Fiber optic temperature sensing system and method utilizing Brillouin scattering for large, well-ventilated spaces

Patent metadata

Field	Value
Publication number	US-9921113-B2
Application number	US-201414338918-A
Country	US
Kind code	B2
Filing date	Jul 23, 2014
Priority date	Jul 23, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A temperature change detection apparatus for monitoring temperature change in various portions of a large space includes a trip logic unit configured to execute a trip operation based on receipt of a trip signal at the trip logic unit; a plurality of temperature sensors each including a sensing portion composed of optical fiber cable and each being configured to generate light information indicating an amount of Brillouin scattering that occurs within the sensing portion; a plurality of monitoring units configured such that each monitoring unit determines a temperature value corresponding to each temperature sensor connected to the monitoring unit based on an amount of Brillouin scattering indicated by the light information generated by each of the connected temperature sensors, an each monitoring unit generates a trip signal when a determined temperature value exceeds a running average by more than a threshold amount.

First claim

What is claimed:

1. A temperature change detection apparatus for monitoring temperature change in various portions of a first space comprising:
a trip logic unit configured to execute a trip operation based on receipt of a trip signal at the trip logic unit;
a plurality of temperature sensors being configured such that, for each of the plurality of temperature sensors, the temperature sensor includes an optical fiber cable that includes a sensing portion and the temperature sensor is configured to generate light information indicating an amount of Brillouin scattering that occurs within the sensing portion;
a plurality of monitoring units configured such that, for each one of the plurality of monitoring units, the monitoring unit is,
connected to temperature sensors from among the plurality of temperature sensors,
configured to, for each of the temperature sensors to which the monitoring unit is connected,
determine a temperature value corresponding to the connected temperature sensor based on an amount of Brillouin scattering indicated by the light information generated by the connected temperature sensor, the determined temperature value being indicative of a temperature at a location of the sensing portion of the connected temperature sensor, and
generate a comparison result based on the determined temperature value and a running average value, and

configured to generate the trip signal when at least one of the generated comparison results exceeds a threshold value,
wherein a first optical fiber cable includes a large fiber section and a small fiber section, the first optical fiber cable being the optical fiber cable included in a temperature sensor from among the plurality of temperature sensors, a cross-sectional diameter of the small fiber section being smaller than that of the large fiber section, the small fiber section corresponding to the sensing portion of the first optical fiber cable, the large fiber section corresponding to portions of the first optical fiber cable other than the sensing portion of the first optical fiber cable, and
wherein the large fiber section includes a first core and the small fiber section includes a second core, a radius of the first core being larger than a radius of the second core.

2. The temperature change detection apparatus of claim 1 , wherein the plurality of temperature sensors and the plurality of monitoring units are divided into a plurality of safety divisions such that each safety division includes a different one of the plurality of monitoring units and a different group of temperature sensors from among the plurality of temperature sensors.

3. The temperature change detection apparatus of claim 2 , wherein the trip logic unit is configured such that the trip logic unit executes the trip operation when a total number of trip signals received from the monitoring units of the plurality of safety divisions exceeds a trip threshold value.

4. The temperature change detection apparatus of claim 2 , wherein for each of the safety divisions, the group of temperature sensors included in the safety division are located, respectively, in a plurality of monitoring areas, the plurality of monitoring areas being located in spatially different areas of the first space.

5. The temperature change detection apparatus of claim 4 wherein, the plurality of temperature sensors are arranged such that, for each of the plurality of monitoring areas, the monitoring area includes at least one temperature sensor from each of the groups of temperature sensors.

6. The temperature change detection apparatus of claim 1 , wherein a first sensing portion includes a plurality of protrusions, the first sensing portion is the sensing portion of included in the optical fiber cable that is included in a temperature sensor from among the plurality of temperature sensors, the plurality of protrusions extend outwards from the optical fiber cable in which the first sensing portion is included, and the plurality of protrusions are configured to increase an amount of ambient heat delivered from a monitoring area in which the first sensing portion is located to the first sensing portion.

7. A nuclear plant system comprising:
a turbine building including one or more turbines configured to generate power from steam produced by a boiling water reactor (BWR); and
the temperature change detection apparatus of claim 1 ,
wherein
the first space is the turbine building,
the sensing portions of the plurality of temperature sensors are located in a plurality of monitoring areas, the plurality of monitoring areas being spatially distributed in different locations throughout the turbine building, and
the trip operation includes closing one or more valves.

8. The nuclear plant system of claim 7 , wherein the trip operation includes closing a main steam isolation valve (MSIV) of the turbine building.

9. The nuclear plant system of claim 7 , wherein the plurality of temperature sensors and the plurality of monitoring units are divided into a plurality of safety divisions such that each safety division includes a different one of the plurality of monitoring units and a different group of temperature sensors from among the plurality of temperature sensors.

10. The nuclear plant system of claim 9 wherein the trip logic unit is configured such that the trip logic unit executes the trip operation when a total number of trip signals received from the monitoring units of the plurality of safety divisions exceeds a trip threshold value.

11. The nuclear plant system of claim 9 wherein, for each of the safety divisions, the group of temperature sensors included in the safety division are located, respectively, in the plurality of monitoring areas.

12. The nuclear plant system of claim 11 wherein, the plurality of temperature sensors are arranged such that, for each of the plurality of monitoring areas, the monitoring area includes at least one temperature sensor from each of the safety divisions.

13. The nuclear plant system of claim 7 wherein, the sensing portion included in the optical fiber cable included in at least one of the plurality of temperature sensors includes a plurality of protrusions that extend outwards from the optical fiber cable and are configured to increase an amount of ambient heat delivered from the monitoring area in which the sensing portion is located to the sensing portion.

14. The plant system of claim 7 , wherein,
the turbine building includes at least one ventilation conduit configured to carry at least one of air and other gases into or out of the turbine building, and
the sensing portion included in the optical fiber cable included in at least one of the plurality of temperature sensors is located on an interior or exterior surface of the ventilation conduit.

Assignees

• Loewen Eric P
• Dooies Brett J
• Strege Seth Ryan Paul
• Oneill Nicholas Francis
• Ge Hitachi Nuclear Energy Americas Llc

Inventors

• Loewen Eric P
• Dooies Brett J
• Strege Seth Ryan Paul
• O'Neill Nicholas Francis

Classifications

• G01K1/026

  arrangements for monitoring a plurality of temperatures, e.g. by multiplexing · CPC title

• Y02E30/40

  Cross-Sectional Technologies · mapped topic

• G01K11/32 Primary

  using changes in transmittance, scattering or luminescence in optical fibres · CPC title

• G01K2011/322

  Physics · mapped topic

• G21D3/04

  Safety arrangements (emergency protection of reactor G21C9/00) · CPC title