SU1607018A1 - Device for emergency protection of nuclear reactor - Google Patents

Abstract

The invention relates to nuclear reactor control and protection systems and can be used in emergency signal generation circuits based on a period signal. The purpose of the invention is to increase the speed without noise immunity. The nuclear reactor emergency protection device contains a logarithmic element, an inertial differentiation device, a setpoint adjuster and a comparison circuit. Introduction of a peak detector, divider, second comparison circuit, one-shot, inverter and JK-trigger, connected in a special way, allows to generate an alarm not by the value of the steady-state period, but by the nature of the signal change, inversely proportional to the period, during a short time interval . This makes it possible to increase the speed of the device, to reduce the delay in the formation of an alarm signal during reactivity jumps. In addition, a delay element, an additional divider and a third comparison circuit can be introduced into the device, which increases the noise immunity of the device. 1 hp f-ly, 3 ill.

Description

The invention relates to nuclear reactor control and protection systems and can be used in emergency signal generation circuits based on a period signal.

The purpose of the invention is to increase the speed without reducing noise immunity.

Figure 1 shows a structural diagram of a reactor emergency protection device; Fig. 2 shows the time diagrams of the input voltages U of the corresponding elements of the device in the presence of interference (diagrams. a — emergency shortening of the period; diagrams b — non-dangerous jump of reactivity); FIG. 3 are graphs of the rise time t of the signal inversely proportional to the period (at the output of the differentiating device) when reactivity jumps are applied depending on the set period of the reactor T for an RBMK type reactor at different constant measurement times of .0 and the setting corresponding to the allowable period 10, the Emergency Nuclear Device Protection Device (FIG. 1) contains a logarithmic element 1, inertial

thirty

25

differentiating device 2, preset- JfiK 3 setpoints, two circuits 4 and 5 of comparison, peak detector 6, divider 7, one-shot 8, inverter 9 and trigger 10.5

In addition, the device may contain a delay element 11, an additional divider 12, and a third comparison circuit 13.

The device operates as follows (figure 2).

I A signal, i.e., inversely proportional to period T, is formed with a given t5. The time required at the output of the inertial differentiating device 2. Yerva comparison circuit 4 generates a start signal of the one-shot 8 / if the signal (1 / T) exceeds the setpoint U 20 of the sensor 3 setpoint . Peak detector 6 registers the maximum signal value (1 / T), which decreases by a predetermined value of 0. (here S depends on the signal at the output of the peak detector) by a divider 7 (U) The trigger 10 is set to the input. A single state, which means the operation of the emergency protection device (Fig. 2, diagram a). The device is reset by the R-input of the JK-flip-flop 10. On the Q, during the course of three of 10, a zero potential is formed under the assumption that the right logic is used.

If at the moment of termination of the pulse Ug of the one-shot 8 (figure 2, diagram b5, the current value of the signal Ug at the output of the inertial differentiating device 2 does not exceed the value of the output voltage U of the divider 7, then the signal Uj at the output of the second comparison circuit .5 is equal to logical zero and JK-trigger, 10. does not work (FIG. 2, diagrams b).

The constant time aperiodic tg of the inertial differentiating device 2 and the pulse duration t of the one-shot 8 are chosen in accordance with the claims. To do this, you can use the dependencies presented in FIG. So, for example 30

35

40

45

50

increase the speed of the emergency protection device in the most dangerous modes.

In the presence of interference, if the maximum per modulus noise value does not exceed 0.5o, then the device is not allowed to fail when the signal decreases at the moment of the end of the specified and time limit by. When the signal is equal to the maximum value, the device triggers.

Depending on the properties of the reactor, the nature of the signal decay, which is inversely proportional to the 1 / T period, after reaching a maximum may be different. If the analysis of the falling part is not needed, you can add an additional one, a condition that ensures checking only if a signal 1 / T jump of a given value has occurred.

The device may further comprise a delay element 11, an additional divider 12 and a third comparison circuit 13. A single signal at the output of the third comparison circuit 13 is formed when the signal at the output of the additional signal divider at the output of the delay element 11, i.e. if the signal, which is inversely proportional to the period, increases by a specified amount over a given period of time. The one-shot 8 is triggered by the presence of single signals at its input and control input. Such a one-shot can be a HH analysis, for example, in the form of sequentially from the AND circuit and a single-shot with one trigger input. The rest of the device works similarly. The division factor — the additional division of the body 12 and the delay of the delay element 11 are selected from the condition of registering dangerous jumps and taking into account the noise immunity requirements.

