KR100871599B1 - Reactor internals gap - automatic remote measuring system and method - Google Patents

Abstract

An apparatus and a method for automatically measuring a gap of an internal structure of a reactor are provided to reduce a measurement time by automatically gap between a reactor core support can protrusion and a reactor vessel protrusion remotely by using a digital probe. A plurality of digital probes(14) are formed in an outer side of a plurality of reactor vessel protrusions and reactor core support cans formed in the inner surface of a reactor vessel(1) and measures gap between the reactor vessel protrusions and the reactor core support cans fitted to the reactor vessel protrusions. The computer is connected to the digital probe and stores and indicates the value of the gap measured in the digital probe. A solenoid valve is controlled by the computer, and controls the compressed air which is supplied in order to operate the digital probe through the air hose(16). An air compressor supplies the compressed air to the digital probe. A standard block gauge(12) is inserted into the gap. The digital probe measures the gap after welding the reactor core support can, a reactor core tube, and a lower support structure.

Description

Reactor Internals Gap-Automatic Remote Measuring System And Method

1 is a cross-sectional view of a conventional reactor internal structure.

FIG. 2 is a partial cross sectional view showing a gap between a core support protrusion and a reactor vessel protrusion in a conventional reactor.

3 is a configuration diagram of a gap remote precision measurement apparatus according to the present invention.

4 is a partial cross-sectional view showing a core support protrusion and a reactor vessel protrusion with a digital probe according to the present invention.

5 is a cross-sectional view of the reactor internal structure in which the gap teleprecision device of the present invention is installed.

The present invention relates to an automatic remote precision measurement apparatus for internal structure clearance of a nuclear reactor, and in the installation and installation of a core support cylinder, a core barrel, and a lower support structure in a reactor vessel during the construction of a nuclear power plant, a reactor vessel protrusion and a core support protrusion are provided. The present invention relates to a device for automatically remotely measuring a gap to satisfy an allowable gap requirement therebetween.

1 is a cross-sectional view of a conventional reactor internal structure, in which FIG. 1A shows a cross section of the reactor and FIG. 1B shows a longitudinal section of the reactor.

2 is a partial cross-sectional view showing a gap 9 between the core support protrusion 7 and the reactor vessel protrusion 8 in a conventional reactor.

1A, 1B and 2, in the conventional nuclear power plant construction, the core support barrel 2 installed inside the reactor vessel 1, and the core barrel 3 and the lower support structure 4 are The assembly work begins in a separate state.

Here, the core barrel 3 and the lower support structure 4 are supplied assembled in the factory.

As described above, the reason for the construction site assembly in the state of being separated into two parts is that the measurer measures the reactor vessel (1) in order to measure the gap 9 between the reactor vessel protrusion 8 and the core support protrusion 7. This is because it must go directly to the bottom.

That is, the core support cylinder 2 and the core barrel 3 and the lower support structure 4 are separated so that the measurer can enter the reactor vessel 1 lower.

In order to measure the distance between the core support protrusion 7 and the reactor vessel protrusion 8, that is, the gap 9, the core support cylinder 2 without the core barrel 3 and the lower support structure 4 installed therein ) Is installed in the reactor vessel (1), and then the measurer enters the reactor vessel (1), measures the gap (9), and accurately calculates the dimensions of the filling (not shown) according to the size of the gap (9). Process to fit the dimensions and attach to the reactor vessel protrusion groove (11).

After the filling is installed, the core supporter 2 is again assembled to the reactor vessel 1, and the measurer enters the lower portion of the reactor vessel 1 and the core supporter 2 and measures the gap 9 again. Check that the clearance allowance at final assembly is met.

After confirming that the clearance is within the allowance, weld the contact portions of the core barrel (3) and the lower support structure (4) and the lower flange of the core support cylinder (2) (the welded joint is referred to as the "core holder assembly"). Assembled in the reactor vessel (1).

This assembly method takes several months, such as manual gap measurement work, welding work and non-destructive inspection, increasing the overall construction air of the nuclear power plant, and acts as a factor that increases the cost of power plant construction.

