JPH0119116B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a nuclear reactor power control device for a nuclear power plant.

Generally, the output of a nuclear reactor is adjusted by inserting or withdrawing a large number of control rods into the reactor core one by one.

This operation is normally performed by the operator while checking the control rod position, so if an abnormality occurs in the control rod position indicating system, the operation must be prohibited or it will be tantamount to blind operation, which poses a safety problem.

Conventionally, reactor safety was ensured by prohibiting the operation of all control rods if the position of even one control rod became unknown.

However, although this method ensures the safety of the reactor, even if the unknown control rod is in a position where its influence on other control operations can be completely ignored, for example, it may be in the fully withdrawn position from the previous operation. Even if the position of a control rod that is known with certainty becomes unknown, the operation of other control rods is prohibited, making it impossible to adjust the reactor's output at all.

The present invention removes such defects and ensures the safety of the reactor, and even if the control rod position becomes unknown, it allows the operation of other control rods depending on the conditions, so that the reactor can be operated. The purpose of the present invention is to provide a nuclear reactor power control device that enables output adjustment.

Hereinafter, an example in which the present invention is applied to a BWR type nuclear reactor will be described with reference to the embodiments shown in the figures.

FIG. 1 shows a block configuration diagram of a nuclear reactor power control device according to an embodiment of the present invention, in which 1 is a control rod drive control section, 2 is a control rod drive mechanism, 3 is a nuclear reactor, and 4 is a control rod, 5 is a control rod position reading processing section, 6
7 is a control rod operation determining section, and 7 is a control rod position indicating system interlock gate section.

When operating a control rod, the content of the request is input to the control rod drive controller 1 as a control rod operation request signal a. This signal a is as follows: a=a (a ₁ , a ₂ , a ₃ , a ₄ , a ₅ ~ a ₈ , a ₉ ~ a ₁₂ )
......(1) where _a1 is continuous extraction state, _a2 is extraction state, _a3 is insertion state, _a4 is emergency insertion state, _a5 ~
_A8 is composed of 12 bits indicating the x-coordinate of the control rod requiring operation, and _a9 to _a12 indicating the y-coordinate of the control rod requesting operation.
For example, assuming that control rods with x=11 and y=12 are pulled out, a=a (0, 1, 0, 0, 1011, 1100)
becomes.

The control rod drive control unit 1 receives a control rod operation interlock signal b input from another system, for example, to check whether the control rod to be operated currently conforms to a predetermined operation procedure or whether the drive mechanism is normal. control rod position indicating system interlock gate section 7, as will be described later.
Based on the control rod position indication system interlock gate signal f output from the control rod position indication system interlock gate signal f, it is determined whether or not the control rod can be operated, and if the control rod can be operated, the control rod drive electric signal c corresponding to signal a is specified by signal a. output to the control rod drive mechanism 2 of the control rod. The signal c can be expressed as c=c(c ₁ , c ₂ , c ₃ , c ₄ )...(2) where c ₁ is the drawing supply valve driving state,
It consists of 4 bits: c ₂ indicates the drive state of the extraction/discharge valve, c ₃ indicates the drive state of the insertion/supply valve, and c ₄ indicates the drive state of the insertion/discharge valve. For example, in the case of extraction, c=c(1, 1,
00).

The control rod drive mechanism 2 receives this signal c,
It is converted into a water pressure signal d for driving the control rod, and the control rod 4 is driven.

On the other hand, the control rod position is inputted to the reactor 3 as a control rod position signal e by a reed switch built into each control rod 4. This signal e can be expressed as e=e(P,X,Y)...(3). Here, P=P(P ₁ ~
P ₁₁ ), 11 bits represent the insertion or withdrawal position of the control rod, X = X (x ₁ ~ _{x 4} ), 4 bits represent the x coordinate of the control rod, and Y = Y (y ₁ ~ _{y 4 )} . )in,
4 bits represent the y-coordinate of the control rod.

The control rod position reading processing unit 5 receives control rod position signals e from all control rods 4 loaded in the reactor 3.
and determine whether each signal has regular control rod position data. This means, for example, whether the data is in the bit position where it should be,
This can be determined based on whether or not there are any bits that do not satisfy predetermined conditions. As a result, if even one signal e is not normal, it is assumed that the control rod position indication system is abnormal and the control rod position indication system interlock signal f ₁ =0 is output in order to prohibit the operation of the control rod 4. . In this case, if all the signals e are regular signals, f ₁ =1.

