KR100911768B1 - Pipe inspection gauge by using radioisotope - Google Patents

Abstract

The present invention relates to a pipe inspection apparatus using a radioisotope, and in particular, radioisotopes emitting neutrons and radiation detectors for detecting gamma rays emitted through nuclear reaction with elements outside the neutron and the pipe inspection apparatus are sequentially arranged. A multi-channel coefficient and data storage device for storing data detected from the radiation detector, a power supply device, and a position detection transmitter interlocking with the first housing and the first housing, By including the second housings arranged in sequence, it is applicable to non-metallic pipes and provides information about the surrounding medium even when leakage does not occur if leak points can be detected for pipes that have leaks. This has the advantage of improving the accuracy of the measurement data.

Radioisotopes, radiation detectors, multichannel counting and data storage devices, position transmitters. 1st housing, 2nd housing

Description

Pipe inspection gauge by using radioisotope

The present invention relates to a pipe inspection device using a radioisotope, and more particularly, a radioisotope emitting neutrons and a radiation detector for detecting gamma rays emitted through a nuclear reaction with elements outside the pipe inspection device with neutrons sequentially. A first housing inherent to be arranged in a multi-channel coefficient, a data storage device for storing the data detected from the radiation detector, a power storage device, and a position detection for interlocking with the first housing. By including the second housing inherently arranged so that the transmitters are arranged in sequence, it is applicable to non-metallic pipes. The benefit of providing information increases the accuracy of the measurement data. Relates to a pipe inspection apparatus using a radioisotope.

In general, local leakage of landfill piping can result in economic losses as well as fatal environmental pollution. In general, non-destructive inspections are carried out in the construction of oil pipelines. However, there is currently no method for diagnosing the damage of landfill pipes except for intelligent pipe inspection gauges.

In general, the intelligent pipe inspection device targets large and medium-sized pipes of several tens of kilometers or more, and the diagnosis cost is also very expensive since it is commissioned by a foreign specialized company.

Above all, environmental standards have been strengthened recently, and oil refineries and petrochemical plants require legal inspections for leaks from medium- and small-sized pipelines buried in the past. Intelligent pipe inspection system is used to diagnose corrosion damage of medium and long distance pipes. The intelligent pipe inspection device is developed by Pipetronics in Germany, PII in the UK, GE Inspection in the US, and Asia Protec in Japan to develop an intelligent pipe inspection device using Ultrasonic, Magnetic Flux Leakage principles. Monopolized.

In Korea, the Korea Gas Corporation R & D Center has been investing huge research budget to develop intelligent pipe inspection system.

On the other hand, recently, there is a tendency to replace traditional metal pipes with polyurethane or polyethylene due to problems such as corrosion, but it is difficult to apply ultrasonic waves due to large attenuation in nonmetal materials, and in the case of leakage magnetic flux to ferromagnetic metal materials. In the case of limited and distributed minerals around the landfill pipe, the accuracy of the measurement becomes poor. For non-metallic pipes, the intelligent pipe inspection device using the ultrasonic and leakage magnetic flux principle is almost impossible to apply.

 In addition, a method of detecting leakage of a landfill pipe using a radioactive tracer is also being implemented. If a radiotracer is used, the isotopic leak labeling should be followed by a pipe tester with a built-in radiation short channel analysis instrument. More specifically, after filling a certain portion of the pipe with radioactive isotopes and applying pressure to cause random leakage, removing isotopes inside the pipe, and detecting the isotopes remaining in the surrounding soil outside the pipe by leakage. As such, this method requires additional equipment such as tracer continuous input device and tracer storage container, and it causes an impractical problem in terms of radiation safety management that requires the use of a large amount of radioisotopes.

1 is a diagram illustrating a pressurized state after the radioactive tracer according to the prior art is introduced into a pipe, and FIG. 2 illustrates a state in which the concentration of the radioactive tracer is increased at a leakage position when the radioactive tracer according to the prior art is introduced into a pipe. 3 is a graph showing a marker source peak and a leakage peak when using a radioactive tracer according to the prior art.

Pipe inspection apparatus using a radioactive tracer according to the prior art may use a pipe inspection device (Pipe Inspection Gauge, hereinafter referred to as PIG) technology using a radioisotope tracker.

In order to apply the above technique, the oil pipe suspected of leaking should first be emptied. After that, as shown in Figure 1, the radioactive tracer is put into the underground landfill pipeline, and then the pressure is blocked after closing the end of the pipeline. Then, as shown in FIG. 2, the radiotracer penetrates into the leaking position, thereby increasing the concentration of the radiotracer in the leaking portion. After that, empty the inside of the pipeline again. A pipe inspection device (PIG) having a radiation measuring device is placed inside a pipe, and a pressure is measured to measure a point where the concentration of the tracer is high while moving the position of the pipe inspection device (PIG).