The installation process of the reactor internal structure will be described in more detail with reference to FIGS. 1 and 2 as follows.

As shown in FIG. 1, the reactor includes a reactor vessel 1, a reactor vessel lid (not shown), a control rod driving device (not shown), and the like. As an internal structure of the reactor vessel 1, a fuel assembly (not shown) is shown. And a core barrel (3) surrounding the nuclear fuel assembly and a core support cylinder (2) for supporting the nuclear fuel assembly.

A lower support structure (4) is provided below the core barrel (3) and the fuel assembly to support the weight of the core barrel (3) and the fuel assembly, and the lower support structure (4) rests on the core stationary (5) in the reactor. It is seated.

Heat generated by the fission chain reaction of the fuel assembly is absorbed by the coolant at low temperature entering the inlet nozzle.

The coolant whose temperature rises is transferred to the steam generator through the outlet nozzle to generate steam, which is converted into electrical energy by rotating the turbine.

The core support cylinder 2 is assembled in the form of fit with the core support protrusion 7 and the reactor vessel protrusion 8 of the concave-convex shape located at the bottom.

The fitting interprotrusion assembly serves to restrain the radial or circumferential movement of the core support cylinder assembly.

This is to prevent deformation due to mutual contact even if the reactor and the internal structure expand due to the high temperature generated by the nuclear fission chain reaction, and the final allowable gap 9 is formed between the core support protrusion 7 and the reactor vessel protrusion 8. It is a requirement.

In order to meet these allowable gap 9 requirements, a process of measuring the gap 9 and determining the fill thickness from the measured value is required.

In the construction of a nuclear power plant, the existing method of installing the core support barrel 2, the core barrel 3 and the lower support structure 4 in the reactor vessel 1 is as follows.

First, only the core support cylinder 2 is inserted into the reactor vessel 1, and then the gap 9 between the surface hardened portion 13 surface of the core support protrusion 7 and the surface of the reactor vessel protrusion groove 11 is measured. .

In the method of measuring the gap 9, the measurer first lowers the reactor vessel 1 while only the core support cylinder 2 is inserted into the reactor vessel 1 so that the gap gauge is directly inserted into the core support protrusion 7. Insert into a sphere to measure the gap 9 between the reactor vessel protrusions 8.

The gap 9 measurement should be made for a total of 72 points, since 12 points are measured for each of the six projections at sixty circumferential intervals of the reactor vessel 1.

Therefore, the conventional gap 9 measurement time, dimensional calculation time and fabrication time of the gap usually take several weeks.

Based on the size of the measured gap (9) in consideration of the requirements of the gap (9) allowed after the final assembly, the size of the padding is calculated, the padding is processed and manufactured in accordance with the calculated standard and mounted on the reactor vessel protrusion (8). .

The measurement reference point of the gap 9 is the surface of the surface hardened portion 13 formed on the inner side surface of the core support cylinder 2.

Mount the core to the reactor vessel protrusion (8) and then reinsert the core support (2) into the reactor vessel (1) to ensure that the final clearance (9) is within the tolerance requirements. (1) Go back to the bottom and use filler gauge to check the gap satisfaction.

After confirming that the final gap 9 satisfies the requirements, the core support barrel 2 is lifted out of the reactor vessel 1 and the core support cylinder 2 and the core barrel 3 and the lower support structure 4 are removed. Weld to form a body.

This welding work is carried out outside the reactor vessel 1 and usually takes several weeks.

As such, the core support cylinder 2, and the core barrel 3 and the lower support structure 4 are combined to form a one-body structure is called a core support cylinder assembly.

The core support cylinder combination, in which the two parts are integrated, is assembled in the reactor vessel 1, and subsequent assembly of the inner structure of the reactor vessel 1 proceeds.

In the conventional reactor installation method as described above, the core support cylinder (2), and the core barrel (3) and in order to provide a measuring space in which the measurer can measure the gap 9 directly at the bottom of the reactor vessel (1); The process of welding the two parts into one body is only possible after the lower support structure 4 cannot be integrally manufactured in advance and is separated into two parts to determine whether the final clearance 9 satisfies the permissible requirements. Going through.

In other words, the welding process for making the core support cylinder assembly must be a subsequent process after the gap specification is determined and the subsequent filling process is established, and thus serves as a critical process of assembling the reactor internal structure.

In addition, the conventional gap 9 measurement process has a problem in that the construction period of the nuclear power plant is increased due to a long measurement period because the measurement device must measure the gap of 72 points by hand in a narrow space.

In addition, the conventional gap 9 measurement process is difficult to objectively verify the measured values because 72 points are measured by one operator in a very narrow space.

Accordingly, an object of the present invention is to shorten the time for measuring the gap by remotely measuring the gap between the core support projection and the reactor vessel projection remotely using a digital probe in the manufacturing and assembling process of the reactor. The present invention provides a gap teleprecision device that enables a core support barrel and a process of welding the core barrel and the lower support structure to fabricate the core support cylinder assembly before the gap measurement process.

In order to achieve the object as described above, the gap teleprecision device according to an embodiment of the present invention, the reactor vessel, the core support barrel, and the reactor including a core barrel and the lower support structure, the reactor vessel A plurality of digital probes for measuring a gap between a plurality of reactor vessel protrusions formed on an inner surface of the core vessel and a plurality of core support protrusions formed on an outer surface of the core support protrusion and fitted with the reactor vessel protrusions; A computer connected to the digital probe and displaying and storing the measured value of the gap measured by the digital probe; And a solenoid valve controlled by the computer, the solenoid valve controlling compressed air supplied to drive the digital probe through an air hose, wherein the digital probe comprises the core support barrel, the core barrel and the lower support structure. After the welding, the gap is measured.

In addition, in order to achieve the object as described above, the gap teleprecision method according to a preferred embodiment of the present invention, (A) a core support cylinder installed inside the reactor vessel and supporting the fuel assembly, the core support Welding and assembling a core barrel disposed inside the barrel and surrounding the nuclear fuel assembly and a lower support structure installed below the core barrel and supporting the weight of the nuclear fuel assembly; And (B) after the welding assembly of step (A) is completed, a plurality of reactor vessel protrusions formed on the inner surface of the reactor vessel and the core support outer surface to prevent flow of the core support cylinder and And measuring the gap between the plurality of core support projections fitted with the projection with a plurality of digital probes.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the gap teleprecision measuring device according to the present invention.

3 is an overall configuration diagram of a gap teleprecision measuring apparatus of the present invention, and FIG. 4 is an assembly diagram of a sensor and a standard block gauge.

As shown in FIG. 3, the gap teleprecision apparatus includes a plurality of distance measuring digital probes 14, a data processing accessory system, an air system for driving the digital probes, and a power supply system.

Four to six digital probes 14 may be inserted into one core support protrusion 7.

In order to reduce the time and cost of calculating the effective calculation of the gap to be measured, it is preferred that at least four digital cavities 14 are inserted in one core support protrusion 7.

Therefore, the digital probes 14 may be configured to be 48 to 72 in total by connecting 16 to 24 units per chamber to the three chambers 36, 37, and 38.

Here, each chamber 36, 37, 38 is a solenoid valve 18, air hose 16, data cable 17, probe interface module 21, RS-485 communication cable 22 for controlling the compressed air , RS-422 communication cable 20 and the air distributor 28 and the like.

Chambers 36, 37, and 38 are connected to computer 27 via RS232-422 converter 19 to control solenoid valve 18, and digital probe 14 measurement data includes USB module 24 and USB hub. It appears on computer 27 through 26.

In addition, the compressed air for driving the digital probe 14 passes from the air compressor 34 to the ordinary air cleaning unit 33, the precision remote pneumatic regulator 31, the air hose 29, and the distributor 30. Supplied to the chambers 36, 37, 38.

The supplied compressed air is discharged after the digital probe 14 is driven, and connects the recirculation hose 29 and the distributor 30 so that the discharged air is recycled.

The remote pneumatic regulator 31 may be connected to the solenoid valve 18 and the signal cable 32 so that the air pressure may be remotely controlled from the computer 27.

In addition, a power cable 35 is connected to the probe interface module 21 to supply power.

The digital probe 14 measuring the gap 9 may use a linear variable differential transducer, and the linear variable differential transducer digital probe 14 measures a distance by contacting an object to be measured.

The linear variable differential transducer digital probe 14 can measure up to micro units.

The digital probe 14 used in the present invention is a diameter that can be inserted into the existing manual measuring tool 10 of the core support protrusion 7, and the reactor vessel in the process of inserting the core support assembly into the reactor vessel 1 also. It is preferable that a short length is used so that interference with (1) does not occur.

To maintain this characteristic, the digital probe 14 is driven by compressed air.

4 is a cross section in which the digital probe 14 is assembled to the core support protrusion 7, and the digital probe 14 is inserted into and fixed to the core support protrusion 7 by the digital probe fixture 15.

The gap 9, which is the distance between the core support protrusion 7 and the reactor vessel protrusion groove 11, is usually several tens of millimeters, but the digital probe 14 usually has a smaller measuring range than this gap 9, so the exact dimensions are Proven tens of millimeters thick standard block gauges 12 are mounted between the reactor vessel protruding grooves 11.

Thus, the gap teleprecision device of FIG. 3 measures the distance from the core support cylinder surface hardening portion 13 to the gap or surface of the gap between the standard block gauges 12.

FIG. 5 is a view showing arrangements of devices in actual measurement using the gap teleprecision device of the present invention. As shown in FIG. 5, three chambers 36, 37, and 38 are disposed below the core support cylinder assembly. The computer 27, the air compressor 34, and the power supply cable 35 are disposed outside the reactor vessel 1.

The digital probes 14 and cables are connected from each chamber 36, 37, 38 to the core support protrusions 7 and from the chambers 36, 37, 38 to the computer 27 and the air compressor 34. And a hose sufficiently connected.

The gap teleprecision measuring device having the above configuration is used to measure the distance between the surface hardened portion 13 and the reactor vessel protrusion groove 11 of the core support cylinder protrusion 7 of FIG. 2.

However, since the distance between the surface hardened portion 13 of the core support projections 7 and the reactor projection grooves 11 usually exceeds the measurement range of the digital probe 14, the reactor vessel projection grooves 11 are not provided in advance. Attach the standard block gauge 12 with the correct thickness to it.

Therefore, the distance actually measured by the digital probe 14 is the distance from the surface hardening portion 13 to the standard block gauge 12.

That is, the gap 9 is obtained by the sum of the standard block gauge 12 thickness and the distance measured by the gap teleprecision apparatus.

Hereinafter, the gap remote precision measuring method by the gap remote precision measuring apparatus of this invention is demonstrated in detail.

The digital probe 14 is connected to the core support barrel projection 7 through the lower penetrating portion of the core barrel 3 and the lower support structure 4 and is mounted to the probe insert 10 by the digital probe fixture 15.

At the time of mounting, the minimum measurable range of the digital probe 14 is ensured so that the process of matching the surface hardened portion 13 of the core support cylinder 2 with the end of the digital probe 14 (hereinafter, zero adjustment) is possible. shall.

To this end, the end of the digital probe 14 is mounted so as to lie in 1 mm or more from the surface hardening portion 13.

After the digital probe 14 is mounted, power is supplied, the air compressor 34 is driven, and zero adjustment is performed using a computer measurement program.

Zero adjustment is performed by mounting a zero adjustment device which can be in complete contact with the surface hardened portion 13 of the core support cylinder 2, and then driving the digital probe 14 to measure the distance to the zero adjustment device.

When the zeroing is complete, disconnect the cables 20, 22, 23 and hose 29 between the chambers 36, 37, 38 and the computer 27 and the air compressor 34.

Reactor vessel with only computer 27 and air compressor 34 removed, chambers 36, 37, 38 positioned below core support assembly and digital probe 14 mounted on core support protrusion 7 (1) Insert and align the core support barrel assembly inside.

