NUCLEAR REACTOR VIBRATION MONITORING DEVICE AND MONITORING METHOD THEREOF

• US 20120285246A1
• Filed: 06/21/2012
• Published: 11/15/2012
• Est. Priority Date: 12/22/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: KURODA, Hidehiko, Ootsubo, Tooru
• Granted Patent: US 9,099,206 B2
• Time in Patent Office: Days
• US Class Current: 73/590
• CPC Class Codes: G01H 17/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups see provisionally also G01H1/00
• CPC Class Codes: G21C 17/003 Remote inspection of vessels, e.g. pressure vessels
• CPC Class Codes: G21C 17/10 Structural combination of fuel element, control rod, reactor core, or moderator structure with sensitive instruments, e.g. for measuring radioactivity, strain
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

According to an embodiment, a nuclear reactor monitoring device comprises: an ultrasonic wave transmission means which is installed on the outside surface of a reactor pressure vessel and transmits ultrasonic pulses to the interior of the reactor pressure vessel; an ultrasonic wave receiving means which is installed on the outside surface of the reactor pressure vessels and receives reflected pulses including ultrasonic waves from the ultrasonic pulses reflected by an inspection object in the reactor pressure vessel; a preprocessing means which specifies and removes the reflected ultrasonic pulses generated in the wall of the reactor pressure vessel from the reflected pulse signal received by the ultrasonic wave receiving means or selectively extracts the reflected pulse signal; and a calculation means which determines the vibration of the inspection object from the reflection pulse signal processed by the preprocessing means in accordance with the observation time of the inspection object.

Claims

1. A reactor vibration monitoring device comprising:

ultrasonic wave transmission means that is installed on an outside surface of a reactor pressure vessel and transmits ultrasonic pulses to an interior of the reactor pressure vessel;

ultrasonic wave receiving means that is installed on the outside surface of the reactor pressure vessel and receives reflected pulses including ultrasonic waves of the ultrasonic pulses reflected by an inspection object in the reactor pressure vessel;

preprocessing means for performing processing to exclude reflected ultrasonic pulses reflected in a wall of the reactor pressure vessel from a reflected pulse signal received by the ultrasonic wave receiving means; and

calculation means for determining vibrations of the inspection object from the reflected pulse signal processed by the preprocessing means based on observation time of the inspection object.

2. The reactor vibration monitoring device according to claim 1, wherein:

the ultrasonic wave transmission means is pulse train generating means for transmitting an ultrasonic pulse train to the reactor pressure vessel; and

the preprocessing means calculates a correlation value between a waveform of the ultrasonic pulse train and the reflected pulse signal at each time.

3. The reactor vibration monitoring device according to claim 1, wherein the preprocessing means performs low frequency component extraction processing of squaring an amplitude of the reflected pulsed signal and then extracting a component having a frequency lower than a predetermined frequency.

4. The reactor vibration monitoring device according to claim 1, wherein the preprocessing means performs extraction processing of identifying or extracting from the reflected pulse signal a time domain where ultrasonic pulses reflected by the inspection object are included, based on positions of the ultrasonic wave transmission means, the inspection object, and the ultrasonic wave receiving means.

5. The reactor vibration monitoring device according to claim 1, wherein the preprocessing means stores a differential processing-specific waveform in advance, and performs differential processing of the reflected pulse signal and the differential processing-specific waveform.

6. The reactor vibration monitoring device according to claim 5, comprising interrupting means for interrupting the ultrasonic pulses transmitted from the ultrasonic wave transmission means for an arbitrary time, between an inner surface of the reactor pressure vessel and the inspection object, and wherein

the preprocessing means stores, as the differential processing-specific waveform, a signal that is received by the ultrasonic wave receiving means with the ultrasonic pulses interrupted by the interrupting means.

7. The reactor vibration monitoring device according to claim 5, comprising:

a partial replica of the reactor pressure vessel; and

replica ultrasonic wave transmission means and replica ultrasonic wave receiving means that are arranged on the partial replica in the same positional relationship as that of the ultrasonic wave transmission means and the ultrasonic wave receiving means, and wherein

the preprocessing means stores, as the differential processing-specific waveform, a signal that is received by the replica ultrasonic wave receiving means when the replica ultrasonic wave transmission means transmits ultrasonic waves to the partial replica.

8. The reactor vibration monitoring device according to claim 1, wherein the preprocessing means identifies the reflected ultrasonic pulses reflected in the wall of the reactor pressure vessel based on a wall thickness of the reactor pressure vessel and attached positions of the ultrasonic wave transmission means and the ultrasonic wave receiving means.

9. The reactor vibration monitoring device according to claim 5, wherein the preprocessing means stores, as the differential processing-specific waveform, the reflected ultrasonic pulses reflected in the wall of the reactor pressure vessel based on a wall thickness of the reactor pressure vessel and attached positions of the ultrasonic wave transmission means and the ultrasonic wave receiving means.

10. The reactor vibration monitoring device according to claim 1, comprising position adjusting means for adjusting a relative position between the ultrasonic wave transmission means and the ultrasonic wave receiving means.

11. A reactor vibration monitoring method comprising:

an ultrasonic wave transmission step in which ultrasonic wave transmission means is installed on an outside surface of a reactor pressure vessel and transmits ultrasonic pulses to an interior of the reactor pressure vessel;

an ultrasonic wave receiving step in which ultrasonic wave receiving means is installed on the outside surface of the reactor pressure vessel and receives reflected pulses including ultrasonic waves of the ultrasonic pulses reflected by an inspection object in the reactor pressure vessel;

a preprocessing step of performing processing to exclude reflected ultrasonic pulses occurring in a wall of the reactor pressure vessel from a reflected pulse signal received by the ultrasonic wave receiving means; and

a calculation step of determining vibrations of the inspection object from the reflected pulse signal processed in the preprocessing step based on observation time of the inspection object.