JPS5844384A - Fascia pannel for reducing heavy water in calandria tank - 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 The present invention relates to the reactor main body structure of a pressure tube type nuclear reactor, and in particular, to miniaturization of the reactor main body, shortening of the pressure pipe lower extension pipe,
The present invention also relates to a vertical downward fuel exchange type pressure tube reactor structure suitable for reducing heavy water in the convex portion of a power land rib tank.

In the conventional pressure tube type nuclear reactor, as shown in Fig. 1, the lower iron water shield 3 is installed on the reactor support shield wall 400. The thickness Xm of the wall 400 part becomes a dead space, and when the inlet pipe 301 is routed, the piping support 303, etc. are also taken into consideration, the length L of the lower extension pipe 304 of the pressure pipe assembly 300 becomes long, which reduces the productivity and maintenance. There are disadvantages such as the height of the containment vessel as well as the size.

Furthermore, since a reactor reactivity control method using a heavy water dump is adopted, there is a disadvantage that the diameters of the reactor body and containment vessel are increased by the dump space 201 of the calandria tank 200.

The objects of the present invention are: 1. By shortening the pressure pipe lower extension pipe,
It is an object of the present invention to provide a pressure tube type nuclear reactor main body structure in which the core position and containment vessel height are kept as low as possible, and earthquake resistance and economic efficiency are improved.

2. By eliminating the heavy water dump space in the calandria tank and reducing its diameter, the diameter of the reactor body and containment vessel can be reduced, thereby providing a pressure tube type reactor body structure that improves economic efficiency.

3. In relation to 2 above, it is an object of the present invention to provide a calandria tank structure that reduces heavy water in the convex portion of the calandria tank.

The present invention is characterized by: 1. In order to shorten the pressure pipe lower extension pipe, the core region of the lower iron water shield is positioned below the upper surface of the shield wall during reactor operation.

The configuration and functions of the reactor body will be explained based on FIGS. 2 to 5.

The container that houses the reactor core is the calandria tank 2.
It is called 00. The calandria tank 200 is a modified cylindrical container made of stainless steel, and the calandria tubes 202 made of Zircaloy are attached to the upper and lower tube plates 203 and 204 by an inner ring 205 by the rolled joint method, as shown in FIGS. 3 and 4.
are mechanically connected via. Heavy water from the reducer 206 is flowing into the calandria tank, and a pressure tube assembly 300 is inserted into each calandria tube 202 as shown in FIG.

The pressure tube assembly 300 accommodates the fuel assembly and serves as a path for coolant (light water) via an inlet pipe 301 and an outlet pipe 302. To replace the fuel assembly, replace the pressure pipe assembly 30.
The fuel exchanger 500 performs this from below.

Radiation from the reactor core is prevented by upper, side, and lower iron water shields 1 and 2°3 that surround the calandria tank 200, and a reactor support shield wall 400 provided outside of the shields. Upper, side and lower iron water shields 1, 2.3
It has a structure consisting of multiple layers of thick steel plates and water, and structurally constitutes a part of the reactor body, including the 200° upper part of the calandria tank, the sides, the iron water shields 1 and 2, and the pressure The tube assembly 300 is supported by the reactor support shielding wall 400 via the lower iron water shielding probe 3 .

The details of the load transmission path are as shown in FIG.

As shown in Figure 3, the vertical rigidity of the reactor body is determined by the upper tube plate 11 of the upper iron water shield, the lower tube plate 31 of the lower iron water shield, the upper tube plate 203 of the calandria tank, and the lower tube of the calandria tank. It is ensured by a quick-forming structure composed of four tube plates consisting of plates 204, upper ferrous sleeve 12, lower ferrous sleeve 32, and calandria tube 202 connecting them.

Second, the lower iron water shield 3 and the calandria tank 200, which are features of the present invention, will be explained based on FIGS. 6 to 11.

First, the lower iron water shield 3 will be explained based on FIGS. 6 and 7-11.

The T-section iron water shield 3 has a structure in which the inner shell 33 is divided into a core region and an annular portion 39, and the inner shell 33 is extended to near the lower end of the reactor support shield wall 400. Inside the inner fuselage, there is a shielding plate (1) 34 and a calandria tank 2.
Multiple lips (1) radially to support 00 35
has been established. On the other hand, the annular portion 39 supporting the circular body is the inner body 33. A box structure is formed by connecting the outer body 36 and the tube plate 38 with a lip (2) 37. Further, a shielding plate (2) 40 is provided within the annular portion.

By adopting the above structure, it is possible to shorten the pressure pipe lower extension pipe by an amount corresponding to the thickness of the reactor support shielding wall 400 (m) as shown in FIG. Not only can the reactor core position be reduced by 3 m, but the reactor core position can be lowered by 2 m.

This further leads to improved earthquake resistance and improved economic efficiency.

