JPS58225386A - Lmfbr type reactor - 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 a fast breeder reactor that uses liquid metal (sodium) as a coolant.

A conventional liquid metal cooled breeder reactor, as shown in Figure 1,
The furnace vessel (1), whose upper seven flange parts are placed and supported on the pedestal (2) on the side of the shielding concrete structure (not shown) that covers the entire furnace, is [
The liquid metal (sodium) for cooling, which is supported and accommodated and introduced into the lower part of the furnace vessel (1) from the inlet pipe (5), is connected to the relatively low-temperature liquid metal layer (a) and above it. A high temperature liquid metal layer (b) that cools the core structure (4) and reaches a temperature of 400 to 450C is formed, and the exit piping (
The cover gas layer (→ is placed on the pedestal (2) and fitted into the upper opening of the furnace vessel (1). [Shielding bladder (structure that is shielded by force).

However, in the above-mentioned liquid metal cooled fast breeder reactor, the temperature inside the reactor changes greatly during reactor operation, shutdown (trip), etc., and the reactor vessel expands and contracts accordingly, causing vibration.
Vibration prevention measures are an important issue.In order to reduce the vibration of the reactor internal structure, the reactor core structure is slidably mounted and supported on the inward 7 flange, but the core structure is Since objects are fused onto the inward 7 flange and its sliding properties are impaired, making it impossible to obtain its integrity and reliability, a hardening treatment such as hardfacing welding with Stellite is applied to the upper surface of the inward flange to prevent the aforementioned self-fusion. Prevents wear and improves sliding properties. However, when performing hardening treatment directly on the upper surface of the inward 7 flange as described above, the hardening treatment is performed on a large-scale member, requiring a wide range of area, and the heat treatment equipment required for the treatment and the cooling rate are limited. Due to restrictions such as these, it is actually difficult to apply the hardening treatment uniformly over the entire upper surface of the wide inward 7-lunge, and there are drawbacks such as cracks occurring after construction.

The present invention was developed to solve the above-mentioned difficulties in conventional liquid metal cooled fast breeder reactors. In a liquid metal cooled fast breeder reactor in which a cover gas layer on the liquid metal surface in the reactor vessel is shielded by a shielding plug disposed on the upper opening side of the reactor vessel, an arc-shaped member having at least a number of a number of surfaces hardened. A hardening ring formed into a ring shape by overlapping the inclined end faces of the furnace vessel is disposed on an inwardly directed 72-inch ring provided on the inner surface side of the reactor vessel, and the reactor core structure is supported through the hardening ring. The objective is to develop a liquid metal cooled fast breeder reactor in which the sliding support performance of the reactor internals relative to the inward flanges is maintained to ensure the integrity and reliability of the reactor internals. It is in the point of providing.

The present invention has the above-mentioned configuration, and provides an inward flange in which a hardened ring formed into a ring shape by overlapping the inclined end faces of a plurality of arc-shaped members whose surfaces have been hardened at least is provided on the inner circumferential side of a furnace vessel. Since the core structure is supported through the hardening ring, it is easy to harden the arc-shaped member formed in a small area, and the entire hardening ring is hardened. In addition to being able to homogenize the processing,
By overlapping the inclined end faces of the arc-shaped members, the hardening ring responds to changes in the furnace temperature with the inward flange.
i The hardening ring can be easily thermally expanded and contracted to minimize the leakage of liquid metal, and the hardening treatment on the surface of the hardening ring is made homogeneous so that it will not be damaged and will not fuse with the reactor core structure. The sliding support performance of the structure can be significantly improved, the sealing performance can be ensured, and the integrity, functionality, and reliability of the reactor internal structure can be greatly improved.

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

An embodiment of the present invention is shown in FIG. 2 (5) (c) to FIG. Annular inward direction 7 fixed on the inner peripheral surface side
The inward 7-lunge (4) is a core structure that is slidably mounted and supported on the upper surface side of the inward 7-lunge (3). 7 Ring-shaped hardening rings (11) (12
) is arranged, and the lower surface periphery (41) of the core structure (4) is placed on the upper surface side of the hardening rings (11) and (12) and is slidably supported, forming a sliding support structure. .

In addition, the hardening rings (11) and (12) are shown in FIG.
As shown in B), a plurality of arc-shaped members (11s, (12')
It is formed into a ring shape by the combination of the arc members (1
1. (As shown in Fig. 3, 1 cup has a hardened layer (11□) (12□) applied to its entire outer circumferential surface by means such as hardfacing welding using Stellite, etc. , as shown in FIG. 2(B), both ends are provided with inclined end surfaces (11□) (12□) that are opposite in plan view, and adjacent inclined end surfaces (11□λ (11□), the same inclined end surfaces (12□),
(12□) Ring-shaped hardening rings (
11), (12), and each hardening ring (1
1) and (12) are arranged so as to overlap inward and outward in a plan view, and the inclination directions of the inclined end surfaces (112) and (122) of the hardening rings (11) and (12) are opposite, and their overlapping parts (11□, 11□), (1
2□, 12□) are at different positions as shown in the figure.

