JPH0463359B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to improvements in nuclear reactor Traversing Incore Probe Monitor systems.

Technical background of the invention Generally, a nuclear power plant has 100 to 200
By installing several neutron flux detectors LPRM and monitoring the output of these neutron flux detectors LPRM with a reactor power system monitoring instrumentation system, the reactor output during reactor operation is ascertained. By the way, these neutron flux detectors LPRM have sensitivity variations and deterioration due to neutrons, so it is necessary to correct the detector output by adjusting the gain of the amplifier in the measurement system.

A movable in-core probe (hereinafter referred to as TIP) system is used to measure calibration data and neutron flux distribution in the core for the above correction purpose. Conventionally, this TIP system has a guide tube selection mechanism 3 on the reactor site side A that selects a plurality of guide tubes 2 led out from the reactor pressure vessel 1, as shown in FIG. , shield room 4...
and a TIP drive mechanism 5... which drives the TIP detector in the guide tube 2 to obtain an in-reactor neutron flux level signal, while the central control room side B has an output from the TIP drive mechanism 5... TIP board 7 with built-in TIP measurement system 6 for measuring the in-core neutron flux level signal
and a process computer 9 that controls the TIP panel 7 via a control line 8.
In the figure, 10 shows the input/output control line with the site side, C shows the bottom of the reactor core, D shows the top of the reactor core, and E shows the reactor fuel area.

By the way, in the above TIP system, the guide tube 2
The number of... varies depending on the size of the plant, but in the case of a boiling water nuclear power plant BWR, it is around 30 to 50, while a calibration scan usually requires 4 to 5 units.
Performed by TIP detector. However, since these TIP detectors have different sensitivities, the gains of the amplifiers of the TIP measurement system 6 need to be matched with high accuracy. A TIP scan initially scans all TIP detectors using a common guide tube. Then, the operator changes the feedback resistor 6b of the TIP amplifier 6a shown in FIG. 2 and sets the gain while recording with a recorder so that the outputs of all TIP detectors show the same instruction. There is. Note that during TIP scanning, the reactor output level is kept constant. In the figure, 11 is a high voltage power supply, 12 is
It is a TIP detector.

Problems with the Background Art The TIP system as described above has the following problems.

First, since the operator manually sets the gain of the amplifier 6a, the gain setting varies depending on the operator.

Bad gain setting.

If the gain setting is too high, the amplifier 6a of the TIP measurement system 6 will become saturated at a location where the power distribution in the core is high, making it impossible to obtain data.
Conversely, if the gain setting is too low, the accuracy of the data will deteriorate.

It takes time to set the gain.

Gain setting must be done carefully for the reasons mentioned above, which not only places a heavy psychological burden on the operator, but also requires a long setting time as the TIP common guide tube is often operated multiple times to ensure caution. Tend.

It is desirable for TIP scanning to be completed in a short time in terms of plant operation, and since maintenance may be performed on the TIP detector and the TIP equipment on the reactor site side A after the TIP scanning is completed, in order to reduce radiation exposure, the detector It was desired to minimize the amount of irradiation inside the reactor core.

Purpose of the Invention The present invention has been made in view of the above-mentioned circumstances, and it is possible to automatically and highly accurately set the gain of the amplifier in the TIP measurement system without any variation.
An object of the present invention is to provide a movable in-core probe monitoring system for a nuclear reactor that can prevent defective gain settings.

SUMMARY OF THE INVENTION The present invention has an amplifier whose gain can be set digitally, and allows gain setting of the amplifier by manually and automatically selecting gain setting data, and the gain setting of the amplifier is set at the top of the reactor core. The aim is to achieve the above objective by conducting the research based on the following.

Embodiment of the Invention Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 3 is a diagram showing a specific configuration of a TIP panel in a movable in-core probe monitoring system for a nuclear reactor. In addition, in the same figure, the first
The same parts as those in the figure and FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted. That is, TIP board 20
consists of TIP measurement systems 21... and a control system 22 that operates and controls these TIP measurement systems 21...
Each TIP measurement system 21 includes a high voltage power supply 211 that applies high voltage to the TIP detector 12, a TIP amplifier 212 whose gain can be adjusted digitally, and a manual gain setting switch 213 consisting of three to four digital switches. , automatic gain setting data memory 21
4, select either of these switches 213 and automatic gain setting data memory 214 and press TIP.
Selection circuit 21 that sets the gain of amplifier 212
5. The control system 22 includes a switch 221 for automatic/manual switching and an arithmetic control section 222.
It is equipped with This arithmetic control section 222 can be configured with either a microcomputer or hardware logic, and its function is to control the TIP amplifier 2.
12 gain settings, control of reactor site equipment for driving the TIP detector, monitoring the position of the TIP detector, and input/output processing of TIP data with the process computer 9. In addition, 23 is an automatic/manual switching signal, 24 is gain data for automatic, 25 is TIP data (neutron flux level signal), 26 is an input/output line with the process computer 9, 27 is a signal line from the field equipment side, 28 is the control line to the field equipment side. In addition, in the embodiment shown in FIG.
Although the TIP measurement system 21 has been shown, this TIP measurement system 21 can be added according to the number of TIP detectors 12, and if the necessary wiring is done in the TIP board 20 in advance, the TIP measurement system 21 can be added according to the number of TIP detectors 12. The TIP measurement system 21 can be increased or decreased by inserting or removing only the printed circuit board of the measurement system 21.

