Method of detecting an existence of a loose part in a steam generator of a nuclear power plant

Patent metadata

Field	Value
Publication number	US-12537112-B2
Application number	US-202117152157-A
Country	US
Kind code	B2
Filing date	Jan 19, 2021
Priority date	Apr 7, 2011
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

A plurality of signal anomalies are identified in a number of tubes in a steam generator. Since the geometry of the steam generator is known, the location of each signal anomaly along each tube is converted into a location within the interior of the steam generator. If a plurality of signal anomalies are at locations within the steam generator that are within a predetermined proximity of one another, such a spatial confluence of signal anomalies is determined to correspond with a loose part situated within the steam generator. Additional methodologies can be employed to confirm the existence of the loose part. Historic tube sheet transition signal data can be retrieved and subtracted from present signals in order to enable the system to ignore the relatively strong eddy current sensor signal of a tube sheet which would mask the relatively weak signal from a loose part at the tube sheet transition.

First claim

What is claimed is:

1 . A method of non-destructively detecting an existence of a loose part within a steam generator of a nuclear power plant, the steam generator having a plurality of tubes within an interior thereof, the method comprising:
detecting, via an eddy current sensor, a first eddy current indicative of an electromagnetic field through the eddy current sensor; generating, via the eddy current sensor, a first eddy current signal indicative of the detected eddy current; processing, via a processor, the first eddy current signal to detect a first signal anomaly at a first tube position along a first tube from among the plurality of tubes; converting the first tube position along the first tube into a three-dimensional first anomaly location within the interior of the steam generator; detecting, via the eddy current sensor, a second eddy current indicative of an electromagnetic field through the eddy current sensor; generating, via the eddy current sensor, a second eddy current signal indicative of the detected second eddy current; processing, via the processor, the second eddy current signal to detect a second signal anomaly at a second tube position along a second tube from among the plurality of tubes different from the first tube, and converting the second tube position along the second tube into a three-dimensional second anomaly location within the interior of the steam generator; comparing the first anomaly location and second anomaly location; determining that the first anomaly location and the second anomaly location are within a predetermined proximity of one another; determining that a loose part exists in the vicinity of the first and second anomaly locations based at least in part upon the first and second signal anomalies and the determination that the first anomaly location and the second anomaly location are within the predetermined proximity of one another; initiating an inspection of the steam generator in the vicinity of the first and second anomaly locations to determine a degree of damage that has occurred to at least one tube of the plurality of tubes; repairing the at least one tube of the plurality of tubes based on the inspection of the steam generator.

2 . The method of claim 1 , further comprising employing a first type of detection in the identifying of the first and second signal anomalies and, responsive to the determining that a loose part exists, instructing a further analysis of at least the first and second tube positions with a second type of detection different from the first type of detection.

3 . The method of claim 1 , further comprising:
identifying the first and second signal anomalies from a data stream output by a data source that contemporaneously generated the data stream and at least one alternative data stream; and confirming the existence of the loose part by:
identifying from the at least one alternative data stream an alternative first signal anomaly at the first tube position along the first tube, and
identifying from the at least one alternative data stream an alternative second signal anomaly at the second tube position along the second tube.

4 . The method of claim 1 , further comprising detecting as the first signal anomaly a signal change between a signal from a data stream with respect to the first tube position along the first tube and a signal from the data stream with respect to an adjacent tube position along the first tube.

5 . The method of claim 4 , further comprising ignoring a signal change that fails to meet a predetermined threshold.

6 . The method of claim 4 , further comprising ignoring a signal change between a signal from a data stream with respect to the first tube position along the first tube and a signal from the data stream with respect to the adjacent tube position along the first tube when:
at least one of the first tube position and the adjacent tube position is situated adjacent a tube sheet of the steam generator, and the data stream indicates that a minority of the tubes among the plurality of tubes each possess a similar signal change at a similar location therein.

7 . The method of claim 4 , further comprising when at least one of the first tube position and the adjacent tube position is situated adjacent a tube sheet of the steam generator:
retrieving a historic signal change between a previous signal from a previous data stream with respect to the first tube position along the first tube and a previous signal from the previous data stream with respect to the adjacent tube position along the first tube; subtracting the historic signal change from the signal change to generate a net signal change; and employing the net signal change as the first signal anomaly.

8 . The method of claim 1 , further comprising detecting as the first signal anomaly a change between a signal from a data stream with respect to the first tube position along the first tube and a signal from a previous data stream with respect to the first tube position along the first tube.

9 . A machine readable storage medium having stored thereon instructions which, when executed on a processor of a computing device, cause the computing device to perform the operations of claim 1 .

10 . The system of claim 9 , wherein the instructions which, when executed on a processor, further cause the computerized device to determine the nature of the loose part.

11 . The system of claim 9 , wherein the instructions which, when executed on a processor, further cause the computerized device to distinguish the loose part from sludge, based at least in part on the first and second anomaly location.

12 . The method of claim 1 , further comprising determining the nature of the loose part.

13 . The method of claim 1 , further comprising removing the loose part from the steam generator.

14 . A computer which can non-destructively detect an existence of a loose part within a steam generator of a nuclear power plant, the steam generator having a plurality of tubes within an interior thereof, the computer comprising:
a processor; and a memory having stored therein one or more routines comprising instructions which, when executed on a processor, cause the computer to perform operations comprising:
detecting, via an eddy current sensor, a first eddy current indicative of an electromagnetic field through the eddy current sensor, and generating, via the eddy current sensor, a first eddy current signal indicative of the detected eddy current;
identifying in the first eddy current signal a first signal anomaly at a first tube position along a first tube from among the plurality of tubes, and converting the first tube position along the first tube into a three-dimensional first anomaly location within the interior of the steam generator;
detecting, via the eddy current sensor, a second eddy current indicative of an electromagnetic field through the eddy current sensor, and generating, via the eddy current sensor, a second eddy current signal indicative of the detected second eddy current;
identifying in the second eddy current signal a second signal anomaly at a second tube position along a second tube from among the plurality of tubes different from the first tube, and converting the second tube position along the second tube into a three-dimensional second anomaly location within the interior of the steam generator;
making a determination that the first anomaly location and the second generator location are within a predetermined proximity of one another;
determining that a loose part exists in the vicinity of the first and second anomaly locations based

Assignees

• Westinghouse Electric Co Llc

Inventors

• Le Qui V

Classifications

• Y02E30/30

  Nuclear fission reactors · CPC title

• G21D3/001

  Computer implemented control · CPC title

• G21D1/006

  primary side of steam generators (secondary side of steam generators F22B1/00, F22B35/00 or F22B37/00) · CPC title

• G21C19/207 Primary

  Assembling, maintenance or repair of reactor components (G21C3/334 takes precedence) · CPC title

• G01N27/902

  by moving the sensors · CPC title