JPS62174692A - Burnup distribution measuring device in 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 (a) Purpose of the Invention [Field of Industrial Application] The present invention relates to an in-reactor burnup distribution measuring device for grasping the burnup distribution in a core of a nuclear reactor.

[Prior art] In a nuclear reactor, fuel burnup, which is the sum of thermophotogenic materials per unit ttia of fuel, is an important parameter in the design of a replacement core, and it is important to understand the burnup distribution within the core. There is a need.

In order to evaluate this unique burnup distribution, conventionally, the in-furnace cylinder was used! ll
The power distribution from the Type 11 Neutron East Detector (M/D) was used, and the M/D mapped the power distribution inside the reactor, and the data was processed by a computer to determine the burnup. However, if the output distribution changes frequently, constant monitoring of the output distribution by M/D is recommended.
It is practically difficult due to the problem of i43Δ, and therefore, it is difficult to calculate the burnup value (11 Appearance was requested.

[Problems to be solved by the invention] This invention has been made in view of the above circumstances, and has solved the problem of dealing with frequent changes in output level and output distribution, which the conventional technology has. The purpose is to provide a burnup distribution measurement device within a nuclear reactor.

(B) Structure of the invention [Means for solving the problem] In response to this purpose, the in-reactor burnup distribution measuring device of the present invention is connected to a movable in-reactor neutron flux detector and an in-reactor thermocouple. a horizontal power distribution calibration device that calibrates the output distribution of the thermocouple to the output distribution of the in-reactor movable neutron flux detector using a correction coefficient from a constant file to create a horizontal power distribution; a burnup fI calculation device connected to the horizontal power distribution calibration device and the ex-core neutron flux detector and synthesizing the horizontal power distribution and output level; and a burnup fI calculation device connected to the burnup integration device and output of the burnup integration device. The present invention is characterized by comprising a burnup distribution display device that visually displays the burnup distribution.

The details of this intervention will be explained below with reference to the drawings showing one embodiment.

In the figure, in J3, reference numeral 3 is a horizontal power distribution calibration device, 4 is a burnup integration device, 5 is a burnup distribution display device, 6 is a movable in-core neutral flux detector (M/D), and 7 is outside the reactor. A neutron flux detector (E/D) and 8 are thermocouples (T/C), which are connected to each other in the relationship shown. In addition, the code|symbol 9 is a nuclear reactor.

The horizontal power distribution calibration device 3 also adjusts the temperature distribution measured by the thermocouple 8 to match the horizontal power distribution obtained based on the neutron flux distribution measured by the movable in-reactor neutron flux detector 6. This device extracts a correction coefficient, which is a constant, from a constant file 2 and multiplies it by the output distribution obtained. Further, the burnup integration device 4 is a device that calculates the product of a horizontal output P, which will be described later, and an output level Q, and integrates the product for the operating time.

In the constant file 2, the horizontal power distribution inside the reactor 9, which was obtained from the design data through analysis in advance, is stored in the input device 1.
It is stored through. The actual three-dimensional in-reactor power distribution during reactor operation can be determined in detail at regular intervals as in the past using the movable in-reactor neutron flux detector eI6.
At the same time, the temperature distribution based on the in-furnace power distribution is constantly measured in the horizontal direction by the thermocouple 8, and is input into the horizontal distribution calibration device 3. That is, the horizontal power distribution calibration device 3
Therefore, at any (X, Y) point, the output horn distribution by the movable in-core neutron flux detector 6 which is closest to the horizontal temperature distribution obtained by the thermocouple 8 when measuring the output distribution by the pair 8 is obtained. is selected from the constant file 2, the above correlation coefficient f xy is obtained by simply comparing the corresponding points, and this! 1, the power distribution of the thermocouple 8 can be easily calibrated against the power distribution of (q) by the in-core neutron flux detector 6. In this way, the horizontal power distribution calibration P .

On the other hand, the extra-core neutron flux detector 7 constantly measures the J level Q output.

The horizontal output distribution P thus obtained.

and the output level Q are synthesized by the burnup integration device 4 according to the following equation.

B, = fQ - Px, d t/fCJ However, in the above equation, t is the combustion time.

Burnup distribution Bx obtained as described above.

(usually called a map) is displayed by a burnup distribution display device 5 (for example, a CRT or a printer).

"Operation" The horizontal distribution calibration device uses correction coefficients based on a constant file determined in advance by analysis to calculate the power distribution obtained by the thermocouple by the movable in-reactor neutron flux detector (q). Compare and calibrate the output portion A and create the horizontal output distribution.

On the other hand, the output level is increased by 1!7 based on the signal from the ex-core neutron flux detector. The output norm and the horizontal power distribution obtained in this way are combined by a burnup integration device, and the burnup distribution can be grasped with high accuracy at all times.

(C) Effects of the Invention According to this invention, the output distribution of thermocouples, which can constantly monitor the horizontal output distribution, is determined by the in-core neutron flux detector using the horizontal output distribution calibration device. Since it can be easily calibrated for the burn-up distribution in the reactor, it is possible to obtain a burn-up distribution measuring device in the reactor that can constantly measure the burn-up distribution with high accuracy.In addition, it is possible to obtain useful information for reactor operation online! be able to.

[Brief explanation of drawings]

The figure is a block diagram of an in-reactor burnup distribution measuring device according to an embodiment of the present invention. 1...Input device 2...Constant]? Il 3...
・Horizontal power distribution calibration device 4... Burnup integration device 5... Burnup distribution display device 6... Movable in-core neutron flux detector 7... Out-of-core neutron flux detector 8
...Thermocouple 9...Nuclear reactor

Claims (1)

[Claims] Connected to the movable in-core neutron flux detector and in-core thermocouple,
a horizontal power distribution calibration device that uses the output distribution of the thermocouple as a correction coefficient from a constant file to calibrate the output distribution of the in-reactor movable neutron flux detector to create a horizontal power distribution; a burnup integration device connected to the directional power distribution calibration device and the ex-core neutron flux detector to synthesize the horizontal power distribution and output level; and a burnup integration device connected to the burnup integration device to visually display the output of the burnup integration device. A burn-up distribution measuring device in a nuclear reactor, comprising: a burn-up distribution display device for displaying a burn-up distribution in a nuclear reactor;