CN-122018014-A - Method and system for detecting vortex of foreign matters on secondary side of steam generator and processing terminal

CN122018014ACN 122018014 ACN122018014 ACN 122018014ACN-122018014-A

Abstract

The invention relates to a method and a system for detecting foreign matter vortex on the secondary side of a steam generator and a processing terminal, wherein the method comprises the steps of obtaining a first vortex signal; determining whether suspicious objects exist on the secondary side of the steam generator according to the first vortex signals, determining the axial position of the suspicious objects according to the first vortex signals when the suspicious objects exist, acquiring second vortex signals, determining whether the suspicious objects are foreign objects according to the second vortex signals, determining the circumferential fuzzy position of the foreign objects according to the second vortex signals when the foreign objects exist, determining the ferromagnetic type of the foreign objects according to the first vortex signals, acquiring third vortex signals, and determining the circumferential accurate position of the foreign objects according to the third vortex signals. The invention can efficiently, comprehensively and accurately detect whether the foreign matters exist in the secondary side of the steam generator and detect the accurate positions of the foreign matters.

Inventors

DING BOYUAN
DOU CANGXIAN
MEI JINNA
HANG YUHUA
HE YI
ZHAO LEI
MA QIANG
KONG YUYING
LI QINGSHUN
WANG CHUNLEI
GUO KAI
CHEN XIAOLIANG

Assignees

中广核检测技术有限公司
苏州热工研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260326

Claims (10)

