JPS6214092A - Measuring device for output region of nuclear reactor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] Mizumoto Ill relates to a power range [i+ measuring device] of, for example, a boiling water nuclear reactor, and in particular to a power range measuring device that makes it possible to efficiently calibrate a detector. One season.

[Technical background of the invention]

Generally, boiling water reactors (BWRs) are equipped with neutron instrumentation within the reactor core to measure power distribution. Since the reactor output ranges over a wide range from the neutron source region to the power operation region, this neutron instrumentation is divided into a startup region system, an intermediate region system, and a power region system, and four measurements are performed for each predetermined power range. Neutron instrumentation of the startup region system (Sr(
M) and intermediate region system neutron instrumentation (IRM), one circular passage and one detector each are installed in a predetermined number of guide tubes so that they can be raised and lowered. It is inserted into the reactor core, and after reaching the rated output, it is pulled out of the reactor core.

On the other hand, the power range neutron instrumentation (hereinafter abbreviated as LPPM) is used to detect the power in the region near the rated power. For example, as shown in FIG. A support tube (hereinafter L PRM
A detector support tube (hereinafter referred to as a detector support tube) 3 is provided, and a plurality of local power range detectors (hereinafter referred to as LPRM detectors) 4 are provided above and below at intervals. This LPRM detector 4
is constantly exposed to high levels of neutron flux, which changes its sensitivity. Therefore, in order to accurately measure the neutron flux distribution within the nuclear reactor over a long period of time, it is necessary to calibrate it at appropriate intervals.

For this calibration, a mobile neutral predictor illumination device (hereinafter referred to as TIP) is used.
) 5 is provided. That is, the TIP 5 is provided within the dry duplex 2 so as to be movable up and down via the TIP guide tube 6, and is driven four times downward by the TIP drive mechanism 8 via the operation wire V7. Calibration is performed by moving this TIP 5 up and down along the LPRM detector 4, and it is pulled out to its superior index box 9, and then guided by the indexing device to the LPRM detector 4 with the power of calibration η, and thereafter the same operation is performed.

Note that 10 is a reactor pressure vessel, 11 is a core support plate, and 12 is a reactor pressure vessel.
indicates the upper grid plate.

[Problems with dorsal technique]

In the conventional LPPM, the LPRM detector 4 is fixed inside the dry tube 2, so when calibrating the LPPM, the T
The IP has to repeatedly move back and forth from the lower end of the core to the upper end of the core, and the scanning distance of the TIP becomes large, requiring, for example, two or more distances, resulting in relatively poor work efficiency.

[Purpose of the invention]

The present invention was made in view of these circumstances, and the TI
It is an object of the present invention to provide a power range measurement device for a nuclear reactor that can efficiently calibrate an LPRM detector using TIP by reducing the scanning distance of P.

[Summary of the invention]

In order to achieve the above object, the present invention includes a plurality of LPPM detection units installed vertically and at intervals in a vertical dry tube of a nuclear reactor core via support tubes. In the power range measurement bag 2 for a nuclear reactor, which has a TIP that can be raised and lowered by
It is characterized by the provision of a driving vJ mechanism that raises and lowers the support tube of the M detector while maintaining the vertical interval of the LPPM detector.

(Embodiment of the Invention) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 shows a schematic configuration of a nuclear reactor power range measuring device according to this embodiment.

In the figure, 13 is a reactor pressure vessel in a pressure vessel pedestal 13a, 14 is a core support plate, 15 is an upper lattice plate, 1
6 does not show the reactor core. A vertical dry tube 17 is provided within the reactor core 16, and an LPPM detector support tube 18 is provided within the dry tube 17 so as to be movable up and down. L
Inside the PRM detector support tube 18 is an LPPM detection P! i19
There are multiple spaces above and below. Then, the LPRM detector support tube 18 is connected to the LPRM detector 1 by the drive mechanism 20.
It is possible to go up and down while maintaining the vertical distance of 9.

A drive mechanism housing space 21 is formed in the lower portion of the nuclear reactor core 16 of the dry duplex 17, and a drive mechanism 20 including a motor, gears, etc. is housed in this drive mechanism housing space 21. At least the LPRM detectors 19 at the upper and lower ends
The LPPM detector support tube 18 can be moved up and down by the distance between.

TIP 22 for calibration is installed inside the dry duplex 17.
It is provided so that it can be raised and lowered via a guide tube 23, and is raised and lowered 8 by a TIP drive mechanism 25 via an operating wire 24. In addition, 26 is an index box, and TIP22 should be calibrated by the indexing device built into it.
It is for guiding to the M detector 19.

Next, the calibration action will be explained with reference to FIG.

For example, as shown in FIG. 2(A), while holding the LPRM detector 19 in its normal position, push the TIP 22 up to the height of the lowest LPPM detector 19, and PRM detection Detection 41 Next, as shown in Fig. 2 (B), pull out the TIP 22, and then, as shown in Fig. 2 (C)
13 and as shown in FIG. 2(D), the reactor core 16
While scanning the neutron flux inside, the LPPM detector support tube 18 is moved vertically and returned to its normal position as shown in FIG. 2(E).

By such an operation, the axial neutron flux distribution in the reactor core can be measured by each LPRM detector 19, and at the same time, the sensitivity of the vertically adjacent LPRM detectors 19 can be calibrated to each other in phase n.

Therefore, the lowest LPP by TIP22 performed earlier
From the results of the calibration of the M detector 19, each LP adjacent to the upper and lower
Absolute calibration of the RM detector 19 and measurement of the axial center distribution of the nuclear reactor core 16 can be performed.

J3, when performing LPPM calibration of the entire core of an actual reactor, all LPPM in the reactor core 16 should be calibrated in advance.
The PM detector support tube 18 is simultaneously moved up and down to scan the neutron flux distribution, and the calibration of the lowest stage LPPM detector 19 by TIP is performed separately.

According to such a configuration, the TIP 22 is connected to the bottom 1ρR.
Insert it up to the quality position of the M detector 19, and then
Since the flow only needs to be calibrated for the PRM detector 19, the scanning time is reduced to 1/4 to 1/2 compared to the conventional output area measuring device 2.
Since the core neutron flux distribution is simultaneously scanned by each LPPM, there are advantages such as being less affected by temporal changes in the core output.

〔Effect of the invention〕

As described above, according to the power range measurement device for a nuclear reactor according to the present invention, a drive mechanism is provided to lower the support tube of the local power range detector 4 times while maintaining the vertical interval of the power range detector, Since it is only necessary to insert the moving neutral predictor 811 up to the position of the lowest local output area detector and calibrate the lowest local output area detector, the mobile neutral predictive measurement is possible. The scanning distance of the device can be reduced, and its moving neutral predictor i1! IP! It becomes possible to improve the efficiency of the calibration of the local output region detector by i.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts showing one embodiment of the present invention, FIGS. 2(A) to (E) are explanatory views showing the operation, and FIG. 3 is a sectional view showing a conventional example. 16... Nuclear reactor core, 17... Dry tube, 1
8... Support tube, 19... Peripheral output area detector, 2o
... Drive mechanism, 22 ... Moving neutral predictive measuring instrument, 23
...Guiding tube. Representative Patent Attorney Kensuke Chika Figure 1

Claims (1)

[Claims] A plurality of local power range detectors are provided at intervals above and below via support tubes in the vertical dry tube of the nuclear reactor core, and moving neutrons are provided in the dry tube so as to be movable up and down via guide tubes. A power range measuring device for a nuclear reactor having a measuring instrument, characterized in that a drive mechanism is provided for raising and lowering the support tube of the local power range detector while maintaining the vertical interval of the power range detector. Furnace power range measuring device.