JPS5992398A - Fast breeder - 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 the Invention] The present invention is a method for continuously monitoring field lightning at the pressure boundary of reactor internals in a loop-type fast breeder reactor that uses liquid metal as a coolant. This invention relates to a fast breeder reactor equipped with an in-service inspection mechanism.

[Technical downside of the invention and its problems] Nuclear power generation 771! Inspection during the service life of a nuclear reactor! This is done for the purpose of constantly providing assurance that the installation is safe in order to prevent public disasters, and is based on the electrical engineering code JEAC-4205 and the "pressure pressure" established by the American Society of Mechanical Engineers (ASME). 11 of “Standards for Containers and Piping”
Chapter (hereinafter referred to as ASMECODE 5ECTION
(referred to as I). These standards were established mainly for the pressure vessels and piping of nuclear facilities, that is, the pressure boundary areas. As long as the integrity of these pressure boundaries is maintained, public safety will not be compromised. Perhaps for this reason, it is not always clear what kind of inspection should be carried out and for what purpose, due to the difficulty of the inspection method for inspecting the in-core equipment during its service life.

This situation also applies to C in fast breeder reactors.

In other words, although domestic regulations for in-service inspections of fast breeder reactors have not yet been established, the ASM, which was enacted in 1981,
F C0DE 5FCrlONxt 1) EVI
SION III (high-speed short story) Teha, fast reactor is low 1”
Since l = 'C-, even if it were to break, less energy would be released, and the filtration material is also made of a highly tough material, so we hypothesized that there would definitely be a leak before a major accident occurs. Inspections during the service life of the cooling l boundary have been developed with a focus on visual leakage monitoring, and for the internal structure of the reactor, it is still unclear which equipment and how much abnormality should be detected. There is ambiguity.

Figure 1 shows an overview of a fast breeder reactor. 4 is removed (=J is removed. The core 1 is immersed in the coolant 5,
A cover gas 6 is filled above it.

The core 1 and the core tank 7 that accommodates it are connected to a core support plate 8 i
It is attached to the inner edge of the core support structure mount 10 whose outer edge is fixed to the inner wall of the reactor vessel 2 via J5 and the core support plate support 9. A lower Blenheim container 11 is fixed below the core support plate 8, and an inlet pipe 12 opens into the container 11.

The coolant introduced into the lower plenum vessel 11 through the artificial piping 12 is rectified there, and then introduced into the reactor core 1 via the high pressure blenum 13 and a module (not shown). After the coolant heated by the core 1 rises and reaches the upper lunum 14, it is led to an intermediate heat exchanger (not shown) through the outlet pipe 15, where it is cooled by transferring heat to the secondary coolant. , and returns to the lower Blenheim vessel 11 via the inlet pipe 12. 16 indicates the lower outer blenheim.

In the above-mentioned ASMF C0DE, it is clear that the reactor vessel 2 must be inspected during its service life along the cooling l boundary. Visual inspection is specified.C
However, it is unclear what and how to test.

In particular, the lower Blenheim vessel 11 constitutes the pressure boundary of the cold Nl material, and if this B-force boundary were to break, it would lead to a cold 7i111Δ loss accident, etc., so inspections during its service life are extremely important. There's urine in there.

However, in-service inspections for force boundaries such as the lower Blenheim vessel 11 are very difficult to carry out because, even though they are indirect visual inspections, they are inspected for defects or leaks in liquid metal coolant. .

As mentioned above, there is another protection system outside the pressure boundary of the reactor internals as a coolant boundary, so if the pressure boundary were to fail, C would also be less severe than the failure of the cold NIII boundary. Although the risk of causing a disaster to the public is considered to be slight, considering the operational efficiency and reliability of nuclear facilities,
If a leak occurs at the pressure boundary, it is necessary to accurately detect it.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and is equipped with an in-service inspection function that can accurately detect leakage at the pressure boundary of the reactor internal structure. The purpose is to provide fast breeder reactors.

[Summary of the invention] In order to achieve the above-mentioned object, the fast breeder reactor of the present invention divides the inside of the reactor vessel into an upper blennium and an outer lower blennium.
A through hole for measuring leakage coolant is provided in a part of the structure, and a leak detector is provided near the hole.

[Embodiments of the Invention] The present invention will be described in detail below with reference to FIGS. 2 and 3. Note that in these drawings C, the same components as those in FIG. 1 are designated by the same reference numerals.

The core tank 7 containing the reactor core 1 and the core support plate 8 are liquid-tightly attached to the core support plate support 9 by the holes 1-17.
The core support plate support 9 is
8 to the inner edge of the core support structure mount 10 in a liquid-tight manner.

The inlet pipe 12 passes through the core support structure mount 10, and its tip opens into the lower plenum vessel 11. Upper plenum 1 divided into “C” by core support structure mounting base
4 and the lower outer blemish 16 are not built with a solid structure, but a cutting board 19 is installed at the core support structure mount 10 at the penetration part of the inlet pipe 12 to prevent coolant from flowing out. The cold eye A is made to pass through the penetration part and to make it difficult for C to flow out.

A through hole 20 is provided in the core support structure mounting base 10 as shown in FIG.
C is fixed to the C liquid livestock through the C.

A leak detector 24 is installed directly above the orifice 21 to detect the flow of coolant flowing through the A-refrigerant 21 . This leak detector 24 is attached to the lower end of a holding tube 25 depending from the shielding plug.

In the fast breeder reactor of the present invention configured as described above, 1
The coolant inside the lower outer blennium 16 is the Dobe blennium 14.
The coolant present therebetween acts as a heat shield and is at approximately the same temperature as the inlet temperature of the coolant flowing into the lower Blenheim vessel 11.

During normal operation, the coolant flows into the high-pressure blenum 13 via the inlet piping 12 and the lower plenum vessel 11, is regulated by the Mogicor 26, flows into each C core constraint element 27, is heated (flows into the upper plenum 14) , and then transferred to the intermediate heat exchanger via the outlet piping. Therefore, as long as there is no abnormality in the pressure boundary of the coolant in the reactor, during normal operation, fuel exchange, and maintenance, the movement of the coolant C between the lower outer blennium 16 and the upper brenum 14 will be limited due to the temperature difference caused by the start-up and stoppage. Only a small amount comes in and out due to relationships, and it's almost non-existent. However, when a cold iJ1 leak occurs in a part of the lower Blenheim container 11, the coolant begins to flow out to the upper Blenheim 14 side from the through hole 20 for measuring the cold Nj material leakage flow rate. This escaping coolant is sensed by leak detector 24 . Therefore, the output of the leakage detector 24 allows continuous monitoring of abnormalities in the lower plenum vessel 11 forming the pressure boundary.

Note that the above-mentioned installation position of the leakage coolant measurement through-hole 20 does not necessarily have to be the core support structure mounting base 10, and may be located at a similar location.

[Effect of the invention 1 The above-mentioned fast breeder reactor of the present invention is capable of inspecting the pressure boundary of the cooling fJI material on the inside of the reactor internal structure during the service period by checking the leakage coolant installed on the lateral J green material mount in the reactor. A leak monitoring device consisting of a jΔ hole leak detector for measurement and a J-C
This can be done by continuous monitoring (゛Giru no C1)
It will be possible to detect and prevent serious accidents that may cause public disasters, and a highly reliable nuclear reactor will be obtained. In addition, the in-service inspection according to the present invention can be performed in a shorter period of time than conventional methods, and is reliable as a system for continuously monitoring and detecting abnormalities at the coolant pressure boundary in reactor internal structures. The device is easy to maintain or replace, and has high reliability.

[Brief explanation of the drawing]

Figure 1 is a schematic cross-sectional view of a fast breeder reactor, Figure 2 is a vertical cross-sectional view of the main parts showing an embodiment of the present invention, and Figure 3 is an enlarged view of the leakage detection device in Figure 2. There is a sectional view C. 1・・・・・・・・・・・・Reactor core 2・・・・・・・・・Reactor vessel 3・・・・・・
・・・・・・Shielding plug 4・・・・・・・・・・・・Core upper mechanism 5・・・・・・・・・Cold W material 6・・・・・・ζ・・...Cover gas 7...Core tank 8...Core support plate 9...
... Core support plate support 10 ......
...Core support structure mounting base 11...
・・Lower plenum container 12 ・・・Artificial piping 13 ・・・High pressure blenum 14
・・・・・・・・・Upper Blenheim 15・・・・・・
・・・・・・Outlet piping 16・・・・・・・・・・・・
Lower outer blemish 17.18...Mounting bolt 19...Cold material outflow baffle plate 20
.........Through hole 21... Orifice 22...
......Partition plate 23...Partition tube 24...Leak detector 25...
......Holding tube 26...Module 27...
...... Patent attorney representing core components Su
Yamasa - Figure 1 Figure 4 Figure 3

Claims (1)

[Claims] <1) In a loop-type fast breeder reactor that uses liquid metal as a cold FDL material (2) leakage into a part of the structure that divides the inside of the reactor vessel into an upper blemish and an outer lower blemish. A fast breeder reactor characterized by having a number of through holes for measuring coolant and a leak detector installed near the holes. (2) A structure that divides and covers the upper blenum and the outer lower blennium is attached to the core support structure. The fast breeder reactor according to claim 1, wherein the fast breeder reactor is a stand.