If a non-regular signal exists in the signal e, the control rod position reading processing unit 5 simultaneously stores the normal position data of these non-regular signal control rods, and their x and y coordinates as non-regular control rod data g. It is output to the operation determining section 6. That is, this data g can be expressed as g=g(P _j , X _j , Y _j )...(4), P _j =P(P _1j ~P _11j ), j=1
~ m, P _j represents the normal position data of the control rod of the non-regular signal, and m represents the number of control rods of the non-regular signal. _{In addition ,} X _j is _{the x} coordinate _of the control rod _{as X j =}
y _4j ) represents the control y-coordinate. In other words, the control rod position reading processing unit 5 stores the position data of each control rod from the previous operation, and when the control rod position indication system becomes abnormal, the normal position of the control rod before the abnormality occurs. Output data.

The control rod operation determination unit 6, as shown in FIG.
Control rod data input section 61, output variation calculation section 6
2. The control rod data input section 61 is composed of a control rod operation permission determination section 63, and outputs control rod data i based on the irregular control rod data g and the control rod operation request signal a. This data i can be expressed as i=i{a ₅ to a ₈ , a ₉ to a ₁₂ [g]} (5). Here a ₅ ~ a ₈ , a ₉ ~ a ₁₂
represent the x-coordinate and y-coordinate of the control rod to be performed as described above, and [g] represents the transformation data having the same contents as g. In other words, the control rod data input section 61 converts the irregular control rod data g into data [g] that can be processed by the output fluctuation amount calculation section 62, and outputs it together with the control rod coordinate data to be operated.

The output fluctuation amount calculation unit 62 calculates the control rod data i.
From this and the reactor data j from other systems, the reactor output fluctuation amount k caused by operating the control rod that is about to be operated is calculated. The reactor data j is composed of a data group indicating the current physical state of the reactor, including power distribution, coolant distribution, etc. within the reactor.

The control rod operation permission determining unit 63 compares the calculated variation amount k with a pre-stored tolerance value k _p , and if it is within the tolerance value, outputs a control rod operation permission gate signal h=1.

In this way, when the control rod position becomes unknown, the control rod operation determination unit 6 determines which control rod to operate from now on based on the normal position data before the control rod became unknown and the current core state. It is determined whether the safety of the reactor is ensured even if the operation is performed, and if it is safe, the signal h = 1, and if there is no guarantee, the signal h =
Outputs 0.

Control rod position indication system interlock gate section 7
As shown in FIG. 4, it is composed of an OR gate, and outputs the logical sum of signals _f1 and h to the control rod drive controller 1 as a control rod position indicating system interlock signal f.

As a result, even if an abnormality occurs in the control rod position indication system, control rod operations are not uniformly prohibited.
If the safety of the reactor is ensured, normal control rod operations of other control rod position indication systems are permitted;
It becomes possible to adjust the output of the nuclear reactor.

Although the above embodiment has been described using a hydraulic drive mechanism as the control rod drive mechanism, it goes without saying that the same effects as in the above embodiment can be obtained using an electric motor drive mechanism. do not have. Furthermore, it goes without saying that the present invention is applicable not only to BWR type nuclear reactors but also to other types of nuclear reactors such as FBR.

As described above, according to the present invention, even if the position of the control rod is unknown, the control rods can be operated under certain conditions, and when the nuclear power plant is operated in a system, the nuclear power plant can be operated with reliability. Furnace power control device can now be obtained.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a reactor power control system showing an embodiment of the present invention, Fig. 2 is a block diagram of its control rod operation determination section, and Fig. 3 is a block diagram of its control rod position indicating system interlock gate section. FIG. 1... Control rod drive control section, 2... Control rod drive mechanism,
3... Nuclear reactor, 4... Control rod, 5... Control rod position reading processing section, 6... Control rod operation judgment section, 7... Control rod position indication system interlock gate, 61... Control rod data input section, 62... Output fluctuation Quantity calculating section, 63... Control rod operation possibility determining section.

Claims (1)

[Claims] 1 A control rod drive control section that drives and controls the control rods in the reactor via a drive mechanism based on a control rod operation request signal that represents the control rod coordinates and operation details, and a control rod that instructs the position of each control rod. In the reactor power control device of a nuclear power plant that has a position indication system,
When an abnormality occurs in the control rod position indicating system and the control rod position becomes unknown, a first signal is output, and control rod data representing the coordinates of the control rod that has become unknown and its normal position is output. A control rod position reading processing unit determines whether or not the control rods can be operated based on the control rod request signal, the control rod data, and the reactor data representing the state of the reactor. A control rod operation determination section that outputs a signal, and when the control rod operation determination section outputs the second signal when the control rod position is unknown, the signal is added to the control rod drive control section to control the control rod. and a control rod position indicating system interlock gate section that allows the control rod to be driven, but adds the first signal to the control rod drive control section and prohibits the drive of the control rod when the second signal is not output. A nuclear reactor power control device characterized by comprising: