Suspension device for high temperature ionization chamber in reactor

Abstract

The present invention relates to a suspension device for a high temperature ionization chamber in a reactor, comprising a suspension device shell that can be inserted into a vertical hole of a reactor shielding platform, a probe support section is arranged at the bottom end of the suspension device shell, a probe is placed in the probe support section, the probe is connected to one end of an armored cable, the other end of the armored cable is led out from a cable outlet at the upper part of the suspension device shell, a flange for supporting is arranged on the suspension device shell, the flange is supported on the top of the reactor shielding platform at the upper end of the hole, and a lifting lug is arranged at the top of the suspension device shell. The present invention specially designs the high temperature ionization chamber suspension device according to the special environment and detection requirements in which the suspension device is used in the reactor, so that it is suitable for the high temperature and strong radiation environment in the reactor, can provide support and shielding for the probe, provide support for the shielding protection structure, and provide an insulating channel for the cable.

Description

Technical Field

[0001] The invention relates to the design of a detector inside a reactor, and in particular to a suspension device for a high-temperature ionization chamber inside the reactor. Background Art

[0002] Reactor neutron detectors are important safety equipment in nuclear power plants. In the operation of the reactor, timely and accurate measurement of the neutron flux rate is required to adjust the insertion depth of the control rods and the concentration of the moderator, so as to achieve the purpose of controlling the reactor power and safe operation. The main reactor detectors are divided into two categories: one is the in-core neutron detector that operates inside the core in a harsh environment and measures the core neutron flux rate distribution, hot spot factors and calibration instrument lights; the other is the in-core neutron detector that operates outside the core in a relatively mild environment and mainly performs total power measurement and early warning. In order to increase the burnup depth and reduce the generation of spent waste, the new generation of reactors adopts a more severe in-core environment, which puts higher requirements on the detectors.

[0003] In-pile detectors are divided into three categories according to different principles: pneumatic activation balls or activation wires using the neutron activation method; fission chambers using the fission method; self-energetic detectors using the neutron nuclear reaction method. The high-temperature ionization chamber suspension device involved in the present invention is designed for the fission ionization chamber. The basic principle of the fission ionization chamber is basically the same as that of the ionization chamber. The fission ionization chamber uses the neutron fission method: neutrons undergo fission reactions with fissile nuclides to produce fission fragments, which then ionize with the gas medium, and the ionized ions are collected by the collecting electrode to generate signals.

[0004] The core neutron injection rate is an important core parameter of the reactor, and the neutron detector is an indispensable safety equipment for the reactor. Due to the harsh environment of high temperature and strong radiation inside the reactor, it is very technically difficult to develop in-core neutron detectors. Summary of the invention

[0005] The purpose of the present invention is to provide a suspension device designed for a high temperature ionization chamber detector in a pile, which provides support and shielding for the probe, supports the shielding protection structure, and provides an insulating channel for the cable in a complex environment in the pile.

[0006] The technical solution of the present invention is as follows: a suspension device for an in-core high-temperature ionization chamber, comprising a suspension device shell that can be inserted into a vertical channel of a reactor shielding platform, a probe support section is arranged at the bottom end of the suspension device shell, a probe is placed in the probe support section, the probe is connected to one end of an armored cable, and the other end of the armored cable is led out from a cable outlet at the upper part of the suspension device shell, a flange for supporting is arranged on the suspension device shell, the flange is supported on the top of the reactor shielding platform at the upper end of the channel, and a lifting ear is arranged at the top of the suspension device shell.

[0007] Furthermore, in the above-mentioned in-pile high-temperature ionization chamber suspension device, the shell of the suspension device is divided into functional segments of different lengths according to different functions, and the functional segments are argon arc welded through connecting blocks.

[0008] Furthermore, in the above-mentioned in-core high temperature ionization chamber suspension device, the shell of the suspension device is a thin-walled tube.

[0009] Furthermore, the thickness of the thin-walled tube ranges from 3 mm to 5 mm.

[0010] Furthermore, in the above-mentioned in-core high temperature ionization chamber suspension device, the outer shell of the suspension device is provided with a variable diameter section, and the outer shell diameter at the lower part of the variable diameter section is smaller than the outer shell diameter at the upper part of the variable diameter section.

