CN113628772A

CN113628772A - Nuclear instrument system

Info

Publication number: CN113628772A
Application number: CN202010377126.6A
Authority: CN
Inventors: 邳立鹏; 孙娜; 张�杰; 张瑞萍; 吕爱国
Original assignee: Hualong International Nuclear Power Technology Co Ltd
Current assignee: Hualong International Nuclear Power Technology Co Ltd
Priority date: 2020-05-07
Filing date: 2020-05-07
Publication date: 2021-11-09

Abstract

The present invention provides a nuclear instrumentation system, the system comprising: a neutron detector; the neutron detector comprises at least three detector combinations, the detector combinations comprising: the source range detector comprises a first end and a second end which are relatively far away, the first working range detector is connected with the first end of the source range detector, and the second working range detector is connected with the second end of the source range detector. The invention can improve the reliability of the nuclear instrument system.

Description

Nuclear instrument system

Technical Field

The invention relates to the technical field of nuclear power, in particular to a nuclear instrument system.

Background

In nuclear power plants, nuclear instrumentation systems are used primarily to continuously monitor the power of the reactor, changes in power levels, and the axial power distribution of the reactor. Neutron fluence rate measurements are made in nuclear instrumentation systems by detectors placed in the reactor pressure vessel. The existing detector comprises 8 sub-detectors, and the 8 sub-detectors are respectively: 2 source range detectors, 2 middle range detectors and 4 power range detectors, the existing detectors easily cause problems of reactor mis-shutdown and the like in the operation process, and the reliability of the nuclear instrument system is low.

Disclosure of Invention

The embodiment of the invention aims to provide a nuclear instrument system to solve the problem of low reliability of the nuclear instrument system.

In order to achieve the above object, an embodiment of the present invention provides a nuclear instrumentation system, including: a neutron detector; the neutron detector comprises at least three detector combinations, the detector combinations comprising: the source range detector comprises a first end and a second end which are relatively far away, the first working range detector is connected with the first end of the source range detector, and the second working range detector is connected with the second end of the source range detector.

Optionally, the number of the at least three detector combinations is four.

Optionally, the source range detector is disposed at a middle section of the active segment of the core.

Optionally, the distance from the center of the first working range detector to the bottom of the active core section is greater than the distance from the center of the first working range detector to the top of the active core section; the distance from the center of the second working range detector to the bottom of the active core section is smaller than the distance from the center of the second working range detector to the top of the active core section.

Optionally, the first working range detector is detachably connected to the first end of the source range detector, and the second working range detector is detachably connected to the second end of the source range detector.

Optionally, the range of the source range detector partially overlaps the range of the first operating range detector, and the range of the source range detector partially overlaps the range of the second operating range detector.

Optionally, the first working range detector and the second working range detector both include a fission chamber, and the source range detector includes a boron-coated proportional counter tube.

Optionally, the at least three detectors are uniformly combined and arranged in a biological shielding wall at the periphery of the reactor pressure vessel.

Optionally, the nuclear instrumentation system further includes at least three protection cabinets, the number of the at least three protection cabinets is consistent with that of the at least three detector combinations, one protection cabinet is connected to one detector combination, and a signal processor is arranged in the protection cabinet.

Optionally, the detector assembly is cylindrical in external shape.

One of the above technical solutions has the following advantages or beneficial effects:

in an embodiment of the present invention, a nuclear instrumentation system includes: a neutron detector; since the neutron detector includes at least three detector combinations, the detector combinations include: the source range detector comprises a first end and a second end which are relatively far away, the first working range detector is connected with the first end of the source range detector, and the second working range detector is connected with the second end of the source range detector. Compare among the prior art like this that nuclear instrumentation's detector includes 8 sub-detectors, and 8 sub-detectors are respectively: 2 source range detectors, 2 intermediate range detectors and 4 power range detectors; the embodiment of the invention can improve the reliability of a nuclear instrument system.

