Flow condition monitor

• US 6,480,793 B1
• Filed: 10/27/2000
• Issued: 11/12/2002
• Est. Priority Date: 10/27/2000
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Martin, Clifford B.
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US09/697,725
• Time in Patent Office: 746 Days
• Field of Search: 702/40, 702/43, 702/45, 702/50-51, 702/54-55, 702/100, 702/104, 738/611.8, 738/611.9, 738/612, 738/612.3, 738/612.5, 376/246, 376/249, 376/258
• US Class Current: 702/45
• CPC Class Codes: G01F 1/704 using marked regions or existing inhomogeneities within the fluid stream, e.g. statistically occurring variations in a fluid parameter G01F1/76, G01F25/00 take precedence
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G21C 17/032 Reactor-coolant flow measuring or monitoring measuring volume or mass flow in general G01F
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A system and method of detecting and monitoring flow conditions in the coolant of a nuclear reactor that relies upon acoustic or optical differences in the various flow conditions. The system uses a database of acoustic or optical characteristics of the various known flow conditions being monitored, and a processor that compares the detected acoustic signals with the known acoustic characteristics. The processor uses various methods of discrimination, such as altering or decaying the transmitted signal, to aid in the interpretation and comparison of the signals. The acoustic detection is provided by a pair of sensor assemblies positioned a distance from each other to detect variations in the acoustic patterns associated with the coolant flow. A transmitter and receiver of each sensor assembly can be positioned on opposite sides of the pipe in which the coolant is flowing, or on the same side of the pipe, depending upon which configuration provides the best discrimination between the flow conditions being monitored. The monitoring system is effective for determining, among other things, the existence of bubbles entrained in the coolant, the existence and level of a free surface, the existence of vortex or whirlpool formations, and the existence of entrained solid particulates.

Claims

1. A flow condition monitoring system for monitoring fluid flow conditions in a nuclear power plant, comprising:

a first sensor assembly positioned near a fluid flow to be monitored, said sensor assembly having an output signal;

a database containing known output signal characteristics of various fluid flow conditions being monitored; and

a processor means connected to said first sensor assembly and to said database for receiving and comparing the signal from the sensor assembly with the known characteristics contained in the database to determine a condition of the fluid flow.

2. The flow condition monitoring system of claim 1, wherein said sensor assembly comprises an acoustic receiver for detecting acoustic characteristics of the fluid flow, and said database contains known acoustic characteristics of the various fluid flow conditions being monitored.

3. The flow condition monitoring system of claim 2, wherein said sensor assembly further comprises an acoustic transmitter positioned adjacent to the fluid flow to enhance the acoustic characteristics detected by said acoustic receiver.

4. The flow condition monitoring system of claim 3, wherein said transmitter and said receiver are positioned on opposite sides of the fluid flow from each other.

5. The flow condition monitoring system of claim 3, wherein said transmitter and said receiver are positioned on the same side of the fluid flow.

6. The flow condition monitoring system of claim 1, further comprising a second sensor assembly spaced from said first sensor assembly, said second sensor assembly having a second output signal, and said processor means compares said second output signal to said first output signal to determine a location of a disturbance detected by the first sensor assembly.

7. The flow condition monitoring system of claim 1, further comprising a filter connected between said sensor assembly and said processor for removing undesired noise from said output signal.

8. The flow condition monitoring system of claim 1, further comprising a display device connected to said processor means for communicating said determined fluid flow condition to a nuclear plant operator.

9. The flow condition monitoring system of claim 1, wherein said fluid flow conditions being monitored include the existence of entrained bubbles and solid particulates in the fluid flow.

10. The flow condition monitoring system of claim 9, wherein said fluid flow conditions being monitored further include a free surface and a vortex condition in the fluid flow.

11. A flow condition monitoring system for monitoring fluid flow conditions in a nuclear power plant comprising:

a first sensor assembly comprising a laser beam transmitter and receiver for detecting optical characteristics in the fluid flow, and

a database containing known optical characteristics of the various fluid flow conditions being monitored; and

a processor means connected to said first sensor assembly and to said database for receiving and comparing the signal from the sensor assembly with the known characteristics contained in the database to determine a condition of the fluid flow.

12. A flow condition monitoring system for monitoring the coolant flow in a shutdown cooling system drain pump of a nuclear power plant during midloop operation, comprising:

a main pipe to conduct coolant from a nuclear reactor to a steam generator, said main pipe being substantially horizontal and having an upper region and a lower region;

a drain pipe connected at the lower region of the main pipe to conduct coolant from the lower region to a drain pump;

a first sensor assembly positioned near the drain pipe for detecting acoustic signals from a coolant flow within the drain pipe;

a database of known acoustic signal characteristics of various flow conditions being monitored; and

a processor that compares the detected acoustic signals with the known acoustic characteristics contained in the database to identify a coolant flow condition.

13. The flow condition monitoring system of claim 12, wherein said first sensor assembly comprises an acoustic signal transmitter to enhance the acoustic signals detected by said acoustic receiver.

14. The flow condition monitoring system of claim 12, wherein said transmitter and said receiver are positioned on opposite sides of the drain pipe from each other.

15. The flow condition monitoring system of claim 12, further comprising a second sensor assembly for detecting acoustic signals from the coolant flow within the drain pipe, said second sensor assembly being spaced from said first sensor assembly, and said processor comprising a means for comparing the detected acoustic signals from said second sensor assembly to the detected acoustic signals from said first sensor assembly to assist identification of the flow condition by monitoring the variation or attenuation of the signals in time and distance.

16. The flow condition monitoring system of claim 12, wherein said fluid flow conditions being monitored include the existence of entrained bubbles and solid particulates in the fluid flow.

17. The flow condition monitoring system of claim 16, wherein said fluid flow conditions being monitored further include a free surface and a vortex condition in the fluid flow.

18. A method of monitoring flow conditions in a nuclear power plant, comprising the steps of:

positioning a first sensor assembly near a fluid flow to be monitored;

generating a first output signal by said first sensor assembly indicative of a fluid flow condition;

providing a database containing known output signal characteristics of various fluid flow conditions being monitored; and

comparing said first output signal with the known characteristics of various fluid flow conditions to identify the fluid flow condition.

19. The method of monitoring flow conditions according to claim 18, wherein the plant includes a main pipe to conduct coolant from a nuclear reactor to a steam generator, said main pipe being substantially horizontal and having an upper region and a lower region with a drain pipe connected at the lower region of the main pipe to conduct coolant from the lower region to a drain pump, and said positioning step comprises positioning the first sensor assembly near an intersection of said drain pipe and said main pipe.

20. The method of monitoring flow conditions according to claim 19, further comprising the step of adjusting a coolant flow level in response to the identified fluid flow condition.

21. The method of monitoring flow conditions according to claim 18, wherein said sensor assembly comprises an acoustic receiver, and said generating step comprises generating a first output signal by said first sensor assembly based on an acoustic pattern emanating from the fluid flow.

22. The method of monitoring flow conditions according to claim 21, further comprising the step of placing an acoustic transmitter near the fluid flow and transmitting ultrasonic signals to enhance the acoustic patterns detected by said acoustic receiver.

23. The method of monitoring flow conditions according to claim 18, further comprising the steps of:

positioning a second sensor assembly near the fluid flow to be monitored;

generating a second output signal by said second sensor-assembly; and

comparing said second output signal to said first output signal assist identification of the flow condition by monitoring the variation of the signals in time and distance.

24. The method of monitoring flow conditions according to claim 18, wherein said fluid flow conditions being monitored include the existence of entrained bubbles and solid particulates in the fluid flow.

25. The method of monitoring flow conditions according to claim 24, wherein said fluid flow conditions being monitored further include a free surface and a vortex condition in the fluid flow.