and Fig. 9 Figures 12 to 12 show examples of the present invention, Figure 9 is a longitudinal cross-sectional view of an annular flow path type linear induction electromagnetic pump manufactured for use in a furnace tube, and Figure 10 is an enlarged cross-section taken along the line A-A in Figure 9. 11 is an external view of the furnace tube, and FIG. 12 is a longitudinal cross-sectional view of the furnace tube, which is shortened and enlarged to explain the internal structure of the furnace tube in an easy-to-understand manner. 4... Furnace tube, 7... Annular flow path type linear induction electromagnetic pump, 8... Furnace sodium loop, 24... Coil, 25... Inner tube, 26... Core, 27... Wire duct, 28... Outer tube, 29, 30 ...Annular sodium flow path, 34...Sodium flow path outer tube, 35...Sodium flow path inner tube, 37...Fuel.

Claims (1)

[Claims] 1. A hollow core is inserted concentrically inside the inner tube of an electromagnetic pump in an inner tube for indirectly testing nuclear fuel by loading fuel into a sodium loop under the same conditions as the reactor fuel. and an annular passage type linear induction electromagnetic pump having an annular sodium passage formed therein so as to guide sodium flowing from the inner circumference of the core into an annular gap between the inner tube and the core, is provided in the furnace inner tube, An outer sodium passage tube and an inner sodium passage tube, which are arranged concentrically with an annular gap, are connected to the core and inner tube of the annular passage type linear induction electromagnetic pump, and fuel is loaded into the furnace tube. An in-core tube for reactor fuel testing characterized by: