KR20120121280A - The crack and flaw detection device for high pressure and high temperature vessel - Google Patents

Abstract

PURPOSE: A device for detecting defects of a pressure container is provided to photograph variations on a surface of a pressure container caused by a heating body in the inside of the pressure container as thermal images and displays the same, thereby precisely inspecting the pressure container after cooling a surface of a pressure container in order to have a uniform temperature distribution. CONSTITUTION: A device for detecting defects of a pressure container comprises a pressure container(100), a cooling unit, a photographing unit(300), a display unit(400), and a controlling unit(500). A heating body having thermal energy is embedded or moved in the inside of an accommodation unit of the pressure container. The pressure container is heated by the thermal energy of the heating body. The cooling unit jets a cooling gas on a surface of the pressure container, thereby cooling the surface of the pressure container. The photographing unit photographs variations on the surface temperature of the pressure container as thermal images. The displaying unit the thermal images photographed by the photographing unit. The controlling unit controls the operation of the cooling unit and photographing unit.

Description

The crack and flaw detection device for high pressure and high temperature vessel}

The present invention relates to a device for detecting a defect in a pressure vessel, and more particularly, a pressure vessel heated to a high temperature and subjected to a pressure, in particular, a vessel in which a surface of a reactor vessel for power generation is cooled using a cooling gas and reheated by heat generated therein. The present invention relates to a defect detection apparatus for a pressure vessel capable of diagnosing the safety of the vessel by photographing a surface temperature change of the vessel by thermal imaging to detect cracks or defects in the pressure vessel.

Conventional reactors have a reactor vessel for containing nuclear fuel, and the reactor vessel is designed by welding several castings, such as a cylinder body, a nozzle, a flange, and the like. The reactor vessel is coupled to a primary coolant circuit that circulates the primary coolant over the fuel in the reactor vessel and to a generator that extracts energy imparted to the primary coolant by the raw materials.

The reactor vessel may rupture rapidly if the primary cooling system provided for transferring heat from the core of the reactor to the generator fails, for example due to a decrease in primary coolant pressure due to leakage or rupture of the connection line.

In contrast, the reaction rate of the fuel may not be controlled, and the reactor vessel itself may be cracked or melted by heat generated during the reaction of the nuclear fuel, causing the reactor vessel to rupture from the inside, and the radiation may leak out to the outside in large quantities.

For the reasons described above, the reactor vessel itself must be guaranteed in the structural safety of the reactor vessel while it is embedded in the thick concrete containment vessel of the power plant, and from time to time to ensure the structural safety of such reactor vessel, the reactor vessel and the couplings installed inside the reactor vessel Checking

Reactor vessels are inspected prior to installation in the reactor and, when in operation, from time to time to check for defects. In-service inspection is usually performed underwater with remote control operation while maintaining the placement and movement of the inspection tool with very high precision.

To date, this work has been done using huge fixed robot manipulators used by many nuclear industries. In other words, the sensor is mounted at the end of the manipulator and moved to determine whether the reactor vessel is defective from the sensor signal obtained at this time.

 On the other hand, a method of inspecting whether or not a defect is generated may be applied by using a temperature at which a defect is generated and a temperature at a normal part is different. Since the nuclear reactor is exposed to heat for a long time, the surface temperature of the reactor vessel, i.e., the temperature of the defective part and the normal part is the same or almost the same, making it difficult to distinguish between the defective part and the normal part. have.

The present invention has been made to solve the above problems, and an object thereof is to provide a pressure vessel defect detection apparatus capable of accurately detecting a defect of a reactor vessel during operation.

Defect detection device of the pressure vessel according to the present invention for achieving the above object is a pressure vessel that is provided with a receiving space so that the heat source having a thermal energy is built or moved, and is heated by the heat energy of the heat source, the heat A cooling unit for cooling the surface of the pressure vessel by injecting a cooling gas to the surface of the pressure vessel heated by the element, and a surface of the pressure vessel gradually heated by the heat source after being cooled by the cooling unit. And a photographing unit which photographs the temperature change as a thermal image, a display unit which displays the thermal image photographed by the photographing unit, and a controller which controls driving of the cooling unit and controls operation of the photographing unit.

The pressure vessel is provided with an inlet through which the heat source is introduced into the receiving space from the outside and an outlet through which the heat source is discharged from the receiving space to the outside, and heats the heat source to supply the receiving space. A circulation unit connected to a circulation unit for recovering the heat source from the accommodation space, the circulation unit having a storage space for recovering the heat source discharged from the accommodation space, a heater for heating the heat source in the circulation tank, and the circulation unit; And a circulation pump for transferring the heat source in the tank to the receiving space, wherein the cooling unit has a gas tank filled with the cooling gas and a gas transfer pipe through which the cooling gas discharged from the gas tank is transferred and the gas transfer pipe. Coupled and the other end is directed toward the surface of the pressure vessel. Is installed on the gas injection nozzle and the gaseuyi songgwan for injecting each gas is controlled by the control unit and a valve for opening and closing the gaseuyi songgwan.

The cooling unit may uniformly spray the gas tank filled with the cooling gas, the gas transfer pipe through which the cooling gas discharged from the gas tank is transferred, and the cooling gas transferred from the gas transfer tube to the surface of the pressure vessel. It is formed so as to surround the surface of the pressure vessel and is provided with an injection port coupled to the gas transfer pipe therein is formed a flow path to move the cooling gas injected into the injection hole and faces the surface of the pressure vessel A gas injection cover having a plurality of gas ejection holes formed on one side thereof in communication with the flow path, and a valve installed at the gas transport pipe to open and close the gas transport pipe under control of the controller, wherein the gas ejection hole is formed from the inlet. As the distance increases, the inner diameter gradually increases.

According to the defect detection apparatus of the pressure vessel according to the present invention, after cooling the surface of the pressure vessel to have a uniform temperature distribution, the surface temperature change of the pressure vessel by the internal heat source is photographed and displayed by a thermal image of the pressure vessel. It allows for close inspection.

1 is a schematic view showing a first embodiment of a pressure vessel detection apparatus according to the present invention,
Figure 2 is a schematic diagram showing a second embodiment of the pressure vessel detection apparatus according to the present invention,
3 is an exploded perspective view showing a gas injection pad in the cooling unit of the pressure vessel according to the present invention shown in FIG.

Hereinafter, a defect detection apparatus of a pressure vessel according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 shows a first embodiment of a defect detection apparatus of a pressure vessel according to the present invention.

Referring to the drawings, the defect detection apparatus 1 of the pressure vessel includes a pressure vessel 100, a cooling unit 200, a photographing unit 300, a display unit 400, and a control unit 500.

The pressure vessel 100 has a cylindrical body 110 provided with a receiving space 101 so that the upper and lower openings and the heat source 150 having thermal energy therein may be embedded therein, and the upper and lower portions of the body 110. The receiving space 101 includes an upper flange 120 and a lower flange 130 bonded to the upper and lower ends of the body 110 to be hermetically sealed. The pressure vessel 100 is formed of a metal material that is heated by receiving heat energy of the heat source 150. The pressure vessel 100 in the present embodiment is a reactor vessel in which nuclear fuel is embedded in a nuclear power plant.

The accommodating space 101 of the pressure vessel 100 has a heat source 150 (hereinafter, referred to as “nuclear fuel”) capable of generating thermal energy by causing nuclear fission in a chain.

The pressure vessel 100 transfers heat from the nuclear fuel 150 via the surroundings of the nuclear fuel 150 to make steam using thermal energy generated by nuclear fission of the nuclear fuel 150 and to drive the turbine using the steam. The injection port 102 through which the received water is supplied and the discharge port 103 through which steam generated by the thermal energy of the nuclear fuel 150 are discharged are formed.

Although not shown in the drawing, a neutron reflector is disposed outside the nuclear fuel 150 to prevent neutron leakage, and the outermost side prevents leakage of gamma rays and neutron rays, which are strong radiations generated in the pressure vessel 100. For the shield is installed. In addition, the pressure vessel 100 is a power generation facility including a turbine for generating power using steam discharged to the discharge port 103, a condenser for condensing the steam after driving the turbine, and pressurized to supply the condensed water from the condenser to the inlet The circulation system including the pump is connected.

The cooling unit 200 is to cool the surface of the pressure vessel 100 by injecting a cooling gas to the surface of the pressure vessel 100 heated by the thermal energy of the nuclear fuel 150, the gas tank 210 and the gas transfer pipe 220, a gas injection nozzle 230, and a valve 240 are provided.

The gas tank 210 is filled with liquefied gas that is liquefied by cooling or compressing gas to cool the surface of the heated pressure vessel 100. Preferably, the gas filled in the gas tank 210 uses nitrogen as the gas for cooling.

The gas tank 210 is provided with a gas transfer pipe 220 through which the cooling gas is transferred, and the gas transfer pipe 220 is connected to the gas injection nozzle 230 by a controller which will be described later to block or supply the cooling gas to the gas injection nozzle 230. The valve 240 for opening and closing the 220 is provided.

The gas injection nozzles 230 are installed at a predetermined interval on the outside of the gas tank 210 so that the cooling gas supplied from the gas tank 210 is evenly sprayed on the surface of the pressure vessel 100.

The photographing unit 300 photographs the surface temperature change of the pressure vessel 100 gradually heated by the heat source 150 after being cooled by the cooling unit 200 in a thermal image, and in the pressure vessel 100. An infrared camera is applied to detect the emitted infrared rays.

The display unit 400 displays a thermal image of the pressure vessel 100 photographed by the photographing unit 300 and is connected to the photographing unit 300 and a control unit to be described later.

The controller 500 controls the operations of the cooling unit 200 and the photographing unit 300 to control the opening and closing of the valve 240 and the photographing cycle of the infrared camera, and to display the thermal image photographed by the photographing unit 300. To be displayed through 400.

When the diagnosis mode for detecting the defect of the pressure vessel 100 is started, the controller 500 cools the surface of the pressure vessel 100 by injecting a cooling gas through the cooling unit 200.

The pressure vessel 100 cooled by the cooling gas is again heated by the nuclear fuel 150 that emits heat through the continuous nuclear reaction, and the imaging unit 300 is discharged from the pressure vessel 100. The thermal image of the pressure vessel 100 is obtained by sensing the wavelength of the infrared region.

When one portion of the pressure vessel 100 is formed to be thinner than another portion or has cracks or melts formed on the inner wall due to high pressure and high temperature, after the instant cooling through the cooling unit 200, the inside of the pressure vessel 100 may be cooled. When the temperature rises again due to heat, the defective portion of the pressure vessel 100 appears to have a higher temperature because the temperature rises faster than the normal portion where the defect does not occur.

That is, the defective portion having a thickness thinner than the normal portion where the defect does not occur is that the temperature is easily increased by the heat inside the pressure vessel 100. The photographing unit 300 obtains the difference in temperature distribution on the surface of the pressure vessel 100 as a thermal image, and allows the user to confirm that a defect occurs in a portion where the temperature distribution is different through the display unit 400.

Reference numeral 170 is an isolation container for preventing the radiation of the radiation in the pressure vessel to the outside.

Figure 2 shows a second embodiment of the defect detection apparatus of the pressure vessel of the present invention.

The defect detection device 2 of the pressure vessel according to the present invention shown in FIG. 2 is for inspecting the pressure vessel 100a before being installed in the reactor and determining whether the pressure vessel 100a can be applied to the reactor vessel. 100a), a circulation unit 600 providing the heat source 150a to the pressure vessel 100a, a cooling unit 200 for cooling the pressure vessel 100a, and a photographing unit for photographing a thermal image of the pressure vessel 100a. 300, a display unit 400 for displaying a thermal image, and a control unit 500 for controlling the driving of the cooling unit 200 and the photographing unit 300.

Here, the cooling unit 200, the imaging unit 300, the display unit 400 and the control unit 500 are described in detail in the detailed description of the first embodiment of the pressure vessel defect detection apparatus according to the present invention described above. Duplicate explanation is omitted since it is the same.

The pressure vessel 100a discharges the heat source 105a from the accommodation space 101a to the outside via the inlet 102a and the accommodation space 101a through which the heat source 150a flows into the accommodation space 101a from the outside. A discharge port 103a is provided, and is connected to a circulation part 600 that heats the heat source 150a to supply it to the accommodation space 101a and to recover the heat source 150a from the accommodation space 101a.

The circulation unit 600 includes a circulation tank 610 in which a storage space for recovering the heat source 150a discharged from the accommodation space 101a is provided, and a heater 620 for heating the heat source 150a in the circulation tank 610. And a circulation pump 630 for transferring the heat source 150a in the circulation tank 610 to the accommodation space.

Reference numeral 170a is a housing or case in which the pressure vessel may be installed to be isolated from the external space so as to remove an element that may affect the temperature change of the pressure vessel from the outside.

The defect detection device 2 of the pressure vessel described in this embodiment provides a condition similar or identical to the temperature and pressure conditions inside the reactor operating in the pressure vessel 100a.

Looking at the process of detecting the defect of the pressure vessel (100a), first, by supplying a heated heat source to the pressure vessel (100a) to make the internal state of the pressure vessel (100a) similar to the temperature and pressure conditions inside the reactor vessel in operation state or Make it the same condition. When the temperature and pressure inside the pressure vessel 100a are similar to or the same as the conditions inside the reactor vessel, the controller 500 injects a cooling gas through the cooling unit 200 to instantaneously touch the surface of the pressure vessel 100a. Cool.

The pressure vessel 100a cooled by the cooling gas is continuously raised in temperature by the heat source continuously supplied from the circulation unit 600, and the photographing unit 300 is moved from the pressure vessel 100a. The thermal image of the pressure vessel is obtained by sensing the wavelength of the emitted infrared region. Through the above process, it is possible to detect whether the pressure vessel 100a is defective.

3 illustrates another embodiment of the cooling unit 200 included in the apparatus for detecting a defect of a pressure vessel according to the present invention, unlike FIG. 2.

Referring to the drawings, the cooling unit includes a gas tank, a gas transfer pipe, a gas injection cover and a valve, and the cooling unit uses the gas injection nozzle 230 described above with reference to FIG. 2 to maintain a uniform temperature on the surface of the pressure vessel 100a. The remaining configuration except for the gas injection cover 250 in the structure changed to the gas injection cover 250 so as to cool by the same as the configuration in the first embodiment described above.

Gas injection cover 250 is formed in a shape surrounding the outer side of the pressure vessel (100a), the injection port 251 is provided to receive the cooling gas transferred to the gas transfer pipe 220, the injection hole 251 therein A flow path 252 through which the cooling gas introduced through the movement is formed.

The flow path 252 may be formed in a lattice shape on the gas injection cover 250 or may have a hollow structure as shown in the drawing.

Dozens of gas ejection holes 253 communicating with the flow path 252 are formed at one side of the gas injection cover 250 facing the surface of the pressure vessel 100a, but gradually increase as the distance from the inlet 251 increases. It is formed.

The structure of the gas ejection hole 253 is the cooling gas injected through the gas ejection hole 253 located at a close distance to the injection hole 251 and the gas ejection hole 253 located at a long distance from the injection hole 251. By varying the amount of the pressure vessel 100a to prevent the surface of the pressure vessel 100a from being unevenly cooled, the same amount of cooling gas may be ejected regardless of the distance from the inlet 251, so that the pressure vessel 100a may be cooled. ) Have the same temperature distribution.

The pressure vessel defect detection apparatus according to the present invention described above has been described with reference to one embodiment shown in the drawings, but this is merely exemplary and various modifications and equivalents from those skilled in the art will be appreciated. It will be appreciated that other embodiments are possible.

Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100, 100a: pressure vessel 200: cooling unit
210: gas tank 230: gas injection nozzle
250: gas injection cover 300: photographing unit
400: display unit 500: control unit
600: circulation part 610: circulation tank
620: heater 630: circulation pump

Claims (3)

A pressure vessel provided with a receiving space so that a heat source having heat energy can be embedded or moved and heated by the heat energy of the heat source;
A cooling unit for cooling the surface of the pressure vessel by injecting a cooling gas to the surface of the pressure vessel heated by the heat source;
A photographing unit which photographs the surface temperature change of the pressure vessel gradually heated by the heat source after being cooled by the cooling unit as a thermal image;
A display unit which displays a thermal image photographed by the photographing unit;
And a control unit controlling the driving of the cooling unit and controlling the operation of the photographing unit. The method of claim 1,
The pressure vessel is provided with an inlet through which the heat source is introduced into the receiving space from the outside and an outlet through which the heat source is discharged from the receiving space to the outside, and heats the heat source to supply the receiving space. Is connected to the circulation unit for recovering the heat source from the receiving space,
The circulation unit includes a circulation tank provided with a storage space for recovering the heat source discharged from the accommodation space, a heater for heating the heat source in the circulation tank, and a circulation pump for transferring the heat source in the circulation tank to the accommodation space. ,
The cooling unit has one end coupled to the gas tank filled with the cooling gas and the gas transfer pipe to which the cooling gas discharged from the gas tank and the gas transfer pipe are coupled, and the other end of which sprays the cooling gas toward the surface of the pressure vessel. And a gas injection nozzle and a valve installed at the gas transfer pipe and controlled by the control unit to open and close the gas transfer pipe. The method of claim 1,
The cooling unit may uniformly spray the gas tank filled with the cooling gas, the gas transfer pipe through which the cooling gas discharged from the gas tank is transferred, and the cooling gas transferred from the gas transfer tube to the surface of the pressure vessel. It is formed so as to surround the surface of the pressure vessel and is provided with an injection port coupled to the gas transfer pipe therein is formed a flow path to move the cooling gas injected into the injection hole and faces the surface of the pressure vessel A gas injection cover having a plurality of gas ejection holes formed on one side thereof in communication with the flow path, and a valve installed at the gas transfer pipe to open and close the gas transfer pipe under control of the controller;
The gas ejection hole is pressure vessel defect detection device, characterized in that the inner diameter is gradually increased as the distance from the injection port.

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