Next, the calandria tank will be explained based on FIGS. 8 to 11. 200 calandria tanks are deformed cylindrical containers made of stainless steel with a convex portion on the body 207. The calandria tube 200 connected to the calandria tank upper tube plate 203 and lower tube plate 204 is made of a zirconium alloy, whereas the calandria tank body 207 is made of stainless steel. Therefore, during reactor operation, a difference in thermal expansion due to the difference in materials occurs between the calandria tube 202 and the calandria tank body 207, which places an excessive load on the calandria tube roll joint (see Figure 4). It is necessary to create a structure that avoids this. In the prior art, since the heavy water dump space 201 is provided on the outer periphery of the calandria tank, the distance from the core region where the calandria pipe 202 is attached to the calandria tank body 207 is reduced as shown in FIG. Since (yz, m) was set to be sufficient, a sufficient diaphragm spring effect could be expected in the upper and lower tube plates 203 and 204 of the calandria tank.

In contrast, in the present invention, as shown in FIG. 11, a rapid poison injection system 600 for injecting poison 602 from a control rod guide tube 601 is provided as a function to replace the heavy water dump, and the heavy water dump space is eliminated. The diameters of the upper tube plate 203 and lower tube plate 204 of the doria tank are set to the minimum required size.

Therefore, it was decided to create a diaphragm spring effect as shown in FIG. 9 by making a part of the tank body 207 convex outward by Y1 m.

Here, the length of the convex portion of the tank body can be made thinner than in the case where the upper and lower tube plates of the tank have a diaphragm spring effect in the prior art, so the diaphragm spring effect can be expected to be large, and the diameter can be made smaller.

With the above structure, the heavy water dump space can be eliminated as shown in FIG. 11, so the diameters of the reactor body and containment vessel can be reduced by 2 (Y2 Yl) m. This leads to further improvement in economic efficiency.

Further, as shown in FIG. 12, a partition plate 604 is provided inside the convex portion of the calandria tank. The inside of the convex portion is filled with helium gas 603. The helium gas 603 is injected through a helium injection tube 600. Although the helium injection tube 600 is joined by welding at the convex portion,
The upper iron water shield body has a Perot structure 602. During furnace operation, helium gas 603 is
It is sealed with pulp 601.

This allows the amount of heavy water to be reduced by the volume of helicum gas within the convex portion, which has the effect of reducing equipment costs.

According to the present invention, (1) The length of the lower pressure pipe extension tube can be shortened by an amount corresponding to the thickness of the reactor support shielding wall, which allows for the miniaturization of the fuel exchange machine and the reduction of the core position and the height of the containment vessel. can. Thereby, it is possible to provide a pressure tube type nuclear reactor main body structure with improved earthquake resistance and economical efficiency.

(2) Since the heavy water dump space can be eliminated, the diameters of the reactor body and containment vessel can be reduced. This makes it possible to provide a pressure tube type nuclear reactor main body structure with improved economic efficiency.

(3) Heavy water in the convex portion of the calandria tank can be reduced, which has the effect of reducing equipment costs.

[Brief explanation of the drawing]

FIG. 1 shows the structure of a conventional pressure tube reactor main body. Second
The figure shows the structure of the pressure tube reactor body according to the present invention. FIG. 3 is a structural explanatory diagram of a conventional calandria and an iron water shield according to the present invention. FIG. 4 is a detailed view of section A in FIG. 3. FIG. 5 is an explanatory diagram of the load transmission paths of the conventional and the present invention. FIG. 6 is a structural diagram of a lower iron water shield according to the present invention. FIG. 7 is a sectional view taken along line BB in FIG. 6. FIG. 8 is an explanatory diagram of the diaphragm spring effect of a conventional nuclear reactor body. FIG. 9 is an explanatory diagram of the diaphragm spring effect of the reactor body according to the present invention. FIG. 10 is an explanatory diagram of the rapid poison injection system. FIG. 11 is an explanatory diagram of the effects of the present invention. FIG. 12 is a structural diagram of the convex heavy water reduction method according to the present invention. DESCRIPTION OF SYMBOLS 1... Dobe iron water shielding body, 2... Side iron water shielding body, 3... Lower iron water shielding body, 11... Upper iron water shielding body upper tube plate, 12... Upper part Iron water sleeve, 31...
Lower iron water shielding body lower tube plate, 32... Lower iron water sleeve, 33... Inner body, 34... Shielding plate (1), 35
... Lip (1), 36 ... Outer body, 37 ... Rib (2), 38 ... Tube plate, 39 ... Annular part, 40 ...
・Shielding plate (2), 200... calandria tank,
201... Heavy water dump space, 202 Calandria pipe, 203... Calandria tank upper tube plate, 204.
... Calandria tank lower tube plate, 205 ... Inner ring for rolled joint, 206 ... Reducer (heavy water),
207... Calandria tank body, 300... Pressure pipe assembly, 301... Inlet pipe, 302... Outlet pipe, 303... Support, 304... Pressure pipe lower extension pipe, 400... ... Reactor support shielding wall, 500 ... Fuel exchange machine, 600 ... Helium gas injection pipe, 601 ...
... Valve, 602... Bellow, 603... Heli Fig. 1 5, 2 Fig. 2 452- Off Fig. 20-04-

Claims (1)

[Claims] 1. In a calandria tank convex structure in which the core region of the lower iron water shield body of the vertical downward fuel exchange type pressure tube reactor body is located below the reactor body support concrete surface, the convex part A calandria tank heavy water reduction partition plate that is characterized by having a partition plate on the inside and filling it with helium gas.