SELF-POWERED IN-CORE DETECTOR ARRANGEMENT FOR MEASURING FLUX IN A NUCLEAR REACTOR CORE

• US 20200135351A1
• Filed: 10/29/2018
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Framatome Inc. (Government of France)
• Original Assignee: Framatome Inc. (Government of France)
• Inventors: Johnson, Ian McKeag
• Granted Patent: US 11,227,697 B2
• Time in Patent Office: Days
• CPC Class Codes: G01T 3/006 using self-powered detectors (for neutrons as well as for Y- or X-rays) , e.g. using Compton-effect (Compton diodes) or photo-emission or a (n,B) nuclear reaction photovoltaic semiconductors H01L31/00; photo-tubes H01J40/00; thermionic generators H01J45/00; radioisotopic generators G21H1/00, e.g. G21H1/02, G21H1/04
• CPC Class Codes: G21C 17/044 Detectors and metering devices for the detection of fission products
• CPC Class Codes: G21C 17/108 Measuring reactor flux
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

A detector assembly for measuring flux in a nuclear reactor core includes a plurality of self-powered in-core detector arrangements each for measuring flux at a different one of a plurality of axial locations in the nuclear reactor core, and an assembly connector configured to be connected to a power plant connector. The assembly connector includes a plurality flux signal terminals each connected to one of self-powered in-core detector arrangements. At least one of the self-powered in-core detector arrangements comprises a set of at least two self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core. Each of the at least two self-powered in-core detectors includes a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line. The flux signal output lines of the at least two self-powered in-core detectors are joined together.

Claims

1. A detector assembly for measuring flux in a nuclear reactor core comprising

a plurality of self-powered in-core detector arrangements each for measuring flux at a different one of a plurality of axial locations in the nuclear reactor core;

and

an assembly connector configured to be connected to a power plant connector, the assembly connector comprising a plurality flux signal terminals each connected to one of self-powered in-core detector arrangements,

at least one of the self-powered in-core detector arrangements comprising a set of at least two self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core,

each of the at least two self-powered in-core detectors including a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line, the flux signal output lines of the at least two self-powered in-core detectors being joined together.

2. The detector assembly as recited in claim 1 wherein the joined flux signal output lines are connected to a same one of the flux signal terminals of the assembly connector.

3. The detector assembly as recited in claim 1 wherein the detector material section is a same detector material for all of the at least two self-powered in-core detectors.

4. The detector assembly as recited in claim 2 wherein the detector material section is a same size and shape for all of the at least two self-powered in-core detectors.

5. The detector assembly as recited in claim 1 wherein the at least one of the self-powered in-core detector arrangements comprising a set of at least two self-powered in-core detectors comprise:

a first self-powered in-core detector arrangement comprising a set of first self-powered in-core detectors for measuring flux at a first axial location in the nuclear reactor core, flux signal output lines of the first self-powered detectors being joined together to provide a first combined flux signal for identifying the flux of the nuclear reactor core at the first axial location; and

a second self-powered in-core detector arrangement comprising a set of second self-powered in-core detectors for measuring flux at a second axial location in the nuclear reactor core axially offset from the first axial location, flux signal output lines of the second self-powered detectors being joined together to provide a second combined flux signal for identifying the flux of the nuclear reactor core at the second axial location.

6. The detector assembly as recited in claim 5 wherein each of the first self-powered in-core detectors includes a lead wire extending from the detector material section and transmitting a flux signal to one of the flux signal output lines,

each of the first self-powered in-core detectors including a background wire spaced from the detector material section by the insulator and transmitting a background signal to a first background signal output line,

each of the second self-powered in-core detectors includes a lead wire extending from the detector material section and transmitting a flux signal to one of the flux signal output lines,

each of the second self-powered in-core detectors including a background wire spaced from the detector material section by the insulator and transmitting a background signal to a second background signal output line.

7. The detector assembly as recited in claim 6 wherein the first background signal output lines of the first self-powered detectors are joined together to provide a first combined background signal for the set of first self-powered in-core detectors and the second background signal output lines of the second self-powered detectors are joined together to provide a second combined background signal for the set of second self-powered in-core detectors

8. The detector assembly as recited in claim 7 wherein the connector includes a first background signal terminal for outputting the first combined background signal and a second background signal terminal for outputting the second combined background signal.

9. The detector assembly as recited in claim 8 wherein the connector includes two thermocouple terminals and a collector terminal electrically connected to the sheaths.

10. The detector assembly as recited in claim 5 further comprising:

a set of third self-powered in-core detectors at a third axial location, third flux signal output lines of the third self-powered detectors being joined together to provide a third combined flux signal for identifying the flux of the nuclear reactor core at the third axial location; and

a set of fourth self-powered in-core detectors at a fourth axial location axially offset from the third axial location, fourth flux signal output lines of the fourth self-powered detectors being joined together to provide a fourth combined flux signal for identifying the flux of the nuclear reactor core at the fourth axial location,

each of the third self-powered in-core detectors and the fourth self-powered in-core detectors including a respective sheath, a detector material section inside the sheath and an insulator between the sheath and the detector material section.

11. A method of providing a detector assembly for measuring flux in a nuclear reactor core comprising:

arranging a plurality of self-powered in-core detector arrangements in the nuclear reactor core each for measuring flux at a different one of a plurality of axial locations in the nuclear reactor core; and

connecting an assembly connector to the self-powered in-core detector arrangements, the assembly connector comprising a plurality flux signal terminals each connected to one of self-powered in-core detector arrangements, the assembly connector configured to be connected to a power plant connector,

at least one of the self-powered in-core detector arrangements comprising a set of at least two self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core,

each of the at least two self-powered in-core detectors including a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line, the flux signal output lines of the at least two self-powered in-core detectors being joined together.

12. The method as recited in claim 11 wherein the joined flux signal output lines are connected to a same one of the flux signal terminals of the assembly connector.

13. The method as recited in claim 11 wherein the detector material section is a same detector material for all of the at least two self-powered in-core detectors.

14. The method as recited in claim 13 wherein the detector material section is a same size and shape for all of the at least two self-powered in-core detectors.

15. The method as recited in claim 14 wherein the arranging of the plurality of self-powered in-core detector arrangements in the nuclear reactor core comprises:

arranging a first self-powered in-core detector arrangement in the nuclear reactor core at a first axial location, the first self-powered in-core detector arrangement comprising a set of first self-powered in-core detectors for measuring flux at the first axial location in the nuclear reactor core, flux signal output lines of the first self-powered detectors being joined together to provide a first combined flux signal for identifying the flux of the nuclear reactor core at the first axial location; and

arranging a second self-powered in-core detector arrangement in the nuclear reactor core at a second axial location axially offset from the first axial location, the first self-powered in-core detector arrangement comprising a set of second self-powered in-core detectors for measuring flux at the second axial location, flux signal output lines of the second self-powered detectors being joined together to provide a second combined flux signal for identifying the flux of the nuclear reactor core at the second axial location.

16. The method as recited in claim 15 wherein each of the first self-powered in-core detectors includes a lead wire extending from the detector material section and transmitting a flux signal to one of the flux signal output lines,

each of the first self-powered in-core detectors including a background wire spaced from the detector material section by the insulator and transmitting a background signal to a first background signal output line,

each of the second self-powered in-core detectors includes a lead wire extending from the detector material section and transmitting a flux signal to one of the flux signal output lines,

each of the second self-powered in-core detectors including a background wire spaced from the detector material section by the insulator and transmitting a background signal to a second background signal output line,

the first background signal output lines of the first self-powered detectors are joined together to provide a first combined background signal for the set of first self-powered in-core detectors and the second background signal output lines of the second self-powered detectors are joined together to provide a second combined background signal for the set of second self-powered in-core detectors

17. The method as recited in claim 16 wherein the connector includes a first background signal terminal for outputting the first combined background signal and a second background signal terminal for outputting the second combined background signal.

18. The method as recited in claim 17 wherein the connector includes two thermocouple terminals and a collector terminal electrically connected to the sheaths.

19. A method of replacing a first detector assembly for measuring flux in a nuclear reactor core with a second detector assembly for measuring flux in a nuclear reactor core, the method comprising:

uninstalling the first detector assembly from the nuclear reactor core, the first detector assembly comprising;

a plurality of first self-powered in-core detector arrangements each for measuring flux at a different one of a plurality of axial locations in the nuclear reactor core; and

a first assembly connector configured to be connected to a power plant connector, the first assembly connector comprising a plurality first flux signal terminals each connected to one of first self-powered in-core detector arrangements,

at least one of the first self-powered in-core detector arrangements comprising a set of at least two first self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core,

each of the at least two first self-powered in-core detectors including a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line, the flux signal output lines of the at least two first self-powered in-core detectors being joined together,

the uninstalling of the first detector assembly from the nuclear reactor core including disconnecting the first assembly connector from a power plant electrical connector;

installing the second detector assembly in the nuclear reactor core in place of the first detector assembly, the second detector assembly comprising;

a plurality of second self-powered in-core detector arrangements each for measuring flux at a different one of a plurality of axial locations in the nuclear reactor core; and

a second assembly connector configured to be connected to a power plant connector, the second assembly connector comprising a plurality second flux signal terminals each connected to one of second self-powered in-core detector arrangements,

at least one of the second self-powered in-core detector arrangements comprising a set of at least two second self-powered in-core detectors for measuring flux at a same one of the axial locations in the nuclear reactor core,

each of the at least two second self-powered in-core detectors including a sheath, a detector material section inside the sheath, an insulator between the sheath and the detector material, and a flux signal output line, the flux signal output lines of the at least two second self-powered in-core detectors being joined together,

the installing of the second detector assembly in the nuclear reactor core including connecting the second assembly connector to the power plant electrical connector.

20. The method as recited in claim 19 wherein the detector material sections of the first self-powered in-core detectors are formed of a first material and the detector material sections of the second self-powered in-core detectors are formed of a second material different from the first material.

21. The method as recited in claim 19 wherein the set of the first self-powered in-core detectors has a first number of detectors and the set of the second self-powered in-core detectors has a second number of detectors different from the first number.

22. The method as recited in claim 19 wherein the first assembly connector and the second assembly connector have a same number of terminals.