As shown in FIG. 3, when leakage exists in the oil pipe, the concentration of radioactive isotopes is increased in the leaked portion, thereby indicating whether leakage occurs. The leakage location is determined by placing a small source of radioactive marker source at regular intervals and attaching it on an oil pipe. The leak location can be known as the point passing through each marker source and the detail point of the leak location can be calculated by the marker source order and the pipe inspection device (PIG) moving speed.

As such, there is an advantage that a pipe inspection device (PIG) using a radiotracer is very simple, but the radiotracer should be diluted to a detectable concentration in a transport medium, and a long amount of radioisotope should be used for a long distance pipeline. For this purpose, a large amount of storage containers for the storage and recovery of the radioactive tracer are required, and the experimental process is very complicated.

The present invention is applicable to non-metallic pipes, and if the leakage point can be detected for a pipe that leaks, the radioactivity has the advantage of improving the accuracy of the measurement data by providing information on the medium surrounding the pipe even when there is no leakage. An object is to provide a pipe inspection device using isotopes.

According to the present invention, a pipe inspection apparatus using a radioisotope includes a radioisotope that emits neutrons and a radiation detector that detects gamma rays emitted through a nuclear reaction with elements outside the neutron and the pipe inspection apparatus. 1, a multi-channel coefficient and data storage device for storing the data detected from the radiation detector, the power supply and the position detection transmitter interlocked with the first housing and arranged in sequence Including a second housing.

The first housing and the second housing may be interlocked by a ball joint.

In addition, a predetermined length is provided between the radioisotope and the radiation detector so that the radioisotope is installed at the tip, the radiation detector is inherent, and a neutron and a gamma ray accompanying the generation of neutrons directly reach the radiation detector. Lead-containing polyethylene shield is installed may be provided with a third housing of the aluminum material embedded in the first housing.

The polyethylene shield may be arranged in line with the radioisotope and the radiation detector.

In addition, the front and rear ends of the first and second housings may be provided with an adapter ring formed of a circular plate sized pipe inner diameter so that the first and second housings can be forwarded by the air pressure supplied from the rear surface.

A rubber packing may be installed along the outer circumferential surface of the adapter ring in order to prevent leakage of air supplied from the rear surfaces of the first and second housings.

The data detected by the radiation detector may be transmitted to the multi-channel coefficient and data storage device by a cable connected to a first connector installed at the rear end of the first housing and a second connector installed at the front end of the second housing. Can be.

The pipe inspection device using the radioisotope according to the present invention is applicable to non-metallic pipes and can be measured by providing information on the surrounding medium of the pipe even if leakage can be detected for the pipe where leakage occurs. The accuracy of the data is improved.

The present invention relates to a radioactive isotope that emits neutrons and a radiation detector that detects gamma rays emitted through nuclear reaction with elements outside the neutron and the pipe inspection device. And a multi-channel coefficient and data storage device for storing the data detected from the radiation detector, a power supply, and a second housing inherently arranged so that a position detecting transmitter for emitting electromagnetic waves is arranged in order to determine the position. Provide a pipe inspection system using isotopes.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In addition, the present embodiment is not intended to limit the scope of the present invention, but is presented by way of example only, and various modifications may be made without departing from the technical gist of the present invention.

Figure 4a is a side view showing a pipe inspection device using an isotope according to the present invention, Figure 4b is a front view showing a pipe inspection device using an isotope according to the present invention, Figure 5 is a multi-channel coefficient and data according to the present invention A block diagram showing the radiation measurement of a storage device.

As shown in Figure 4a and 4b, the pipe inspection apparatus 100 using the radioisotope according to the present invention is the radioisotope 21 and the neutron emitted from the radioisotope 21 and neutron emission The radiation detector 24, which detects gamma rays generated through nuclear reaction with elements outside the pipe inspection device, is interlocked with the first housing 10 and the first housing 10, which are arranged in sequence, and the radiation detector ( A multi-channel coefficient and data storage device 32 for storing the data detected from the device 24, the power supply device 33, and a position detection transmitter 34 for emitting electromagnetic waves in order to determine the position. And two housings 30.

Here, as shown in FIG. 5, the multi-channel coefficient and data storage device 32 includes a data storage function as a function of a general multi-channel analyzer. The data storage device uses Compact Flash. In the measurement data, the measurement values of each channel are recorded at sampling intervals.

In addition, when the pipe inspection device (PIG) 100 inserted in the pipe is not recovered for some reason and adhered to the pipe, a very big problem occurs. This is the same as the conventional pipe inspection device as well as the pipe inspection device (PIG) 100 using the isotope according to the present invention and the recovery of the pipe inspection device (PIG) 100 must be made. In the worst case, since the buried pipe should be excavated, the position of the pipe inspection apparatus 100 should be detected, and for this purpose, a position detecting transmitter 34 for emitting electromagnetic waves is inserted. The position detection transmitter 34 has many manufacturers and there are various kinds of products according to the size of each pipe.

By constructing the pipe inspection apparatus 100 using the radioisotope according to the above and the present invention, it is applicable to non-metallic pipes, and even if the leakage point can be detected for the pipes where leakage occurs, even if there is no leakage, Providing information about the medium has the advantage that the accuracy of the measurement data is improved.

The first housing 10 and the second housing 30 may be interlocked by the ball joint 50. Connected to bend to the ball joint 50 as described above is configured to pass through the bent portion of the pipe.

The radioisotope 21 is installed at the tip, the radiation detector 24 is inherent, and the neutrons generated by the radioisotopes and gamma rays generated with neutrons are prevented from directly reaching the radiation detector 24. For this purpose, a polyethylene shield 22 having a predetermined length is provided between the radioisotope 21 and the radiation detector 24. In addition, some neutron-emitting radioisotopes 21 are accompanied by gamma-ray emission, so that a predetermined length within the polyethylene shield 22 is prevented from directly reaching the radiation detector 24 by gamma rays generated from the radioisotopes 21. Lead shield 23 having a lead material may be installed. The polyethylene shield 22 is made of aluminum and is embedded in the third housing 20. The third housing 20 is embedded in the first housing 10.

Between the radioisotope 10, in particular, the neutron source and the radiation detector 24, a shield made of polyethylene and lead is formed in the form of a sandwich. This is to prevent the neutron rays and gamma rays generated from the neutron source directly reach the radiation detector 24, and polyethylene serves to shield neutron rays and lead to gamma rays. In particular, in case of Am241, lead shielding is essential as it carries 4.43MeV gamma ray when neutron is generated.

In addition, the polyethylene shield 22 may be arranged in a line with the radioisotope 21 and the radiation detector 24.

Both front and rear ends of the first and second housings 10 and 30 are round plates having a pipe inner diameter so that the first and second housings 10 and 30 can be moved forward by the air pressure supplied from the rear surface. The formed adapter ring 40 may be installed. The neutron source generated by the pipe inspection device 100 interacts with elements around the movement path while controlling the moving speed of the pipe inspection device 100 by the air pressure supplied from the rear of the pipe inspection device 100. Get up.

In addition, the rubber packing 45 may be installed along the outer circumferential surface of the adapter ring 40 to prevent leakage of air supplied from the rear surfaces of the first and second housings 10 and 30.

Data detected by the radiation detector 24 is a cable connected to the first connector 12 installed in the rear end of the first housing 10 and the second connector 31 provided in front of the second housing 30. 60 may be transmitted to the multi-channel coefficients and data storage 32.

Referring to the operation of the pipe inspection apparatus using a radioisotope according to the present invention configured as described above are as follows.

6 is a diagram showing a radioactive capture process, Figure 7 is a schematic diagram showing a method for measuring the component around the pipe using the instantaneous gamma ray radiation analysis.

As shown in FIG. 6 and FIG. 7, an apparatus using instantaneous gamma ray radiation analysis (hereinafter referred to as PGNAA) is widely used to obtain information about coal deposits in open cut mines. C _n H _{m In} case of leakage of pipeline such as oil pipeline or petrochemical facility, leakage can be detected by the following principle. In case of leakage, the periphery of the pipe forms an oil band. The oil consists of a combination of C _n H _m hydrocarbons. Soil, on the other hand, has relatively low hydrogen and carbon content. Therefore, it is possible to know whether the oil pipe is leaked by the presence of a specific amount of carbon and hydrogen.

The detection principle of the pipe inspection device 100 using the radioisotope according to the present invention is as follows.

The reaction between the neutron and the nucleus is classified as follows.

The kinetic energy of neutrons and nuclei is exchanged, the nucleus is not lifted, the kinetic energy is preserved, and the energy loss is maximized in neutron collisions. Inelastic scattering, which emits gamma rays and returns to the ground state, radioactive capture that occurs effectively at low neutrons below 1 keV, and charged particle emission that absorbs neutrons and generates alpha or protons Charged-Particle Reaction, Neutron-producing Reactions, and Fission reactions that are absorbed by fissile such as ²³⁵ U and ²³⁹ Pu to cause fission.

As shown in FIG. 6, gamma rays are emitted by neutron inelastic scattering and radioactive capture during the interaction between the neutron and the nucleus, and the energy of the gamma rays emitted at this time varies depending on the element. Using this property, the component of an element can be known by analyzing the energy of the emitted gamma rays. Using this principle, there are various application technologies such as neutron emission analysis (NAA), PGNAA borehole logging, and PGNAA on-belt analyzer.

As shown in FIG. 7, the radioactive capture reaction is caused by thermal neutrons, whereas neutron inelastic scattering is caused by fast neutrons of several MeV bands which are not decelerated among neutrons generated from radioactive isotopes such as Am-Be or ²⁵² Cf. .

Petroleum and petrochemical products contain many hydrogen and carbon atoms. The high-speed neutrons generated by the radioisotope are decelerated mainly by elastic collision with the hydrogen atom nucleus and change into thermal neutrons. Therefore, the results of the spectrum measurement of the radioactive capture reaction using a high-speed neutron source to organic materials such as water and hydrocarbons containing a large amount of hydrogen atoms and of inorganic materials not containing a large amount of hydrogen atoms Represents a significant difference in energy efficiency as well as detection efficiency.

However, if the surrounding area is rich in hydrogen atoms such as groundwater, similar results can be obtained. In this case, it is necessary to classify the overall spectral shape through the spectral differences according to the hydrogen atoms and other atomic composition ratios. Therefore, multichannel analysis is essential in detecting radiation. Differences from leaky and normal moisture environments include radioactive capture for hydrogen and inelastic scattering peaks for carbon or oxygen atoms that are common in water composition (H ₂ O) and dairy components (C _n H _m ). It can be seen through.

8 is a table showing instantaneous gamma-ray energy for major elements.

Looking at the radioisotope of the pipe inspection device 100 using a radioisotope according to the present invention.

⁹ Be + α ⇒ ¹² C + n + γ (4.43MeV)

Formula 1 represents a (α, n) reaction. Α is alpha ray, n is neutron, and γ is gamma ray.

The neutron source used in the PGNAA test, for example in the resource industry, uses neutron sources based on (α, n) reactions and spontaneous fission, such as ²⁵² Cf. The source of neutrons based on the (α, n) reaction used in the resource industry is Am-Be, which is the source of high-speed neutrons, and the ¹² C generated during the (α, n) reaction is excited. Accompanied by gamma radiation release. If the alpha rays emitted by Am target ⁹ Be, then about 70 to 80 neutrons are emitted per 10 ⁶ alpha particles.

In addition to Am-Be, ²⁵² Cf, which is widely used in the resource industry, produces neutron fluxes of 2.3 ㅧ 10 ⁶ n / s per microgram. In the resource industry, in the case of analyzers using nuclear reactions, ²⁵² Cf is preferred when the main element to be analyzed causes radioactive capture, and neutron sources based on (α, n) are preferred when the element causes the nuclear reaction by neutron inelastic scattering. . This is because neutron capture requires low energy thermal neutrons and neutron inelastic scattering requires high energy neutrons.

9 is a table comparing neutron generators.

10 is a diagram showing an oil leakage environment around piping.

Looking at the leak detection measurement of the pipe inspection device using a radioisotope according to the present invention.

When leakage occurs, as shown in FIG. 10, the periphery of the pipe forms an oil band. Leakage detection should be detectable for oil leaks around the pipe, no leaks, no oil leaks, and high levels of groundwater and hydrogen. For buried pipe without the oil leakage around the medium is soil, such as inorganic materials and in general five days common band (band oil) of oil is composed of a combination of C _n H _m. When leakage occurs, the soil is relatively low in hydrogen and carbon. Using a pipe tester with a built-in analysis device through the neutron nuclear reaction, it is possible to determine the leakage of oil around the pipe by measuring the abundance ratio of hydrocarbons with soil.

Looking at the data analysis method of the pipe inspection device 10 using a radioisotope according to the present invention.

FIG. 11 is a graph showing a gamma ray spectrum generated from the neutron source of Am241 for polypropylene which is a kind of hydrogen and carbon hydride compound in the absence of a scattering medium and soil containing 14% water, and FIG. 12 is a buried tube A graph of energy distribution for the major elements that are likely to be detected in the surrounding medium.

The energy of gamma rays emitted during the scattering process as a result of the interaction between neutrons and the elements that make up the surrounding medium varies depending on the type of medium, and in particular, shows abnormally high concentrations of hydrogen (H) in the moving zone. The area can be detected, and the increase in hydrogen concentration is directly related to the leakage or leakage of the pipe, so that an area with a high possibility of leakage can be identified. The gamma ray spectrum generated from the neutron source of Am241 when there is no scattering medium is shown in FIG. 11.

Am241 emits 4.3 MeV of gamma rays by ⁹ Be + α ⇒ ¹² C + n + γ (4.3MeV) when neutrons are generated by the (α, n) reaction. When gamma rays are measured, they are accompanied by a single escape peak and a double escape peak, resulting in 4.3MeV, 3.8MeV, and 3.28MeV peaks. Therefore, in the PGNAA spectrum measurement by the medium, sufficient shielding should be inserted between the neutron source and the detector so that the gamma ray peak generated directly from the neutron source is not measured together.

The presence or absence of hydrogen can be determined by detecting the peak of the energy band of 2.23 MeV from the measurement result. In FIG. 11, it can be seen that a peak is measured at an energy of 2.23 MeV in the case of wet soil.

As shown in FIG. 11, in the case of hydrocarbons, peaks due to the hydrogen component are smaller than those of water. The neutron source slowed down by the hydrogen component becomes a thermal neutron, causing a nuclear reaction with the constituents of the medium to give gamma rays of various energies.

1 is a view showing a pressurized state after the radioactive tracer according to the prior art in the pipe;

2 is a view showing a state in which the concentration of the radiotracer in the leakage position when the radioactive tracer according to the prior art is introduced into the pipe,

3 is a graph showing a marker source peak and a leakage peak when using a radioactive tracer according to the prior art;

Figure 4a is a side view showing a pipe inspection apparatus using an isotope according to the present invention,

Figure 4b is a front view showing a pipe inspection apparatus using an isotope according to the present invention,

5 is a block diagram showing radiation measurement of a multi-channel coefficient and data storage device according to the present invention;

6 is a view showing a radioactive capture process,

7 is a schematic view showing a method for measuring the composition around the pipe using an instantaneous gamma ray radiation analysis;

8 is a table showing gamma ray energy generated during neutron and nuclear reactions for major elements.

9 is a table comparing the neutron generator,

10 is a view showing an oil leakage environment around piping;

11 is a graph showing a gamma ray spectrum generated from the neutron source of Am241 for the polypropylene, which is a kind of hydrogen and carbon hydrogen compound, in the absence of a scattering medium and 14% of moisture.

12 is a graph of energy distribution for major elements that may exist around the landfill pipe.

<Explanation of symbols on main parts of the drawings>

10: first housing 12: first connector

20: Third housing 21: Radioactive isotopes

22: polyethylene shield 23: shield

24: radiation detector 30: second housing

31: second connector 32: multi-channel coefficient and data storage device

33: power supply 34: position transmitter

40: adapter ring 45: rubber packing

50: ball joint 60: cable

Claims (7)

A first housing in which a radioactive isotope emitting neutrons and a radiation detector for detecting gamma rays emitted through nuclear reactions with elements outside the neutron and pipe inspection apparatus are arranged in sequence; A multi-channel coefficient and data storage device for storing the data detected from the radiation detector, a power supply device, and a position detection transmitter for emitting an electromagnetic wave for locating the first housing. 2 housing; Radioactive isotopes, characterized in that the front and rear ends of the first and second housings are provided with an adapter ring formed of a circular plate of a pipe inner diameter so that the first and second housings can be moved forward by the air pressure supplied from the rear surface. Pipe inspection device using. The method according to claim 1, The first housing and the second housing is a pipe inspection apparatus using a radioisotope, characterized in that the interlocking by ball joint. The method according to claim 1, The radioisotope is installed at the tip, the radiation detector is inherent, and a neutron and a predetermined length between the radioisotope and the radiation detector in order to prevent the gamma rays accompanying the generation of neutrons directly reach the radiation detector. Leaded polyethylene shield is installed, the pipe inspection device using a radioactive isotope equipped with a third housing of the aluminum material inherent in the first housing. The method according to claim 3, The polyethylene shield is a pipe inspection device using a radioisotope arranged in a line with the radioisotope and the radiation detector. delete The method according to claim 1, And a rubber packing is installed along an outer circumferential surface of the adapter ring in order to prevent leakage of air supplied from the rear surfaces of the first and second housings. The method according to claim 1, Data detected by the radiation detector is transmitted to the multi-channel coefficient and data storage device by a cable connected to a first connector installed at the rear end of the first housing and a second connector installed at the front end of the second housing. Pipe inspection device using radioisotopes.

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