Support structure detection

• US 10,444,012 B2
• Filed: 11/25/2014
• Issued: 10/15/2019
• Est. Priority Date: 03/30/2012
• Status: Active Grant

• Current Assignee: Atomic Energy of Canada Limited (Government of Canada)
• Original Assignee: Atomic Energy of Canada Limited (Government of Canada)
• Inventors: Craig, Stuart Thomas, Chaplin, Kenneth Robert
• Primary Examiner(s): Breene, John E
• Assistant Examiner(s): Ngo, Dacthang P
• Application Number:
  US14/553,200
• Publication Number:
  US 20150106055A1
• Time in Patent Office: 1,785 Days
• Field of Search: 702157
• CPC Class Codes: G01B 21/14 internal diameters of boreholes or wells E21B47/08
• CPC Class Codes: G21C 1/20 moderator being liquid, e.g. pressure-tube reactor
• CPC Class Codes: G21C 17/00 Monitoring; Testing measuring in general G01; Maintaining
• CPC Class Codes: G21C 17/06 Devices or arrangements for monitoring or testing fuel or fuel elements outside the reactor core, e.g. for burn-up, for contamination G21C17/08, G21C17/10 take precedence; detecting leaking fuel elements during reactor operation G21C17/04
• CPC Class Codes: G21D 3/001 Computer implemented control
• CPC Class Codes: Y02E 30/00 Energy generation of nuclear origin
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

While typically-collected diameter data contains information for detecting some garter springs, many garter springs may not be detected without processing the diameter data. Responsively, a method for processing the diameter data to detect the garter springs has been developed. In particular, the processing involves fitting of the diameter data to a shape, determining residual errors and using the residual errors to locate garter springs.

Claims

1. A method of locating a garter spring external to a pressure tube, said method comprising:

receiving, from a measurement device in said pressure tube, a plurality of data points, where said receiving includes receiving a data point representative of a diameter of said pressure tube at each of a plurality of angular offsets for a first range of axial positions in said pressure tube;

fitting a shape to said plurality of data points;

determining an integrated residual error between said data points and said shape;

associating said integrated residual error with said first range of axial positions;

repeating said receiving, fitting, determining and associating for a further plurality of axial positions, thereby producing a plurality of integrated residual errors;

applying a digital filter to said plurality of integrated residual errors, thereby producing a plurality of filtered integrated residual errors; and

indicating, as a location of said garter spring, an axial position associated with a local maximum filtered integrated residual error among said plurality of filtered integrated residual errors.

2. The method of claim 1 wherein said digital filter comprises a three-stage digital filter.

3. The method of claim 2 wherein a first stage of said three-stage digital filter comprises a 6th order infinite impulse response Butterworth low pass filter, with a 3 dB cut off at 18 mm.

4. The method of claim 2 wherein a second stage of said three-stage digital filter comprises a 4th order finite impulse response derivative filter.

5. The method of claim 2 wherein a third stage of said three-stage digital filter comprises an order 40 finite impulse response step change cross correlation filter.

6. The method of claim 1 wherein said shape is a circle.

7. The method of claim 1 wherein said shape is an ellipse.

8. A device comprising:

a processor adapted to;

receive, from a measurement device in said pressure tube, a plurality of data points, where said processor is adapted to receive a data point representative of a diameter of a pressure tube at each of a plurality of angular offsets for a first range of axial positions in said pressure tube;

fit a shape to said plurality of data points;

determine an integrated residual error between said data points and said shape;

associate said integrated residual error with said first range of axial positions;

repeat said receiving, fitting, determining and associating for a further plurality of axial positions, thereby producing a plurality of integrated residual errors;

digitally filter said plurality of integrated residual errors to, thereby, produce a plurality of filtered integrated residual errors; and

indicate, as a location of a garter spring, an axial position associated with a local maximum filtered integrated residual error among said plurality of filtered integrated residual errors.

9. A computer readable medium containing computer-executable instructions that, when performed by a processor, cause said processor to:

receive a plurality of data points, where said instructions cause said processor to receive a data point representative of a diameter of said pressure tube at each of a plurality of angular offsets for a first range of axial positions in said pressure tube;

fit a shape to said plurality of data points;

determine an integrated residual error between said data points and said shape;

associate said integrated residual error with said first range of axial positions;

repeat said receiving, fitting, determining and associating for a further plurality of axial positions, thereby producing a plurality of integrated residual errors;

digitally filter said plurality of integrated residual errors to, thereby, produce a plurality of filtered integrated residual errors; and

indicate, as a location of a garter spring, an axial position associated with a local maximum filtered integrated residual error among said plurality of filtered integrated residual errors.