JPH0385497A - Diagnostic system for abnormal fuel loading - Google Patents

Abstract

PURPOSE:To enable diagnosing abnormal fuel loading accurately and in a short time by comparing loading height information from a refueling machine with specific height information of each equipment and by judging whether the difference stays within a permissible value or not. CONSTITUTION:When a fuel 4 is loaded to a reactor core 6, loading height information is fed from a refueling machine 1 to a refueling computer 8. Also, the computer 8 calculates specific values of a plate guide or the fuel 4 based on a burn-up of the fuel 4 loaded at preset loading co-ordinates, and transfers the value to an abnormality diagnosis device 9 with the loading height information. Subsequently, the device 9 compares loading height information of the fuel 4 with the specific value of the plate guide or the fuel 4, and continues the comparison whole through a fuel handling work along a fuel handling procedure. When an abnormality is judged to exist, an abnormality message is generated and therewith inspection of an reactor inside or a correction work is executed. With these processes, abnormal fuel loading can be diagnosed acculately and in a short time and, when abnormality exists, delay of a periodical inspection schedule can be prevented by applying a countermeausure very early.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a method for refueling a nuclear power plant during refueling work.
The present invention relates to a fuel loading abnormality diagnosis system that automatically diagnoses whether or not fuel loading has been carried out normally.

(Prior Art) At nuclear power plants, fuel replacement work is performed during periodic inspections that are carried out regularly every year.

This refueling work is carried out using a dedicated refueling machine, and abnormalities in the loading condition are detected visually and through experience only when the fuel loading height deviates from a certain range. was.

(Problem to be Solved by the Invention) However, each device handled by a fuel exchange machine, that is, the fuel or the blade guide, has its own unique dimensions, and unless these unique dimensions are taken into consideration, loading errors of each device will occur. cannot be detected with sufficient precision.

The present invention has been made in view of the above circumstances, and its purpose is to provide an abnormality diagnosis system that can accurately detect abnormalities during fuel loading during fuel replacement work.

[Configuration of the Invention (Means for Solving the Problems) The fuel loading abnormality diagnosis system of the present invention measures in advance the unique height dimensions of equipment handled by a fuel exchange machine during fuel exchange work at a nuclear power plant. Or find it by calculation,
An abnormality diagnosis device compares the loading height information obtained when the refueling machine handles the device with the unique height information of the device, and determines whether the difference between them is within an allowable value. It is characterized by diagnosing the fuel loading state based on the following.

(Function) According to the abnormality diagnosis system of the present invention, the presence or absence of an abnormality is determined based on the height information from the refueling machine and the unique values of each device, so if a loading abnormality occurs, it is immediately detected. , and can be determined accurately.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a fuel exchange machine 1 positioned on a fuel exchange floor 2,
This shows a state in which fuel 4 suspended from the fuel exchange machine 1 via the mast 3 is about to be loaded into the reactor core 6 in the reactor pressure vessel 5.

A refueling machine computer 8 and an abnormality diagnosis device 9 are installed in the computer room 7, and these are connected by a signal cable 10.

When fuel 4 is loaded into the core 6, the loading height information is transmitted from the fuel exchanger 1 to the fuel exchanger computer 8, and the loading height information of the fuel 4 is transmitted from the fuel exchanger computer 8 to the fuel exchanger computer 8. The fuel number and loading coordinate data are transmitted to the abnormality diagnosis device 9, where abnormality diagnosis is performed.

FIG. 2 illustrates a method of abnormality diagnosis.

When the blade guide or fuel number and fuel coordinate data are input into the refueling machine calculator (step Sl), the unique value of the blade guide or fuel is calculated based on the fuel burnup (SO) of the preset loading coordinate. (logical height) is calculated (step S2).

Further, when the loading height information of the blade guide or fuel is input in step S3, the abnormality diagnosis device compares this information with the characteristic value of the blade guide or fuel,
It is determined whether the difference between them is within an allowable value (step S4).

This determination is performed sequentially according to the fuel handling procedure until the work is completed (step S5), and during this time, if it is determined that there is an abnormality, an abnormality message (step S8) is issued, and an inspection or modification of the inside of the reactor is performed at step S7. ) is carried out. In addition, in FIG. 2, the chain line indicates the flow of the abnormality diagnosis method.

The aforementioned calculation of the eigenvalue (theoretical height) of the fuel or blade guide is performed as follows.

It is known that the length of the fuel increases as the burn-up increases during operation of a nuclear reactor. Therefore, if the burnup of the fuel is known, the calculated height of the fuel, that is, the eigenvalue, can be determined from the burnup based on the irradiation elongation curve f (X) in FIG. In addition, in Figure 3, zFO
and βl indicate the height and allowable range of the new fuel, and ZFx and β2 indicate the height and allowable range of the irradiated fuel.

On the other hand, the blade guide is used temporarily during fuel replacement, and as shown in FIG. 3, its characteristic value ZDB is determined by manufacturing dimensions, regardless of the operation of the nuclear reactor. Further, the allowable range α is set based on measured values collected in advance including the measurement system.

From the above, it is possible to determine the respective eigenvalues (theoretical heights) and their allowable ranges for the fuel or blade guide.

In this manner, when replacing fuel, it is possible to timely and accurately diagnose whether or not the fuel is loaded in a normal state by sequentially handling the fuel or the blade guide according to the fuel replacement procedure.

[Effects of the Invention] As explained above, according to the fuel loading abnormality diagnosis system of the present invention, fuel loading abnormality can be diagnosed accurately in a short time.
If there is an abnormality, it can be dealt with at an early stage and delays in the periodic inspection process can be prevented, which is an excellent effect.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing an abnormality diagnosis method, and FIG. 3 is a graph explaining a method for determining setting values necessary for abnormality diagnosis. 1...Fuel exchange machine 2...Fuel exchange floor 3...Mast 4...Fuel 5...Reactor pressure vessel 6...Core 7...Computer room 8...Fuel replacement Computer calculator 9...
・・・・Abnormality diagnosis device 10 ・・・・・Signal cable

Claims (1)

[Claims] During refueling work at a nuclear power plant, unique height information of the equipment (fuel or blade guide) handled by the refueling machine is determined in advance by measurement or calculation, and when the refueling machine handles the equipment. An abnormality diagnosis device compares the loading height information obtained at the time with the unique height information of the device, and diagnoses the fuel loading state based on whether the difference between them is within an allowable value. Features fuel loading abnormality diagnosis system.