KR830001225B1 - Reactor safety system - Google Patents

Abstract

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Description

Reactor safety system

1 schematically shows a safety system according to the invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a safety system for a nuclear reactor, and more particularly, to a safety system in which digital modulus is performed in which data can be processed in parallel for continuous and repetitive calculation of a parallel function representing a percentage of maximum power load. It is about.

Conventional safety systems for reactors have performed digital calculations as part of the reactor protection system. These methods are performed as standard digital techniques as used in computers. The basis of this technique is the use of stored programs to convert input signals into digital form, store them in memory and process the display of stored data and output. All these functions are performed in sequence in the time domain by a single central computer.

The drawbacks of this prior art system are the complexity of the program, which in turn takes a lot of time to calculate and must process the individual measured parameters in a sequential manner. This normal sequence involves performing a continuous calculation and accepting data parameters to provide data at the end of the calculation to determine whether the reactor is in the safe operating area.

Another problem with these prior art devices results from the characteristics of digital computers that operate to lose data identity except for address locations. Therefore, program tracking and error correction in the system are time consuming and difficult. In addition, this sequential computer system, which is continuously thoroughly inspected and reviewed to ensure proper safety control, requires that each measured parameter that affects safety has a feasible number and equation that relates to all other parameters.

For example, the reactor temperature has 4000 different feasible figures, the pressure has 4000 different feasible figures, and the liquid oil etc. has 4000 feasible figures, which in turn is feasible input to the sequential calculator. The number of states is 4000 cubes. Thoroughly examining it at the rate of every 1 / 10th of a second takes hundreds of years. Therefore, other devices have been used to ensure that there are no defects in the program of the safety system. This will be done by more review and long-term review by independent technical groups and regulatory bases.

The present invention solves the problems associated with prior art systems while at the same time providing a safety system to the reactor using parallel combinations of calculations that accept data based on specific parameters and create added functions. Solve. Therefore, each individual function of this parallel set consists of a combination of parameters and a set of constants. Each parameter is independently converted to a function of that parameter so that a check is made between that parameter and the output using all possible states of that parameter.

Using the already described example of each parameter having 4000 possible states, the number of feasible states to be examined is not 4000 tax grades, but three thousand, or 12,000, feasible states. If the rate is one test per 1/10 second, the test takes about 30 minutes. The system was then thoroughly checked with all possible values of the parameter applied to the input and checked to determine whether all the functions of the parameter on the analog output were correct. This allowed both input and output to be analog-checked for each individual parameter.

Another advantage of the present invention is that the parameters can be easily changed, and the sum of the constants added to the calculation method for performing the function calculation can be easily added. This modified function can be adjusted to any desired numerical value.

In view of the foregoing, one aspect of the present invention is to provide a nuclear reactor with a safety system that generates safety control signals by individually calculating the function of several parameters that affect the safety of the reactor.

Another aspect of the present invention is to provide a nuclear reactor with a safety system that can be thoroughly inspected with all feasible values of parameters affecting the safety of the system.

Various embodiments of the invention will become more clearly understood upon a review of the following detailed description with reference to the drawings.

The accompanying drawings are shown for the purpose of describing one embodiment of the invention in detail and are not intended to limit the invention. FIG. 1 shows a nuclear reactor safety system that generates a control signal S indicating the percentage of nuclear reactor power limit. This signal S is compared with the reference signal R representing the reactor electric power in the comparison amplifier 12. The comparison circuit 12 generates an alarm signal or a stop signal at the reactor (not shown) whenever the control signal S is equal to or slightly smaller than the power signal R.

The control signal S is expressed as the sum of various measured reactor parameter functions as follows.

S = f (P) + f (T) + f (ø _T ) + f (ø _B ) + f (W)

From here;

f (P) = A ₀ + A ₁ P + A ₂ P ² +... A _X P ^X f (ø _B ) = D ₀ + D ₁ ø _B + D ₂ øB ² . D _k øB ^k

f (T) = B ₀ + B ₁ T + B ₂ T +... B _y T ^y f (W) = E ₀ + E ₁ W + E ₂ W ² . E _m W ^m

f (ø _T ) = C ₀ + C ₁ ø _T + C ₂ ø _T ² +… C _Z ø _T ^Z

Where A's, B's, C's, D's and E ₁ ^s are constants selected appropriately for safety functions precomputed by some criterion (eg least squares), where P = reactor pressure, T = reactor temperature, ø _T = neutron flux from the top of the reactor, ø _B = neutron flux from the bottom of the reactor, and W = cooling fluid flow in the reactor.

The precalculated parameters P, T, ø _T , ø _B and W for each sensed reactor parameter are determined by a thermohydraulic experiment that determines the maximum amount of heat that can be removed from the specific volume of the reactor. .

For example, the pressure parameter P function can be determined experimentally as follows.

f (P) = A ₁ P + A ₂ / P ²

This experimentally derived equation fits the polynomial of the type shown in the following parameters of the safety system 10 for all available values of P. A ₀ , A _l , A ₂ . The values of A _X are set to the required precision allowed. Indeed, polynomials cannot be properly represented by expressions below the tertiary term of P.

In the same way, the functions of T, ø _T , ø _B and W are experimentally derived and fit properly with a third or lower polynomial. The suitability of these experimentally derived expressions and polynomials is well known to those skilled in the art and will not be described here for the sake of brevity.

Reactor parameters in the safety system 10 are sensed by transducers suitably located within or in contact with the surface in a manner known to those skilled in the art. These measured parameter signals P, T, ø _T , ø _B and W are amplified separately by the respective amplifiers 20a, 20b, 20c and 20d, 20e, and each amplified signals are Analog to digital converters 22a, 22b, 22c, 22d and 22e connected in series to amplifiers 20a, 20b, 20c, 20d, and 20e. Is converted.

Each function f (P) above to form a control signal S, f (T), f (ø T), f (ø B), f (W) is a microprocessor (14a), each connected in parallel, (14b), It is calculated in (14c), (14d), and (14e), respectively. The microprocessors 14a, 14b, 14c, 14d, and 14e are memory sections 16a, 16b, 16c, 16d, 16e, and program sections 18a, 18b, 18c, 18d, and 18e, respectively.

The operation of the safety system 10 is well illustrated by the same operation which takes place simultaneously in each parameter P, T, ø _T , ø _B , W of the detected reactor as described and generated in parameter P.

The numerical value of the state of the parameter P (pressure) is then sensed by means of a transducer located appropriately in or on the reactor to provide a measured value. This measured pressure P analog value is transmitted to an amplifier 20a which amplifies and filters the analog pressure P signal before being sent to the analog-to-digital converter 22a which forms a digital signal corresponding to the analog amplified signal with respect to the pressure P. . The digital signal corresponding to the measured pressure P signal is transmitted along the line 24a and each polynomial representing the pressure signal P measured along the parallel terminal of the line 24a to the program unit 18a of the microprocessor 14a. It is input simultaneously to the components. The program portion 18a of the microprocessor 14a is then subjected to several pre-calculated constants A ₀ , A ₁ , A ₂ ... Which are stored in the memory portion 16a of the micro processor 14a. Requires input of A _X and the constant is supplied to program portion 18a. The program unit 18a then calculates a digital value for the polynomial stored in the program unit 18a. The digital value of the polynomial or f (P) is then transmitted via the line 26a to the digital analog converter 28a which yields the analog value of the calculated equation of the function f (T).

The enumerated type of calculation that forms the function f (P) may consist of a single chip microprocessor available on the market. This microprocessor is model number 8085 manufactured by Intel Co., Ltd .. Microprocessors of this type are also suitable for all microprocessors 14a, 14b, 14c, 14d and 14e.

Although already described, all microprocessors 14a, 14b, 14c, 14d and 14e are operated simultaneously in the same way on their respective parameters to determine their function from the polynomial calculation of their programmed function. Calculate the number of parameters. Expression of the function calculated then all of them at once f (P), f (T), f (ø _T), f (ø _B), f (W) are added together by the adding stage (30) compared to the reference signal R Provides the above-described control signal for generating the safety alarm signal A.

Many new and modifications may be made by those skilled in the art upon reading the specification of the present invention. All such new and modifications have been removed here for brevity and conciseness, but are within the scope of the following claims.

Claims (1)

In a safety system for a reactor, a series of transducers are installed to measure various parameters of the reactor's operation, and one parameter for the reactor's operation is calculated to calculate a function of the parameter that represents the percentage of the reactor's total load. A series of parallel-connected microprocessor stages, each individually connected to one of the measuring transducers, are installed, receiving and summing all the functional outputs of each microprocessor stage and adding them to generate a control signal representing the actual percentage of power operation of the entire reactor. Reactor safety system with stages installed.

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