Drawings

FIG. 1 is a schematic diagram of a detector assembly provided by an embodiment of the present invention;

FIG. 2 is a diagram of an application scenario of a detector assembly according to an embodiment of the present invention;

FIG. 3 is a diagram of another application scenario of a detector assembly according to an embodiment of the present invention;

fig. 4 is a schematic diagram of a nuclear instrumentation system according to an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

A nuclear instrumentation system comprising: a neutron detector; the neutron detector includes at least three detector combinations, as shown in fig. 1, and an embodiment of the present invention provides a schematic diagram of a detector combination, as shown in fig. 1, including: the measuring device comprises a first working range detector 11, a source range detector 12 and a second working range detector 13, wherein the source range detector 12 comprises a first end and a second end which are relatively far away, the first working range detector 11 is connected with the first end of the source range detector 12, and the second working range detector 13 is connected with the second end of the source range detector 12.

In nuclear power plants, the nuclear instrumentation system is primarily used to continuously monitor the power of the reactor, the power level variations, and the reactor axial power distribution. Neutron fluence rate measurements are made in the nuclear instrumentation system by the detector assembly disposed in the reactor pressure vessel. In this embodiment of the present invention, the nuclear instrumentation system includes at least three detector combinations, and the number of the at least three detector combinations may be three, four, or five, which is not limited in this embodiment of the present invention.

The nuclear instrument system comprises at least three detector combinations, the nuclear instrument system comprises at least three detection channels, when one of the detector combinations is abnormal, or when one of the detector combinations is in the debugging, overhauling or testing period, the other at least two detector combinations can still normally measure the neutron fluence rate, the measurement accuracy is higher, the reactor is not easy to be stopped by mistake, and the redundancy and the reliability of the nuclear instrument system are higher.

As shown in fig. 1, the detector assembly includes: the detector combination comprises three measurement sensitive sections, wherein a source range channel comprises one sensitive section, and a working range channel comprises two sensitive sections. The working range detector and the source range detector are combined together, so that the detection position occupied by a reactor workshop is reduced, the occupation of the space of the reactor workshop is reduced, and supporting civil engineering facilities are reduced.

In actual use, the internal structures of the first operating range detector 11 and the second operating range detector 13 can be identical, and the first operating range detector 11 and the second operating range detector 13 measure the neutron fluence rate of the active core section at different positions.

As an alternative embodiment, the number of the at least three detector combinations is four.

In this embodiment, when the nuclear instrumentation system is in normal operation, the nuclear instrumentation system may take two measurement results from the four detector combinations, and if one of the detector combinations fails in measurement at this time and an abnormal signal is falsely triggered, a reactor shutdown error is not caused. In addition, when one of the detector combinations is in a maintenance or test period, the nuclear instrument system can take two of the measurement results from the three detector combinations, and can also meet a single failure criterion during the maintenance and test periods, thereby improving the accuracy of neutron fluence rate measurement and enhancing the reliability of signal monitoring. The quadruple redundant channel improves the reliability of the nuclear instrument system and simultaneously ensures the economical efficiency of the nuclear power station operation.

As an alternative implementation, as shown in fig. 2, the embodiment of the present invention provides an application scenario diagram of a detector combination, and the source range detector 12 is disposed at the middle section d of the active segment of the core.

In this embodiment, one sensitive segment in the source-span channel is axially disposed at the core active segment midplane d. The arrangement principle is as follows: when the first cycle of the reactor of the nuclear power plant is finished, the primary neutron source is moved out of the reactor core, the subsequent cycle only comprises the secondary neutron source, and the optimal position of the axial arrangement of the source range detector 12 is the middle section d of the active section of the reactor core, namely the middle plane d of the active section of the reactor core. A primary neutron source may also be disposed at the midplane d of the active core section. Such an arrangement improves the accuracy of the source range detector 12 measurement.