1. A method for detecting a secondary side foreign matter vortex of a steam generator, comprising: The method comprises the steps of obtaining a first eddy current signal, wherein the first eddy current signal is obtained by detecting the inside of a steam generator by an eddy current probe at an excitation frequency from low frequency to high frequency; Determining whether suspicious objects exist on the secondary side of the steam generator according to the first vortex signal; when the suspicious object exists, determining the axial position of the suspicious object according to the first eddy current signal, and obtaining a second eddy current signal, wherein the second eddy current signal is obtained by detecting the suspicious object by an electromagnetic field rotating in the low-frequency to high-frequency excitation frequency and direction when the eddy current probe approaches to the axial position; determining whether the suspicious object is a foreign object according to the second eddy current signal; When the foreign matter exists, determining a circumferential blurring position of the foreign matter according to the second eddy current signal, and determining a ferromagnetic type of the foreign matter according to the first eddy current signal; acquiring a third eddy current signal, wherein the third eddy current signal comprises eddy current signals obtained by detecting the eddy current probe after applying additional magnetic fields in different directions on the circumferential fuzzy position; And determining the circumferential accurate position of the foreign matter according to the third vortex signal.
2. The method for detecting foreign object vortex on secondary side of steam generator according to claim 1, wherein determining whether suspicious object exists on secondary side of steam generator according to the first vortex signal comprises: Performing similarity analysis on the first vortex signal and the historical vortex signal to obtain a first similarity representing the similarity degree between the first vortex signal and the historical vortex signal, wherein the historical vortex signal comprises the first vortex signal obtained in the previous overhaul period of the nuclear power plant; And judging whether the first similarity is smaller than a first similarity threshold value, and if so, judging that suspicious objects exist on the secondary side of the steam generator.
3. The method for detecting a foreign object vortex on a secondary side of a steam generator according to claim 1, wherein the determining whether the suspicious object is a foreign object according to the second vortex signal includes: Generating a three-dimensional image from the second eddy current signal; And carrying out signal characteristic recognition on the three-dimensional image to determine whether foreign objects exist.
4. The method for detecting a foreign object vortex on a secondary side of a steam generator according to claim 3, further comprising, after determining a ferromagnetic type of the foreign object: and determining the axial length and the circumferential angle of the contact part of the foreign matter and the corresponding heat transfer pipe according to the three-dimensional image so as to generate preliminary size information of the foreign matter.
5. The method for detecting a foreign object vortex on a secondary side of a steam generator according to claim 1, wherein the determining a ferromagnetic type of the foreign object comprises: The method comprises the steps of obtaining a non-ferromagnetic gallery and a ferromagnetic gallery, wherein the non-ferromagnetic gallery comprises Lissajous figures under the combination of different sizes, shapes and different frequency excitation of various foreign matters made of different non-ferromagnetic materials, and the ferromagnetic gallery comprises Lissajous figures under the combination of different sizes, shapes and different frequency excitation of the various foreign matters made of different ferromagnetic materials; In the first eddy current signal, analyzing the morphological change of the eddy current signal acquired near the axial position from a set low frequency value to a set high frequency value to obtain response data from a low frequency interval to a medium-high frequency interval, wherein the response data comprises a phase; Judging a response interval of the first vortex signal according to the response data; when the response interval is in the low-frequency interval, carrying out similarity analysis on the first eddy current signal and the Lissajous figures included in the ferromagnetic gallery in a polling mode to obtain a plurality of second similarities representing the similarity between the first eddy current signal and the corresponding Lissajous figures; Judging that the foreign matter contains ferromagnetic foreign matter when at least one second similarity is larger than a second similarity threshold value; When the response interval is in the medium-high frequency interval, carrying out similarity analysis on the first eddy current signal and a Lissajous figure included in the non-ferromagnetic gallery in a polling mode to obtain a plurality of third similarity degrees representing the similarity degree between the first eddy current signal and the corresponding Lissajous figure; and judging that the foreign matter contains non-ferromagnetic foreign matter when at least one third similarity is larger than a third similarity threshold value.
6. The method for detecting a secondary side foreign object vortex of a steam generator according to claim 5, wherein the method for generating the lissajous figures in the non-ferromagnetic gallery and the ferromagnetic gallery comprises: Acquiring an eddy current signal of an axial winding probe when a foreign matter test piece with a specific material and a specific size and shape is placed on the outer wall of a heat transfer tube of a steam generator at a specific excitation frequency, so as to obtain a test piece eddy current signal; and generating a Lissajous figure corresponding to the foreign matter test piece according to the test piece vortex signal.
7. The method for detecting a foreign object vortex on a secondary side of a steam generator according to claim 1, wherein the determining a circumferentially accurate position of the foreign object from the third vortex signal includes: comparing the intensity of the eddy current signals when the additional magnetic field is applied in different directions according to the third eddy current signals; Determining the application direction of the additional magnetic field when the strength of the eddy current signal is maximum according to the comparison result; a position between the application direction and an eddy current probe that outputs the third eddy current signal is determined as a circumferentially accurate position of the foreign matter.
8. The method for detecting a secondary side foreign object vortex of a steam generator according to any one of claims 1 to 7, wherein the method for acquiring the first vortex signal includes: In the process that the shaft winding type probe passes through the heat transfer pipe at a first set speed, controlling the shaft winding type probe to work at an excitation frequency from low frequency to high frequency so as to acquire the first eddy current signal; The second eddy current signal acquisition method comprises the steps of controlling the rotary probe to work at an excitation frequency from low frequency to high frequency in the process that the rotary probe passes through the heat transfer tube at a second set speed so as to acquire the second eddy current signal, wherein the second set speed is smaller than the first set speed; the method for acquiring the third eddy current signal comprises the step of controlling a shaft-wound probe arranged at the circumferential fuzzy position to work when a magnetic field generating device is arranged at different positions of the circumferential fuzzy position each time so as to acquire the third eddy current signal, wherein the magnetic field generating device comprises an electromagnet or a strong magnetic probe made of a permanent magnetic material.
9. A processing terminal comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor implements the steam generator secondary side foreign matter vortex detection method according to any one of claims 1 to 8 when executing the computer program.
10. A steam generator secondary side foreign matter vortex detection system, comprising: the processing terminal of claim 9; the shaft winding type probe is used for collecting a first eddy current signal; The rotating probe is used for collecting a second eddy current signal; the magnetic field generating device is used for being matched with the shaft winding type probe to acquire a third eddy current signal, wherein the magnetic field generating device comprises an electromagnet or a strong magnetic probe made of a permanent magnetic material.

Description

Method and system for detecting vortex of foreign matters on secondary side of steam generator and processing terminal Technical Field The invention relates to the technical field of overhauling of steam generators of nuclear power plants, in particular to a method and a system for detecting secondary side foreign matter vortex of a steam generator and a processing terminal. Background The steam generator of the nuclear power plant can generate foreign matters in the manufacturing, overhauling and operating stages, and the foreign matters on the secondary side of the steam generator are one of the main reasons for abrasion and degradation of the heat transfer tube. Therefore, during nuclear power plant shutdown maintenance, the secondary side sludge deposit is generally rinsed with water, then the ITV video inspection is performed, and if foreign matters are found, the foreign matters are taken out by a special tool, and technical evaluation is performed when the foreign matters cannot be taken out. However, the cleaning work is difficult to thoroughly clean the foreign matters, and is limited by factors such as complex structure and narrow space of the inspection area, and the ITV video inspection has an inspection blind area, for example, the areas such as a high-level supporting plate, a splitter plate and the like may have a visual field blind area, so that part of the foreign matters cannot be found. Therefore, a technical scheme capable of comprehensively and accurately scanning whether foreign matters exist near each heat transfer tube and accurately positioning the foreign matters is needed in a nuclear power plant. Disclosure of Invention The invention aims to solve the technical problem of providing a method and a system for detecting vortex of foreign matters on the secondary side of a steam generator and a processing terminal. The technical scheme adopted by the invention for solving the technical problems is that a method for detecting the vortex of foreign matters on the secondary side of a steam generator is constructed and comprises the following steps: The method comprises the steps of obtaining a first eddy current signal, wherein the first eddy current signal is obtained by detecting the inside of a steam generator by an eddy current probe at an excitation frequency from low frequency to high frequency; Determining whether suspicious objects exist on the secondary side of the steam generator according to the first vortex signal; when the suspicious object exists, determining the axial position of the suspicious object according to the first eddy current signal, and obtaining a second eddy current signal, wherein the second eddy current signal is obtained by detecting the suspicious object by an electromagnetic field rotating in the low-frequency to high-frequency excitation frequency and direction when the eddy current probe approaches to the axial position; determining whether the suspicious object is a foreign object according to the second eddy current signal; When the foreign matter exists, determining a circumferential blurring position of the foreign matter according to the second eddy current signal, and determining a ferromagnetic type of the foreign matter according to the first eddy current signal; acquiring a third eddy current signal, wherein the third eddy current signal comprises eddy current signals obtained by detecting the eddy current probe after applying additional magnetic fields in different directions on the circumferential fuzzy position; And determining the circumferential accurate position of the foreign matter according to the third vortex signal. Preferably, the determining whether the suspicious object exists on the secondary side of the steam generator according to the first vortex signal includes: Performing similarity analysis on the first vortex signal and the historical vortex signal to obtain a first similarity representing the similarity degree between the first vortex signal and the historical vortex signal, wherein the historical vortex signal comprises the first vortex signal obtained in the previous overhaul period of the nuclear power plant; And judging whether the first similarity is smaller than a first similarity threshold value, and if so, judging that suspicious objects exist on the secondary side of the steam generator. Preferably, the determining whether the suspicious object is a foreign object according to the second eddy current signal includes: Generating a three-dimensional image from the second eddy current signal; And carrying out signal characteristic recognition on the three-dimensional image to determine whether foreign objects exist. Preferably, after determining the ferromagnetic type of the foreign matter, further comprising: and determining the axial length and the circumferential angle of the contact part of the foreign matter and the corresponding heat transfer pipe according to the three-dimensional image so as to generate pr