CN108320817B - Air pressure sealing method - Google Patents
Air pressure sealing method Download PDFInfo
- Publication number
- CN108320817B CN108320817B CN201711457304.0A CN201711457304A CN108320817B CN 108320817 B CN108320817 B CN 108320817B CN 201711457304 A CN201711457304 A CN 201711457304A CN 108320817 B CN108320817 B CN 108320817B
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- Prior art keywords
- heating furnace
- pressure
- furnace
- fuel element
- heating
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Classifications
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/02—Fuel elements
- G21C3/04—Constructional details
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Shaping Metal By Deep-Drawing, Or The Like (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
Abstract
The invention relates to the field of fuel assembly manufacturing, and particularly discloses a gas pressure sealing method, which comprises the following steps: step 1, additionally installing a flow guide tool; step 2, loading the heating furnace material boat into the heating furnace; step 3, adding a fuel element to be tightly pressed; step 4, inflating the heating furnace; and 5, releasing high-pressure gas. The method of the invention causes the pressure difference between the inside and the outside of the fuel element through the pressure change caused by the instant rush of the high-pressure gas into the heating furnace, can finish the close fit of the cladding tube, the fuel core body and the end plug under the condition of ensuring the surface of the product to be undamaged by means of the change of the material performance, ensures that the product has good straightness and stable and reliable quality.
Description
Technical Field
The invention belongs to the field of fuel assembly manufacturing, and particularly relates to a pneumatic sealing method.
Background
According to literature research, the related technology related to the air pressure sealing of the pool type reactor fuel assembly is not applied to the production of the same type of products in China, and belongs to the first research and use. The prior art related to the present invention, which can achieve the same technical result, is a mechanical spinning technology, that is, welded fuel elements are clamped on a lathe, and a cladding tube is tightly pressed on a core body and an end plug by using a roller in a mechanical rolling way. Although the process can meet the production requirement, the process has the following defects:
1) cannot be formed at one time: the mechanical spinning process can not be formed at one time, the rolling reduction must be adjusted for many times and aluminum scraps and burrs are cleaned to reach the specified size of the groove, and the working efficiency is low;
2) local non-uniformity of straightness: the welded element has good straightness, but after mechanical spinning, local stress unevenness is caused when the roller passes through the outer surface of the element for multiple times, and the straightness is not uniform any more when the roller becomes poor;
3) damage to the weld: the fuel elements of the pool reactor are welded at two ends in a hole plugging welding mode, and the distance between the fuel elements and a point needing spinning is very close. In the rotating process of the element, the welding seam is torn due to the repeated contact and pressing of the roller, internal defects occur if the welding seam is light, and external cracks directly occur if the welding seam is heavy;
4) potential impact on core quality: the fuel core used by the pool type reactor fuel assembly is a dispersive fuel core, is obtained by extrusion, is not sintered, and has low strength. The rolling surface of the roller for multiple times can possibly cause extrusion damage to the fuel core body, and microcracks occur;
5) poor surface quality: the roller passes the surface for multiple times and is pressed down on the groove part, so that inevitable indentation and surface damage are caused, the surface quality is influenced, and the difficulty is increased for subsequent renovation.
After the fuel element of the pool type reactor is pulled and sealed, the core body and the outer wrapping shell are well attached, but after the fuel element is welded and filled with helium, the attachment degree between the wrapping shell and the end plug and between the wrapping shell and the core body is reduced, so that the attachment degree needs to be improved again by adopting a proper process.
Disclosure of Invention
The invention aims to provide a pneumatic sealing method which meets the requirement of completing the tight sealing between a core and a cladding and between an end plug and the cladding of a fuel element of a pool reactor under the condition of no damage.
The technical scheme of the invention is as follows:
a gas pressure sealing method is suitable for pressing and tightly adhering a core body of a dispersion fuel element and a cladding tube and an end plug and the cladding tube of a pool reactor, and comprises the following steps:
step 1, a flow guiding tool is arranged at a high-pressure gas inlet end on a material boat of a heating furnace, and the high-pressure gas is guided, so that the gas with lower temperature is uniformly distributed around a fuel element;
step 2, loading the heating furnace material boat into the heating furnace, closing the furnace door of the heating furnace and starting heating;
step 3, when the temperature of the heating furnace reaches 380-400 ℃, opening the furnace door of the heating furnace, putting a fuel element to be subjected to air pressure sealing, closing the furnace door of the heating furnace, continuing heating, and preserving heat after the temperature of the heating furnace reaches 380-400 ℃ again;
step 4, after heat preservation is carried out for 1 hour, an inflation valve of the heating furnace is opened to enable the air pressure in the heating furnace to reach 18-22 MPa, the air pressure is kept for 5-7 min, and then heating is stopped;
and 5, opening a vent valve of the heating furnace, releasing high-pressure gas, opening the heating furnace after the pressure in the heating furnace is reduced to the atmospheric pressure, and taking out the fuel element.
The flow guide tool in the step 1 is an aluminum pipe, the inner diameter of the aluminum pipe is 1-2 times larger than the outer diameter of the fuel element, and when the fuel element is placed in the heating furnace, the other end of the flow guide tool is connected with one end of the fuel element.
The heating furnace is a tubular heatable high-pressure container.
In the step 3, the furnace temperature of the heating furnace is the same before and after the furnace door of the heating furnace is opened and closed.
In the step 3, the furnace temperature of the heating furnace is 390 ℃ before and after the furnace door of the heating furnace is opened and closed.
In step 4, the air pressure in the heating furnace reaches 20MPa, and the air pressure is kept for 7 min.
The invention has the following remarkable effects:
the method of the invention causes the pressure difference between the inside and the outside of the fuel element through the pressure change caused by the instant rush of the high-pressure gas into the heating furnace, can finish the close fit of the cladding tube, the fuel core body and the end plug under the condition of ensuring the surface of the product to be undamaged by means of the change of the material performance, ensures that the product has good straightness and stable and reliable quality.
Drawings
FIG. 1 is a flow chart of a gas pressure sealing method.
Detailed Description
The invention is described in further detail below with reference to the figures and the embodiments.
A gas pressure sealing method is suitable for pressing and tightly adhering a core body of a dispersion fuel element and a cladding tube and an end plug and the cladding tube of a pool reactor, and comprises the following steps:
step 1, a guide tool is arranged at a high-pressure gas inlet end on a material boat of a heating furnace, and the guide tool guides the filled high-pressure gas, so that the gas with lower temperature can be uniformly distributed around a fuel element, and the large difference between the front and back adhesion degrees of the fuel element and a cladding tube is avoided, thereby ensuring the same indentation quality at two ends of the fuel element; the flow guide tool is an aluminum pipe, the inner diameter of the aluminum pipe is 1-2 times larger than the outer diameter of the fuel element, and when the fuel element is placed in the heating furnace, the other end of the flow guide tool is connected with one end of the fuel element;
step 2, loading the heating furnace material boat into the heating furnace, closing the furnace door of the heating furnace and starting heating;
step 3, when the temperature of the heating furnace reaches 380-400 ℃, opening the furnace door of the heating furnace, putting a fuel element to be subjected to air pressure sealing, closing the furnace door of the heating furnace, continuing heating, and preserving heat after the temperature of the heating furnace reaches 380-400 ℃ again;
step 4, after heat preservation is carried out for 1 hour, an inflation valve of the heating furnace is opened to enable the air pressure in the heating furnace to reach 18-22 MPa, the air pressure is kept for 5-7 min, and then heating is stopped;
and 5, opening a vent valve of the heating furnace, releasing high-pressure gas, opening the heating furnace after the pressure in the heating furnace is reduced to the atmospheric pressure, and taking out the fuel element.
The heating furnace is a tubular heatable high-pressure container, and can bear gas pressure of more than 24MPa and temperature of more than 450 ℃.
Examples
Step 1, a guide tool is arranged at a high-pressure gas inlet end on a material boat of a heating furnace, and the guide tool guides the filled high-pressure gas, so that the gas with lower temperature can be uniformly distributed around a fuel element, and the large difference between the front and back of the adhesion degree of a core body of the fuel element and a cladding tube and the adhesion degree of an end plug and the cladding tube are avoided, thereby ensuring the same indentation quality at two ends of the fuel element; the flow guide tool is an aluminum pipe, the inner diameter of the aluminum pipe is 1-2 times larger than the outer diameter of the fuel element, and when the fuel element is placed in the heating furnace, the other end of the flow guide tool is connected with one end of the fuel element;
step 2, loading the heating furnace material boat into the heating furnace, closing the furnace door of the heating furnace and starting heating;
step 3, when the temperature of the heating furnace reaches 390 ℃, opening the furnace door of the heating furnace, placing a fuel element to be subjected to air pressure sealing, closing the furnace door of the heating furnace for continuous heating, and preserving heat after the temperature of the heating furnace reaches 390 ℃ again;
step 4, after heat preservation is carried out for 1 hour, an inflation valve of the heating furnace is opened to enable the air pressure in the heating furnace to reach 20MPa, the air pressure is kept for 7min, and then heating is stopped;
and 5, opening a vent valve of the heating furnace, releasing high-pressure gas, opening the heating furnace after the pressure in the heating furnace is reduced to the atmospheric pressure, and taking out the fuel element.
Claims (6)
1. A gas pressure sealing method is suitable for pressing and tightly adhering a core body of a dispersion fuel element and a cladding tube as well as an end plug and the cladding tube of a pool reactor, and is characterized in that: the method comprises the following steps:
step 1, a flow guiding tool is arranged at a high-pressure gas inlet end on a material boat of a heating furnace, and the high-pressure gas is guided, so that the gas with lower temperature is uniformly distributed around a fuel element;
step 2, loading the heating furnace material boat into the heating furnace, closing the furnace door of the heating furnace and starting heating;
step 3, when the temperature of the heating furnace reaches 380-400 ℃, opening the furnace door of the heating furnace, putting a fuel element to be subjected to air pressure sealing, closing the furnace door of the heating furnace, continuing heating, and preserving heat after the temperature of the heating furnace reaches 380-400 ℃ again;
step 4, after heat preservation is carried out for 1 hour, an inflation valve of the heating furnace is opened to enable the air pressure in the heating furnace to reach 18-22 MPa, the air pressure is kept for 5-7 min, and then heating is stopped;
and 5, opening a vent valve of the heating furnace, releasing high-pressure gas, opening the heating furnace after the pressure in the heating furnace is reduced to the atmospheric pressure, and taking out the fuel element.
2. A gas pressure bonding method according to claim 1, wherein: the flow guide tool in the step 1 is an aluminum pipe, the inner diameter of the aluminum pipe is 1-2 times larger than the outer diameter of the fuel element, and when the fuel element is placed in the heating furnace, the other end of the flow guide tool is connected with one end of the fuel element.
3. A gas pressure bonding method according to claim 2, wherein: the heating furnace is a tubular heatable high-pressure container.
4. A gas pressure bonding method according to claim 3, wherein: in the step 3, the furnace temperature of the heating furnace is the same before and after the furnace door of the heating furnace is opened and closed.
5. A gas pressure sealing method according to claim 4, wherein: in the step 3, the furnace temperature of the heating furnace is 390 ℃ before and after the furnace door of the heating furnace is opened and closed.
6. A gas pressure bonding method according to claim 5, wherein: in step 4, the air pressure in the heating furnace reaches 20MPa, and the air pressure is kept for 7 min.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711457304.0A CN108320817B (en) | 2017-12-28 | 2017-12-28 | Air pressure sealing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711457304.0A CN108320817B (en) | 2017-12-28 | 2017-12-28 | Air pressure sealing method |
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| Publication Number | Publication Date |
|---|---|
| CN108320817A CN108320817A (en) | 2018-07-24 |
| CN108320817B true CN108320817B (en) | 2019-12-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711457304.0A Active CN108320817B (en) | 2017-12-28 | 2017-12-28 | Air pressure sealing method |
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| Country | Link |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53115498A (en) * | 1977-03-18 | 1978-10-07 | Toshiba Corp | Nuclear fuel element |
| DE3727529A1 (en) * | 1987-08-18 | 1989-03-02 | Kernforschungsanlage Juelich | Swimming-pool nuclear reactor |
| JP5677184B2 (en) * | 2011-04-28 | 2015-02-25 | 株式会社東芝 | Fuel cladding tube assembly and manufacturing method thereof |
| CN107112054A (en) * | 2014-12-29 | 2017-08-29 | 泰拉能源公司 | nuclear material processing |
| CN107293341A (en) * | 2016-04-12 | 2017-10-24 | 国家电投集团科学技术研究院有限公司 | Pool reactor |
-
2017
- 2017-12-28 CN CN201711457304.0A patent/CN108320817B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53115498A (en) * | 1977-03-18 | 1978-10-07 | Toshiba Corp | Nuclear fuel element |
| DE3727529A1 (en) * | 1987-08-18 | 1989-03-02 | Kernforschungsanlage Juelich | Swimming-pool nuclear reactor |
| JP5677184B2 (en) * | 2011-04-28 | 2015-02-25 | 株式会社東芝 | Fuel cladding tube assembly and manufacturing method thereof |
| CN107112054A (en) * | 2014-12-29 | 2017-08-29 | 泰拉能源公司 | nuclear material processing |
| CN107293341A (en) * | 2016-04-12 | 2017-10-24 | 国家电投集团科学技术研究院有限公司 | Pool reactor |
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| Publication number | Publication date |
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| CN108320817A (en) | 2018-07-24 |
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