As an alternative embodiment, as shown in fig. 2, the distance from the center of the first operating range detector 11 to the bottom a of the active core segment is greater than the distance from the center of the first operating range detector 11 to the top b of the active core segment; the distance from the center of the second working range detector 13 to the bottom a of the active core section is less than the distance from the center of the second working range detector 13 to the top b of the active core section.

In this embodiment, as shown in fig. 2, two sensitive segments of the operating range channel are axially arranged at the top 1/4 and the bottom 1/4 of the active core segment, as shown in fig. 2, c in fig. 2 marks the position of the top 1/4 of the active core segment, e in fig. 2 marks the position of the bottom 1/4 of the active core segment, and the first operating range detector 11 and the second operating range detector 13 are symmetrically arranged above and below the active core segment, so as to monitor the condition of axial power deviation; the effect of xenon oscillation on the core can also be monitored during accident conditions.

In an alternative embodiment, the first operating range detector 11 is detachably connected to a first end of the source range detector 12, and the second operating range detector 13 is detachably connected to a second end of the source range detector 12.

In this embodiment, the first working range detector 11 and the first end of the source range detector 12 may be detachably connected by a universal joint, when one of the first working range detector 11 and the source range detector 12 is out of order or the service life of the other one is expired, the other one can be detached and replaced, and the other one still remains to be used, so as to improve the economy of the detector combination; meanwhile, the single detector can be conveniently overhauled by detachable connection, and the convenience of combined use of the detectors is improved. The connection between the second operating range detector 13 and the second end of the source range detector 12 is similar.

In an alternative embodiment, the range of the source range detector 12 partially overlaps the range of the first operating range detector 11, and the range of the source range detector 12 partially overlaps the range of the second operating range detector 13.

The nuclear instrument system is designed with two range channels, namely a source range channel and a working range channel. The range of the source range detector 12 and the range of the first working range detector 11 are generally overlapped by at least two orders of magnitude, and similarly, the range of the source range detector 12 and the range of the second working range detector 13 are also generally overlapped by at least two orders of magnitude, so that the continuity of control and protection in the whole range of the reactor power is ensured, the readings between the source range channel and the working range channel are checked with each other, and the signals are interlocked with each other.

In an alternative embodiment, the first operating range detector 11 and the second operating range detector 13 each include a fission chamber, and the source range detector 12 includes a boron-coated proportional counter tube.

In this embodiment, the source range detector 12 adopts a boron-coated proportional counter tube, the first working range detector 11 and the second working range detector 13 adopt a fission chamber technology, and the fission chamber has a wider neutron measurement range, so that the measurement effect is improved, and the measurement requirement is better met. The two fission chambers in the detector combination can realize the measurement function of one compensation ionization chamber in six ionization chambers and a middle range in the power range in the prior art, and the detector combination has simpler structure and longer service life on the premise of ensuring the function and the safety requirement.

The source-scale channel provides reactor loading, shutdown and startup, and low power reactor status information to the plant operator and provides reactor shutdown protection. The working range channel provides reactor information under the working conditions of reactor shutdown, reactor startup, power operation and accident, provides control, alarm and corresponding signals for a rod control rod position system, a diversified protection system, a loosening component, a vibration monitoring system, a reactor core measuring system and other related systems and control rooms, provides signals with high neutron fluence rate and high fluence rate change rate for the reactor protection system, and triggers emergency reactor shutdown. The working range channel also has the function of monitoring the reactor core after an accident, and the channel is available within 72 hours after the accident.

As an optional embodiment, the at least three detector combinations are uniformly arranged in a biological shielding wall at the periphery of the reactor pressure vessel.

