JPS6312278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traveling neutron flux calibration device used to calibrate the sensitivity of a detector for measuring reactor power in a nuclear power plant, and particularly relates to a recording paper position adjustment method of the recorder. This invention relates to an improved traveling neutron flux calibration device.

The reactor output during operation of a nuclear power plant, for example a BWR type nuclear power plant, is measured by a number of local power range monitor (hereinafter abbreviated as LPRM) detectors fixedly placed within the reactor. for example,
A 1.1 million kilowatt class BWR nuclear power plant uses over 40 LPRM detector assemblies with built-in LPRM detectors located at four locations along the axis of the reactor.
These LPRM detectors have variations in performance between each other and sensitivity deterioration due to neutron irradiation.
It is necessary to periodically calibrate and use these outputs. Calibration is performed by inserting a common detector into the guide tube provided in each LPRM detector assembly, and
This is done by measuring the neutron flux at the location of the LPRM detector and comparing it with each other. A traveling neutron flux calibration device (hereinafter abbreviated as TIP) uses the common detector to measure the neutron flux distribution in the reactor for calibrating the LPRM detector.

TIP records the neutron flux distribution measurement results on a recorder, but the recording paper must be changed every time a measurement is made in each guide tube, and the position of a new recording paper must be adjusted when it is fixed on the recorder. .

The configuration of the conventional TIP and the recording paper position adjustment method will be explained below with reference to FIGS. 1, 2, and 3. Figure 1 is a diagram showing the configuration of a conventional TIP.
A TIP detector 3 that runs through a guide tube 11 provided inside the detector assembly, a selection mechanism 7 that switches between up to 10 guide tubes, a drive mechanism 8 that inserts and pulls out the TIP detector, and a selection mechanism 7. a drive control circuit 5 that controls the drive mechanism 8; a level conversion circuit 6 that converts the level of the position signal and measurement output of the TIP detector; a control device 4 that includes the drive control circuit 5 and the level conversion circuit 6;
A switch 9 that switches the output of the control device of each channel, and an X-Y that records the in-core neutron flux distribution measured by the TIP detector with the detector position in the X-axis direction and the neutron flux level in the Y-axis direction. It consists of a recorder 10.

FIGS. 2 and 3 show the recording paper position adjustment method of the conventional TIP described above. The in-core neutron flux distribution is recorded on the recording paper when the TIP detector 3 is pulled out from the reactor top 50 (the top of the reactor core 2 in the reactor 1) to the reactor bottom 51 (the bottom of the reactor core 2). The conventional recording paper position adjustment method is
As shown in FIG. 2, the TIP detector 3 is first inserted in step 100 and stopped at the standby position 52 (FIG. 1) (step 101). Since the standby position 52 is outside the reactor and the neutron flux level is 0, as shown in Figure 3,
- Align the pen P2 of the Y recorder with the position P1 on the scale of the recording paper 13, which is [reactor bottom position, neutron flux level 0], as indicated by arrow A (step 102).
Next, insert TIP detector 3 again (step
103) and is stopped at the hearth bottom position 51 (FIG. 1) (step 104). Since the neutron flux level is not 0 at the bottom position 51, leave the Y-axis direction of the recording paper 13 at P2, and set the [bottom position, neutron flux level 0] coordinate of the recording paper scale to the pen's X coordinate position P3. Move in the X-axis direction as shown by arrow B so that P2 comes (step 105). Now the recording paper scale [furnace bottom position,
Neutron flux level 0] coordinate position is determined. Further, in step 106, the TIP detector 3 is inserted, and in step 107, it is stopped at the furnace top position 50. By aligning the X coordinate position P5 of the pen with the position P4, where the X coordinate of the recording paper scale is the furnace top position (step 108), the recording paper position adjustment is completed.

The above is the conventional TIP recording paper position adjustment method, but it has the following drawbacks.

First, it takes time to adjust the position of the recording paper once, and it places a heavy burden on the operator.
It takes about two and a half minutes for the TIP detector to reach the furnace top position 50 from the standby position 52, and the operator is restrained during that time.When measurements are taken using all 40 guide tubes, the work required to adjust the recording paper position is This places a considerable burden on operators.

Second, there is a problem with the accuracy of recording paper position adjustment.
To adjust the position of the recording paper, as described above, in order to position one point on the recording paper, it is necessary to move the recording paper alternately in the X direction and the Y direction. In addition, the time required for the TIP detector to travel between the standby position 52, the furnace bottom position 51, and the furnace top position 50 is 1 minute to 1 and a half minutes, and the recording paper position is adjusted in stages at each position. As the operator gets used to the system, there is a risk that the operator will make an adjustment error, and the accuracy of neutron flux distribution recording will deteriorate.

Thirdly, the measurement time becomes longer. The TIP detector is stopped at standby, the bottom of the furnace, and the top of the furnace, and the recording paper position is adjusted, which increases the time required for one measurement.

It is an object of the present invention to provide a TIP that eliminates the drawbacks of the prior art described above, allows highly accurate recording sheet position adjustment in a short time, and reduces the burden on the operator.

The present invention applies a reference signal for adjusting the recording paper position to the X-Y recorder through a switch operation and a built-in program, and when the TIP detector position is outside the neutron flux distribution recording range, the position of the TIP detector is adjusted. This allows the recording paper position to be adjusted without any hassle.

Hereinafter, the present invention will be explained in detail with reference to Examples.
FIG. 4 is a diagram showing an embodiment of the present invention, in which the TIP detector 3, selection mechanism 7, and drive mechanism 8 in FIG. It is composed of a controller 16, a recorder operation console 15, a switching circuit 17, and an XY recorder 10. The control device 4 is composed of a sub-controller 14 and a level conversion circuit 6, and the sub-controller 14 is a conventional TIP that processes the selection mechanism and drive mechanism control functions that were processed by hardware circuits using a built-in software program. It is.

FIG. 5 is a diagram showing the console 15 and common controller 16 of FIG. 4 in more detail, FIG. 6 is a flowchart of these operations, and FIG. 7 is an explanatory diagram of the recording paper position adjustment method of the present invention.

When adjusting the recording paper position, the operator first sets the X-Y recorder calibration switch 18 on the console 15 to bottom 0 (FIG. 6, step 200). The program built into the common controller 16 takes in this set value via the digital input device 19 and determines the switch position (step 201).
In this case, since the bottom of the hearth is 0, proceed to step 202.
A bottom position signal as an X-axis signal and a neutron flux level 0 signal as a Y-axis signal are output from the analog output device 20 to the X-Y recorder 10. The operator is X-Y
At pen position P2 of the recorder 10, the (X, Y) coordinates of the recording paper scale are [reactor bottom position, neutron flux level 0]
Position P1 is aligned as shown by arrow A in FIG.

Next, the operator turns on the X-Y recorder calibration switch 18.
is set to 0 at the top of the furnace (step 200). The program built into the common controller takes in this set value via the digital input device 19 and determines the switch position (step 201). In this case, since the furnace top is 0, the process proceeds to step 203, where the analog output device 20 outputs a furnace top position signal as the X-axis signal and a neutron flux level 0 signal as the Y-axis signal to the X-Y recorder 10. The operator uses an X-Y recorder 10
At pen position P4, the (X, Y) coordinates of the recording paper scale are [furnace top position, neutron flux level 0].
Align P3 as shown by arrow B in Figure 7.

As described above, the recording paper position can be adjusted by switch operation and a built-in program. This recording paper position adjustment can be performed quickly regardless of the position of the TIP detector, except when the TIP detector is located in the core where neutron flux distribution is measured, and the recording paper can be adjusted simultaneously in the X and Y directions. High accuracy is achieved by moving and adjusting.

Note that the output from the analog output device 20 of the common controller 16 is in addition to the furnace bottom 0 and the furnace top 0.
Various types are possible, such as [furnace bottom position, neutron flux level output 125], [furnace top position, neutron flux level output 125] (these are the upper limit positions of the recording paper). If the position of the pen of the X-Y recorder and the scale of the recording paper do not match with respect to these outputs, it can be easily discovered that the input sensitivity of the X-Y recorder has changed.

As is clear from the above description, according to the present invention, the built-in program allows the chart paper position to be easily adjusted while the TIP detector is outside the reactor core, reducing the time for chart paper position adjustment and reducing the operator's burden. It is possible to reduce the burden and improve position adjustment accuracy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration example of a conventional TIP, FIGS. 2 and 3 are diagrams showing a recording paper position adjustment method of a conventional TIP, FIG. 4 is a diagram showing an embodiment of the present invention, and FIG. The figure is a detailed view of the console and common controller of FIG. 4, and FIGS. 6 and 7 are diagrams showing a recording paper position adjustment method according to the present invention. 1... Nuclear reactor, 2... Core, 3... TIP detector, 10... X-Y recorder, 14... Sub controller, 15... Console, 16... Common controller, 18... Calibration switch, 19...digital input device, 20...analog output device.

Claims (1)

[Claims] 1. A calibration detector that is driven to move in the core axial direction within a plurality of guide tubes provided in the reactor to calibrate the output measurement detector, and a calibration detector that is moved from the bottom of the reactor to the reactor core. a drive means for driving to the top; a selection means for selecting whether or not the calibration detector is inserted into the guide tube; a drive control means for controlling the drive means and the selection means; and a detection value of the calibration detector. a recorder for recording, a controller for controlling the recorder, and a console for operating the recorder having a calibration switch that applies the bottom position and the top position of the nuclear reactor to the controller as set values; A traveling neutron flux calibration device characterized in that the controller calculates a furnace bottom position signal and a furnace top position signal based on the set value from the calibration switch and aligns the recording paper of the recorder.