Furthermore, each of the inclined end faces (11□) and (12□) of each of the hardening rings (11) and (12) is provided with the
However, as shown in ), a plurality of enlarged grooves (15
) (15 ridges are arranged vertically in plan view, and the inner enlarged grooves (15) (15 ridges have inclined end faces (11 □) (12 □) overlapped with each other as shown in Fig. 4 (c)). There are appropriate intervals between the two.

In addition, (16) in the figure indicates an arc-shaped member (11) (12') forming the hard rings (11) (12).
3) A fastening bolt that fastens to the upper surface side, and has several sections as appropriate.

The illustrated embodiment has the structure described above,
The hardening rings (11), (12) have a plurality of arc-shaped members (1
1 (consisting of 12 combinations, each arc-shaped member (
Since hardening can be applied to 11 (12') surfaces, overlay welding and cooling treatment, etc. on the relatively small surface area can be uniform, resulting in a homogeneous hardened layer (111 x 12').
, ) is obtained, and a homogeneous hardening layer is formed on the entire surface of the hardening ring (11 x 12).
The core structure (4), the hardening rings aυ, (12), and the inward flan (3) all undergo different thermal expansions and contractions, but at that time, the hardening rings (11) and (12) The inclined end faces (11) at both ends of the member (11
2) (11 □ in (12 □) (12 □) superimposed structure facilitates thermal expansion and contraction, and also allows for radial expansion and contraction. The hardened layer (111) can easily follow expansion and contraction.
(121) is less likely to be damaged.

In addition, when the temperature inside the furnace changes, the inward flan:
(See Figure 1) A pressure difference is created between the hardening rings 0υ (1
Liquid metal (sodium) is about to leak in part 2), but there is a low-temperature liquid metal layer (a) on the side! Each arc-shaped member (11) is
12 are pressed, and the overlapping portions of the inclined end surfaces of each hardening ring (11x12) (11□, 11□), (12□, 1
2□) tends to be narrowed by 1, and the leakage of liquid metal at the overlapping portion is kept to a minimum trace amount.

Furthermore, the leakage is caused by the inner and outer hardening rings (11) and (1).
3, loose overlapping parts (11□, 11□) and (12□,
By differentiating the positions of the grooves (12°) and (12°) as shown in Figure 2, it is possible to further reduce the amount of leakage. By reducing the size, the amount can be kept even smaller, ensuring sealing performance in the hardening rings (11) and (12), and effectively transferring the liquid metal in the low-temperature liquid metal layer (a) to the core structure ( 4)
It can be introduced to the side without reducing the cooling effect.

Accordingly, according to the embodiment, the hardening ring (II) (
The hardening treatment of the surface in step 12) makes it homogeneous so that it is hard to be damaged and there is almost no fusion with the reactor core structure (4), which significantly improves the sliding support performance of the reactor internal structure (4) and improves the sealing performance. can be ensured, and the health, functionality, and reliability of the reactor internals can be greatly improved.

In the above embodiment, two hardening rings, one on the inside and one on the outside, were applied. However, the number of hardening rings can be increased or decreased as appropriate, and the hardening treatment is not limited to the surface. Various implementations are also possible.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

1 is a vertical cross-sectional view showing the overall structure of a conventional liquid metal cooled fast breeder reactor; FIG. 2A is a vertical cross-sectional view showing the structure and arrangement of a hardening ring according to an embodiment of the present invention; Figure 2) is a plan view of the hardening ring in Figure 2 (G), and Figure 6 is a plan view of the hardening ring in Figure 2 (
5) is an enlarged cross-sectional view of the hardening ring, FIG. 4(5) is an enlarged view of the ■ part of FIG. 2(5), and FIG. 4(B) is an enlarged view of the overlapping portion of the inclined end surfaces. 1: Furnace vessel 2: Pedestal 3: Inward 72 inch 4: Core structure 7: Shielding plug 11.12: Hardening ring 11'
, 12': Arc-shaped member 11□iz1: Hardened layer 11
2.12□ = Inclined end face 15, 15': Enlarged groove 16: Fixing bolt A: Low temperature liquid metal layer B: High temperature liquid metal layer N: Cover gas layer Sub-agent Patent attorney Shige Okamoto Two other people

Claims (1)

[Scope of Claims] A reactor vessel containing a reactor core structure is suspended vertically by a pedestal, and a cover gas layer on the liquid metal level in the reactor vessel is covered by a shielding plug disposed on the upper opening side of the reactor vessel. In a shielded liquid metal cooled fast breeder reactor, the inclined end faces of a plurality of arc-shaped members whose surfaces have been hardened at least are superimposed [a ring-shaped hardening ring is provided on the inner peripheral surface side of the reactor vessel]. A liquid metal cooled fast breeder reactor characterized in that the core structure is supported via the hardening ring by being disposed on a flange.