[0011] Furthermore, the variable diameter section is located in the middle of the suspension device. After the positions of the shielding function section and the insulation function section are determined according to the neutron injection rate, gamma intensity and temperature parameters in the pile, the variable diameter section is arranged below the insulation function section.

[0012] Furthermore, in the above-mentioned in-core high temperature ionization chamber suspension device, a cable clamp for fixing the armored cable is provided inside the suspension device shell.

[0013] Furthermore, in the above-mentioned in-core high-temperature ionization chamber suspension device, a gasket having a sealing function is provided on the flange portion.

[0014] Furthermore, in the above-mentioned in-core high temperature ionization chamber suspension device, there are two lifting ears, which are symmetrically arranged on both sides of the top end of the suspension device shell.

[0015] The beneficial effects of the present invention are as follows: The present invention specially designs the high-temperature ionization chamber suspension device according to the special environment and detection requirements in which the suspension device is used in the reactor. The external dimensions of the suspension device are designed according to the specific dimensions of the hole (cylindrical) and the detection environment. The length under the flange of the suspension device is determined according to the position from the reactor shielding platform to the core plane. The present invention divides the suspension device into functional sections of different lengths in consideration of installation, stress distribution and other issues, and each section is welded into an integral pipe by argon arc welding; in consideration of controlling the weight of the suspension device itself, a variable diameter treatment is designed below the functional area of ​​the suspension device. The present invention is suitable for high-temperature, strong radiation environments within reactors, and can provide support and shielding for probes, support for shielding protection structures, and an insulating channel for cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the suspension device of the high temperature ionization chamber in the pile of the present invention. DETAILED DESCRIPTION

[0017] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0018] The in-pile high-temperature ionization chamber suspension device provided by the present invention is designed for the research and development of high-temperature ionization chamber detectors, providing support and shielding for the probe in the complex environment of the pile, providing support for the shielding protection structure, and providing an insulation channel for the cable. Since the in-pile high-temperature ionization chamber suspension device is in a harsh environment of high temperature and strong radiation, the stress change of the suspension device, the welding strength and its own weight are all technical issues that need to be considered in this design.

[0019] In order to accurately measure the neutron injection rate during reactor operation, a high-temperature ionization chamber detection device is placed in the vertical channel of the reactor shielding platform. According to the special environment and detection requirements of the high-temperature ionization chamber suspension device in the reactor, the high-temperature ionization chamber suspension device is specially designed. The outer dimensions of the suspension device are designed according to the specific dimensions of the channel (cylindrical) and the detection environment. For example, the diameter of the suspension device needs to be smaller than the diameter of the channel, and the length under the flange of the suspension device is determined according to the position from the reactor shielding platform to the core plane; the design of the suspension device ear takes into account the weight and welding strength of the entire device, and needs Stress calculation and load-bearing calculation were performed; since the suspension device is a thin-walled tube, the interior is divided into different areas according to different functions (shielding area, insulation area, detection area, cable transition area, etc.), so the suspension device is divided into functional sections of different lengths in consideration of installation and stress distribution, and each section is welded by argon arc through the connecting block; in consideration of controlling the weight of the suspension device itself, a diameter reduction treatment is designed below the functional area of ​​the suspension device (the diameter of the thin-walled tube after the functional area becomes smaller); the armored cable passes through the probe directly to the upper part of the flange, and a cable clip is designed at the interface of each section of the armored cable, which serves to reinforce the armored cable. With the above considerations, the high-temperature ionization chamber suspension device was finally designed.

[0020] The specific composition of the high temperature ionization chamber suspension device of the present invention is shown in Figure 1 , mainly including the following parts: 1. Lifting lug, 2. Cable outlet, 3. Suspension device housing, 4. Flange, 5. Gasket, 6. Armored cable, 7. Reducer, 8. Cable clip, 9. Probe support section. Since the suspension device works in a relatively harsh in-pile environment, its design needs to consider many factors. Among them, the key design needs to consider the mechanical strength of the suspension device under special environment, involving the selection of materials, welding methods, pipe wall thickness, weight control of the entire suspension device, etc., strictly preventing the occurrence of problems such as parts falling off and pipe cracking falling into the channel during the lifting and working process.

[0021] like Figure 1As shown, the lifting lug 1 is located at the uppermost end of the suspension device, with one on each side. It is a key component when lifting the entire equipment into the channel inside the pile, and bears the weight of the entire high-temperature ionization chamber; the cable outlet 2 is the outlet of the cable after the cable passes vertically upward from the probe at the bottom end of the suspension device through the entire device, and the rear end is connected to the secondary instrument; the suspension device shell 3 is a supporting component for the high-temperature ionization chamber probe, shielding area, cable, etc., and is a thin-walled pipe. In the special environment inside the pile, it is necessary to consider the change of material stress. In order to reduce the weight of the entire suspension device and ensure the welding strength between the transition sections, the thickness of the thin-walled pipe should not be too thin or too thick, so the optional thickness range is 3mm-5mm; the flange 4 is an important supporting component after the suspension device is placed in the channel, and the main supporting part is at the top of the shielding platform at the upper end of the ionization chamber channel, which can support the weight of the entire equipment; the gasket 5 is on the flange part, and its main function is to ensure The part below the barrier flange is relatively sealed; the armored cable 6 is an important part of the probe signal transmission, the lower end of which is connected to the probe output and the upper end is connected to the ordinary cable; the cable clamp 8 serves to fix the cable; the probe is placed on the probe support section 9 at the lower end of the suspension device to ensure that the center of the probe is flush with the core midplane; considering the convenience of installation of the suspension device probe, cable, etc. and the stress changes in high temperature and strong radiation environment, the high-temperature ionization chamber suspension device is designed with a multi-section welding mode, and the welding method is argon arc welding; in order to further reduce the weight of the suspension device, a variable diameter section 7 is also designed, that is, the diameter of the pipes in the upper sections of the suspension device is consistent with the channel size, and the diameter of the pipes in the lower sections is smaller. The variable diameter section is arranged below the insulation functional area, approximately in the middle of the suspension device, and the final position is determined based on the position of the functional area (shielding area, insulation area) determined by parameters such as the neutron injection rate, gamma intensity, and temperature in the reactor.

[0022] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A suspension device for a high temperature ionization chamber in a pile, characterized in that: The invention comprises a suspension device shell (3) which can be inserted into a vertical hole of a reactor shielding platform, a probe support section (9) is arranged at the bottom end of the suspension device shell (3), a probe is placed in the probe support section (9), the probe is connected to one end of an armored cable (6), and the other end of the armored cable (6) is led out from a cable outlet (2) at the upper part of the suspension device shell (3), a flange (4) having a supporting function is arranged on the suspension device shell (3), the flange (4) is supported on the top of the reactor shielding platform at the upper end of the hole, and the probe is placed in the probe support section (9), and the probe is connected to one end of an armored cable (6). The other end of the armored cable (6) is led out from a cable outlet (2) at the upper part of the suspension device shell (3), and a flange (4) having a supporting function is arranged on the suspension device shell (3). The flange (4) is supported on the top of the reactor shielding platform at the upper end of the hole. ) is provided with a lifting ear (1) at the top, the shell (3) of the suspension device is divided into functional sections of different lengths according to different functions, and the functional sections are argon arc welded through connecting blocks. The shell (3) of the suspension device is provided with a variable diameter section (7), the shell diameter of the lower part of the variable diameter section is smaller than the shell diameter of the upper part of the variable diameter section, and the variable diameter section (7) is located in the middle of the suspension device. After the positions of the shielding functional section and the heat preservation functional section are determined according to the neutron injection rate, gamma intensity and temperature parameters in the pile, the variable diameter section (7) is arranged below the heat preservation functional section.

2. The in-pile high temperature ionization chamber suspension device according to claim 1, characterized in that: The suspension device housing (3) is a thin-walled tube.

3. The in-pile high temperature ionization chamber suspension device according to claim 2, characterized in that: The thickness of thin-walled tubes ranges from 3mm to 5mm.

4. The in-pile high temperature ionization chamber suspension device according to claim 1, characterized in that: A cable clamp (8) for fixing the armored cable (6) is arranged inside the suspension device housing (3).

5. The in-pile high temperature ionization chamber suspension device according to claim 1, characterized in that: A gasket (5) having a sealing function is arranged on the flange part.

6. The in-pile high temperature ionization chamber suspension device according to claim 1, characterized in that: There are two lifting ears (1), which are symmetrically arranged on both sides of the top end of the suspension device shell (6).

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