The advantage of the device is that the alarm is generated not by the value of the established period, but by the nature of the change from the inversely proportional period over a short period of time. This increases several times the speed of the accident protection device in the most dangerous mode, for an acceptable steady-state period, for example, if you enter a large period of 10 s, you can select 146 seconds.

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and about 0.2 s or 0,2 0.288 s and & - 0, 8 s

l

etc. The possibility of choice (7 in the range of 0.1–0.5 s permits in several

the magnitude of the positive jump of the reaction T1 of the atti- and with a fast decrease of the period. Another positive effect is that

five

five

50

0

five

0

five

0

increase the speed of the emergency protection device in the most dangerous modes.

In the presence of interference, if the maximum absolute value of the noise does not exceed 0.5 °, then the device will not operate if the signal decreases at the moment when the specified time interval ends. When the signal is equal to the maximum value, the response of the device is guaranteed.

Depending on the properties of the reactor, the nature of the decay of the signal, inversely proportional to the period 1 / T, after reaching a maximum may be different. If the analysis of the falling part is not needed, you can add an additional, condition that provides a check only if a 1 / T signal jump of a given value has occurred.

The device may further comprise a delay element 11, an additional divider 12, and a third comparison circuit 13. A single signal at the output of the third comparison circuit 13 is formed when the signal at the output of the additional divider 12 exceeds the signal at the output of the delay element 11, i.e. if the signal is inversely proportional to the period, increases for a given period of time by a specified amount. The one-shot 8 is triggered when there are single signals at its input and a control input. Such a one-shot can be analyzed, for example, in the form of a series-connected AND circuit and a one-shot with one trigger input. The rest of the device works similarly. The division factor-the additional divider 12 and the delay of the delay element 11 are selected from the condition of registering dangerous jumps and taking into account the requirements of noise immunity.

The advantage of the device is that the alarm is generated not by the value of the steady state, but by the nature of the signal change, inversely proportional to the period, during a short time interval. This increases several times the speed of the emergency protection device in the most dangerous modes, for example, when entering large

the magnitude of the positive jump in the reaction of T1 atti- nity and with a rapid decrease in the period. Another positive effect is that the delay

five . The 16070 generation of the alarm signal is the same for any type of change, the period of the reactor.

The positive effect of the proposed device 1m, can be obtained by using it in the systems of emergency protection of the nuclear reactor, along with traditional means.

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Claims (2)

1. Emergency protection device of a reactor containing a logarithm element, the input of which is HAVE-) 5 is the device input, an inertial differentiating device with a given aperiodic constant time, the input of which is connected to the output of the logarithm element, setpoint adjuster 20 and the first comparison circuit, the first the input of which is connected to the output of the setpoint adjuster, and the second to the output of the inertia differentiating device, characterized in that, 25 with the purpose of speeding up without reducing the noise immunity, s peak detector, divider;., second comparison circuit, one-shot, JK-trigger, and the input peak detector one The torus and the first input of the second comparison circuit are connected to the inode code of the differentiating device, the output of the peak detector is connected to the input of a divider, the output of which is connected to the second input of the second comparison circuit, the output of the first comparison circuit is connected to the input of the one-vibrator, the output of one vibrator through the inverter is connected to the synchronous input JK-flip-flop, to the J-input of which the output of the second comparison circuit is connected, a potential zero is connected to the K-input, the setup input of the JK-flip-flop is the device reset input, and the output is the output device ode. 2. The device according to claim 1, 1, and that is, because it introduces a delay element, an additional divider and a third comparison circuit with the inputs of the delay element and an additional divider connected to the output of the inertia differentiating device, the first input of the third comparison circuit is connected with the output of the additional divider, the second with the output of the delay element, the output of the third comparison circuit is connected to the control input of the one-shot. . Rie .; and and AT  T and. and. ten and, Rig. 2 t .. 0.45 0.35 0.25 0.15 10 20 .... Fig.Z Compiled by O.Bozhenkov Editor A.Makovska Tehred M.Hodanich - Proofreader L.Beskid Order 13552, Circulation 347Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. D. 4/5 of 1.5 s thirty T „. With