Next, the operation of the system as described above will be explained. Now, when receiving a TIP scan start signal from the process computer 9, the arithmetic control section 222 first scans the common guide tube 2 via the TIP drive mechanism 5 in order to set the gain of the TIP measurement system 21.
In this case, first select the TIP measurement system 21 and insert the TIP detector 12 into the core top D of the common guide tube 2. The gain of the TIP amplifier 212 is set. Gain setting at this time is performed according to FIG. The position of the common guide tube 2 is usually in the vicinity of the maximum output in the central part of the reactor core, but it is not necessarily the location in the core that indicates the maximum output due to the position of the control rods and the like. Therefore, by core performance calculation by process computer 9,
The power distribution inside the reactor is predicted in advance, and the gain settings at the top of the core D and the information on the process computer 9 side are also set so that the maximum value of the maximum power distribution inside the core is within the operating range of the TIP measurement system 21 during TIP scanning. This is done automatically on the TIP board 20 side. The output of the TIP measurement system 21 includes the fluctuation component of the reactor at the top of the core D, so reading it only once is naturally not accurate. Gain can be set with high precision. By performing the above operations for all of the TIP measurement systems 21, the gain settings of the TIP measurement systems 21 are automatically performed. After the gain setting is completed, all TIP guide tubes 2 . . . are scanned in accordance with a command from the process computer 9 or a predetermined procedure. Manual operation is performed by switching between automatic and manual switching switch 221 when necessary.

Note that the present invention is not limited to the above embodiments. In the above embodiment, the gain setting value at the top of the core D is obtained from the process computer 9,
Although the example in which the gain is set on the TIP board 20 side is shown, the gain may be set on the process computer 9 side. In this case, the arithmetic control section 222 functions as an interface with the process computer 9 side. Further, it is also possible to set the gain only on the TIP board 20 side without using the process computer 9. Since such an extreme power distribution in the reactor does not occur during normal operation, the maximum value of the expected power distribution in the reactor is already low at the core top D during the common scan so that it is within the operating range of the TIP measurement system 21. The gain may be set to a constant value. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

Effects of the Invention Since the present invention is configured as described above, the following effects can be achieved by automatically setting the gain of the TIP measurement system at the top of the reactor core.

In other words, it is possible to set the gain while the TIP detector is being sent from the bottom of the core to the top of the core, but since the detector is sent through a guide tube by wire, accurate positioning is difficult due to slack in the wire, etc.
It is difficult to always calibrate under the same conditions. Therefore
By setting the gain at the top of the core where the TIP detector position is clear, calibration can always be performed under the same conditions.
This eliminates variations in gain settings. Therefore,
The gain setting is no longer too high or too low, and the problem of poor gain setting can be prevented.

Furthermore, since this system sets the gain of the TIP measurement system using the average value read N times, it is possible to improve the accuracy of the TIP measurement system data and to accurately set the gain.

Furthermore, when setting the gain, it is possible to switch between automatic and manual modes, so it can be used in exactly the same way as before, and even if the automatic mode is defective, maintenance can be done easily.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a movable in-core probe monitor system for a nuclear reactor, Fig. 2 is a block diagram of a conventional TIP measurement system, and Fig. 3 shows the main parts of the movable in-core probe monitor system for a nuclear reactor according to the present invention. Figure 4 shows the specific configuration inside the TIP panel.
FIG. 3 is a diagram illustrating gain settings of the TIP measurement system. 1... Reactor pressure vessel, 2... Guide pipe, 3...
Guide tube selection mechanism, 4...shield chamber, 5...TIP
Drive mechanism, 9... Process computer, 12...
...TIP detector, 20...TIP board, 21...TIP measurement system, 22...control system, 212...TIP amplifier,
213...Manual gain setting switch, 214...
Automatic gain setting data memory, 215...Selection circuit, 221...Auto/manual changeover switch, 22
2... Arithmetic control unit.

Claims (1)

[Claims] 1. In a movable in-core probe monitor system in which a movable in-core probe monitor panel measures the neutron flux distribution in the reactor core via a TIP guide tube, the movable in-core probe monitor panel digitally measures the neutron flux distribution in the reactor core through a TIP guide tube. A configurable amplifier, a manual gain setting section that manually sets the gain, and an automatic gain setting section that automatically outputs gain setting data based on external data, and selecting both of these gain setting sections to operate the amplifier. A selection circuit for setting the gain,
an arithmetic unit that controls the reactor site equipment by exchanging data with an external process computer and inputs data for gain setting into the automatic gain setting unit; A movable in-core probe monitoring system for a nuclear reactor, which is characterized in that it is set to a constant value at the top of the reactor core. 2. When setting the gain at the top of the amplifier core, predict the power distribution in the reactor in advance by calculating the core performance using a process computer, and set the gain when the maximum value of the maximum power distribution in the core is within the operating range of the amplifier. A movable in-core probe monitoring system for a nuclear reactor according to claim 1. 3. The nuclear reactor according to claim 1, wherein the gain setting of the amplifier at the top of the core is performed by reading the reactor output N times (N is an integer) and using the average value thereof. Movable in-core probe monitor system.