At this time, the core support protrusion 7 is coupled with the reactor vessel protrusion 8 on which the standard block gauge 12 is mounted.

After the alignment is complete, the cables 20, 22, 23 and hose 29 between the chambers 36, 37, 38 and the computer 27 and the air compressor 34 are reconnected.

When the connection is complete, supply power and measure the distance using the measurement program.

Distance measurement can measure all points simultaneously or select any point individually.

Based on the gap 9 obtained by adding the measured distance and the thickness of the standard block gauge 12, the size of the padding is calculated and processed.

After the core supporter assembly is lifted out of the reactor vessel 1, the fabricated padding is mounted in the reactor vessel protrusion groove 11.

After the filling is fitted, the core support assembly is again assembled into the reactor vessel (1) and the distance to the filling is again measured to confirm that the allowable clearance requirements are met.

If it is confirmed that the measured gap 9 satisfies the allowable gap requirements, the core support cylinder combination is taken out of the reactor vessel 1 to remove all the gap teleprecision devices and the core support cylinder combination is returned to the reactor vessel 1. Mount it.

Apparatus and method for the remote teleprecision measuring method having the configuration and operation as described above are not only applied to conventional reactor assembly, but also by integrally welding the core support cylinder 2, the core barrel 3, and the lower support structure 4 integrally. It can be applied to fabricate a reactor by assembling the core bearing assembly of one body.

The apparatus and method for gap remote precision measurement according to the present invention can weld the core support barrel, and the core barrel and the lower support structure before the gap between the reactor vessel and the core support cylinder to make the core support assembly, so that the welding The process can be excluded from the main process, significantly reducing construction air.

In addition, the gap teleprecision measuring apparatus and method of the present invention can measure the gap without the measuring instrument enters the bottom of the reactor vessel, can shorten the time required to measure dozens of points, ensure the reliability of the measured value and objective Verification is possible.

In addition, the gap teleprecision measuring device and method of the present invention can contribute to improved workability by being able to escape from a poor working environment such as a conventional narrow space as all measurements can be performed remotely from the outside of the reactor.

In addition, since the process of assembling and disassembling the core support core and the core support assembly in the reactor vessel is required several times, the polar crane required for the lifting thereof must be used for a long time. The method only requires assembling and disassembling the core support container assembly twice, which greatly shortens the use time of the polar crane, thereby contributing to the productivity increase by utilizing the polar crane for other purposes.

Claims (5)

A reactor comprising a reactor vessel, a core support barrel, a core barrel, and a lower support structure, the reactor comprising: A plurality of digital probes measuring a gap between a plurality of reactor vessel protrusions formed on an inner surface of the reactor vessel and a plurality of core support protrusions formed on an outer surface of the core support protrusion and fitted with the reactor vessel protrusions; A computer connected to the digital probe and displaying and storing the measured value of the gap measured by the digital probe; A solenoid valve controlled by the computer and controlling compressed air supplied to drive the digital probe through an air hose; An air compressor for supplying the compressed air to the digital probe; And Including a standard block gauge inserted into the gap, And the digital probe measures the gap after the core support barrel, the core barrel, and the lower support structure are welded. delete The method of claim 1, One of the reactor vessel protrusions is fitted between two of the core support protrusions, The digital probe is characterized in that 4 to 6 is inserted into one of the core support projections, the gap teleprecision device. (A) a core support cylinder installed inside the reactor vessel and supporting the nuclear fuel assembly, a core barrel installed inside the core support cylinder and surrounding the fuel assembly and a lower portion of the core barrel, the weight of the fuel assembly Welding and assembling a lower support structure for supporting the lower support structure; And (B) after the welding assembly of step (A) is completed, a plurality of reactor vessel protrusions formed on the inner surface of the reactor vessel and the reactor vessel protrusions formed on the outer surface of the core support to prevent the flow of the core support vessel And a standard block gauge is inserted in the gap between the plurality of core support protrusions to be fitted, and measuring the gap with a plurality of digital probes. delete

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