As shown in fig. 3, an application scenario diagram of a detector assembly according to another embodiment of the present invention is provided, and as shown in fig. 3,

reference numerals

1,2,3, and 4 in fig. 3 respectively represent four detector assemblies, and the four detector assemblies are respectively disposed at symmetric positions of 45 °, 135 °, 225 °, and 315 ° outside the reactor pressure vessel 5, so that accuracy of detection is improved. It should be noted that the at least three detector combinations are uniformly disposed in the biological shielding wall at the periphery of the reactor pressure vessel 5, and the at least three detector combinations may be disposed at other angles outside the reactor pressure vessel 5, which is not limited to this embodiment.

As an optional implementation manner, as shown in fig. 4, an embodiment of the present invention provides a schematic diagram of a nuclear instrumentation system, as shown in fig. 4, the nuclear instrumentation system further includes at least three protection cabinets, the number of the at least three protection cabinets is the same as that of the at least three detector combinations, one protection cabinet is connected to one detector combination, and a signal processor is disposed in the protection cabinet.

In this embodiment, the at least three protection cabinets are respectively disposed in different safety plants outside the containment of the nuclear power plant, and the signal processor is disposed in the protection cabinets, and is capable of adjusting and processing signals generated in the detector assembly and providing required data and standard signal interfaces for downstream. The protection rack will adjust and signal transmission after handling to the control cabinet, the control cabinet turns into the speaker sound signal with the count rate signal to for taking off part and vibration monitoring system provide neutron level and neutron noise signal.

The at least three protection cabinets are respectively and correspondingly independently powered by a plurality of power supplies, mutual interference is avoided, and the reliability of the nuclear instrument system is improved.

As an alternative embodiment, the external shape of the detector assembly is cylindrical.

For the size of the detector combination, by way of example, when the axial length of the active section of the core is 3600mm, in combination with practical application experience and scientific theory of nuclear power plants, the length of the first working range detector 11 and the length of the second working range detector 13 are set to be 1100mm, and the length of the source range detector is set to be 800 mm; the diameters of the bottom surfaces of the first working range detector 11, the source range detector 12 and the second working range detector 13 are set to be 200 mm. The detector assembly may be provided in other dimensions depending on the size of the core or the length of the active core segment, and this embodiment is not limited thereto.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A nuclear instrumentation system, comprising: a neutron detector; the neutron detector comprises at least three detector combinations, the detector combinations comprising: the source range detector comprises a first end and a second end which are relatively far away, the first working range detector is connected with the first end of the source range detector, and the second working range detector is connected with the second end of the source range detector.

2. The nuclear instrumentation system of claim 1, wherein the number of said at least three detector combinations is four.

3. The nuclear instrumentation system of claim 1, wherein said source range detector is disposed at a midsection of the active core segment.

4. The nuclear instrumentation system of claim 3, wherein the distance from the center of said first operating range detector to the bottom of said active core segment is greater than the distance from the center of said first operating range detector to the top of said active core segment; the distance from the center of the second working range detector to the bottom of the active core section is smaller than the distance from the center of the second working range detector to the top of the active core section.

5. The nuclear instrumentation system of claim 1, wherein said first operating range detector is removably coupled to a first end of said source range detector and said second operating range detector is removably coupled to a second end of said source range detector.

6. The nuclear instrumentation system of claim 1, wherein the source range detector has a range that partially overlaps the range of the first operating range detector and the source range detector has a range that partially overlaps the range of the second operating range detector.

7. The nuclear instrumentation system of claim 1, wherein said first operating range probe and said second operating range probe each include a fission chamber, and said source range probe includes a boron-coated proportional counter tube.

8. The nuclear instrumentation system of claim 1, wherein the at least three probe assemblies are uniformly disposed within a biological barrier surrounding the reactor pressure vessel.

9. The nuclear instrumentation system of claim 1, further comprising at least three protective cabinets in a number corresponding to the number of the at least three detector assemblies, wherein one protective cabinet is coupled to each of the detector assemblies, and wherein a signal processor is disposed in the protective cabinet.

10. The nuclear instrumentation system of claim 1, wherein an exterior shape of said probe assembly is cylindrical.