JPS5995500A - Bwr 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] [Technical Field of the Invention] The present invention relates to a γjij IH, (I) water swelling reactor (hereinafter referred to as B
WR).

[Technical background of the invention] In general c BWR, the bottom of the reactor pressure vessel
It has a configuration in which multiple instrumentation tubes and a control crusher fuse (hereinafter referred to as CHD housing) are connected to the CHD housing, which detects the core output and increases safety. I am driving while using M. Forty to eighty instrumentation tubes and CHD housings are provided depending on the size of the reactor. Cooling water is also accommodated within the reactor pressure vessel.

This cooling water consists of water supplied from the water supply port connected to the side wall of the reactor pressure vessel, and water supplied from the recirculation system.
The water supplied from the water supply port is purified water and has not been activated. The water supplied from the recirculation system is water that has passed through the reactor core, and the water is fed in after floating crud and the like have been removed by the fresh water trap of the recirculation system.

[Problems with background technology]

Generally, cooling water is supplied from the side wall of the reactor Tagata vessel located above the reactor core, flows down the outside of a shroud provided on the inner periphery of the reactor pressure vessel, flows below the reactor core, circulates above the reactor core, and rises. The cooling water also contains fission products, projectile rust (hereinafter referred to as cladding), and the like. Then, the crud floating in the cooling water 71 with a high flow rate is removed by the fresh water trap of the re-shielding ring system, but the crud floating in the cooling water with a low flow rate settles at the bottom of the reactor pressure vessel and the instrumentation pipe and It may be deposited in the gaps of the CHD housing.This may cause problems such as radiation exposure for workers during maintenance inspection work below the reactor pressure generator, for example.

[Purpose of the invention]

The purpose of the present invention is to reduce the radiation exposure of workers during maintenance and inspection work by removing crud deposited in the gaps between the lower part of the reactor pressure vessel, the instrumentation tube, and the CRD housing, thereby increasing safety. The object of the present invention is to provide a boiling 1tα water reactor that can greatly improve the energy efficiency.

[Summary of the invention]

The boiling water reactor according to the present invention includes a reactor pressure vessel that houses a reactor core therein, an instrumentation tube that is connected to the lower part of the reactor pressure vessel and houses a neutron detector assembly, and an instrumentation tube that houses a neutron detector assembly.
The reactor is equipped with a crud removal mechanism provided between the lower part and the reactor pressure vessel.

In other words, the crud removal mechanism removes the lower part of the reactor pressure vessel.
This structure removes crud that has accumulated in the gaps between instrumentation pipes.

Therefore, when performing maintenance and inspection work on the lower part of the reactor pressure volume 4i, instrumentation pipes, etc., it is possible to reduce the exposure of workers to radiation, and to greatly improve safety.

[Embodiments of the invention]

Embodiments of the present invention will be explained with reference to the drawings. In the drawings, reference numeral 1 indicates a reactor pressure vessel. Inside this reactor 1 pressure vessel 1, there are a plurality of controls S (not shown) and Fuel fruit union (ri1)
(not shown), etc., is accommodated therein. A shract 3 is provided between the reactor core 2 and the reactor pressure vessel 1. What is the above reactor pressure content? A recirculation system 4 is provided outside S1. This recirculation (IM LM system or the inlet nozzle 5 and outlet nozzle 6 formed in the reactor pressure vessel 1, the recirculation system piping 7 disposed between these two nozzles 5 and 6, and the recirculation It is composed of a live water trap (not shown) inserted into the system piping 7 and a recirculation pump 8.The recirculation system 4 is configured to forcefully circulate cooling water. is provided with a return/defeat instrumentation tube (hereinafter referred to as in-core flange) 9, which accommodates a neutron detector east combination (hereinafter referred to as A-A core monitor) 10.The lower end of the in-core housing 9 is provided with a A flange portion 9A is formed and connected to the in-core flange 11 by bolts (not shown) or the like.

A cladding removal 41A IAl 3 is provided between the joint 12 between the in-core flange 11 and the flange portion 9A and the reactor pressure vessel 1. This crud removal mechanism 13 includes a piping system 15 disposed between the joint 12 and a nozzle 14 provided on the side wall of the reactor pressure vessel 1 in the upper direction d of the Incoano Kujifugu 9;
It consists of a fresh water trap 16 inserted from the joint 12 side, and a circulation pump 17. Then, by moving the circulation pump 17, the cooling water is circulated, and the crud deposited in the bottom of the reactor pressure vessel 1 and the Incoano Ujifugu 9 is flowed out. It is.

According to the above configuration, the cooling water flows through the reactor core 2 from the bottom to the top as shown by the arrow in the figure, and the temperature rises to 14≦. And the unillustrated air and moisture? ill: '; and flows out of the reactor pressure vessel 1 through a steam dryer, receiver, etc., and is sent to the turbine via the main steam pipe. And the floating crud is like 1 above! When extracting ring system 4, it is removed by a fresh water trap.

On the other hand, the crud that has settled in the lower part of the reactor Senriki vessel 1 and the Incore/Kujifugu 9 is fluidized by the cooling 7J (circulated by 1 drive of the 1st pump 17, and 4n
'K The crud removal mechanism is removed by the trap 16, that is, the crud removal mechanism is provided between the joint 12 between the in-core flange 11 and the lower flange portion 9A of the in-core housing 9 and the reactor pressure vessel 1. The crud deposited in the lower part of the pressure content 4 and in the Incoano Ujifugu 9 can be removed. Therefore, for example, it is possible to reduce radiation exposure of workers during maintenance and inspection work, thereby improving work efficiency and greatly improving safety.

In the above embodiment, a crud removal mechanism was provided between the incoano housing 9 and the reactor pressure vessel 1, but the present invention is not limited to this, and may be applied to a CRD housing. Also, multiple in-core housings 9 or CR
One cladding removal mechanism 13 may be provided for each DI.

Furthermore, the circulation operation does not have to be continuous and may be intermittent.

〔Effect of the invention〕

A water expansion reactor according to the present invention includes a reactor pressure vessel that houses a reactor core therein, an instrumentation tube that is connected to the lower part of the reactor pressure vessel and that accommodates a neutron detection four-band combination. This is a special feature that includes a crud removal mechanism provided between this instrumentation sound chamber and the reactor pressure vessel.

That is, the crud removal 6''A FA removes the crud deposited in the gap between the instrumentation pipes at the bottom of the reactor pressure vessel.

Therefore, maintenance of the lower part of the reactor pressure vessel and instrumentation pipes, etc. 2
The dog has the advantage of being able to reduce the burden on workers during inspection work, greatly improving safety, and so on.

[Brief explanation of the drawing]

The figure is a sectional view showing one embodiment of the present invention. 1...1 Reactor pressure vessel, 2...Reactor core, 8...In-core housing (instrumentation tube), 9...In-core monitor (neutron detection: 4 aggregates), 12...Joint part, 13.
...Crud removal iB +ti.

Claims (1)

[Scope of Claims] fl) A reactor pressure vessel housing a reactor core therein, an instrumentation tube in contact with the lower part of this reactor pressure vessel; a damaged instrumentation tube housing a neutron detector assembly; A boiling aha water nuclear reactor comprising: a crud removal mechanism provided between the reactor pressure vessel and the reactor pressure vessel. (2) The crud removal mechanism includes a piping system installed in the curve between the lower flange of the instrumentation pipe and the side wall of the reactor pressure vessel, and a piping system extending from the lower flange of the instrumentation pipe to this piping system. A boiling water nuclear reactor according to claim 1, characterized in that it is comprised of a water trap and a circulation pump.