RU2798480C1 - Method for controlling and protecting a fast neutron nuclear reactor and a system for its implementation - Google Patents

Abstract

FIELD: nuclear energy.

SUBSTANCE: invention relates to a method for controlling a nuclear reactor, mainly a fast-neutron reactor. The absorber rod control equipment includes a program control device that receives a signal from a power level sensor, an energy production counter and a position sensor, and transmits through the absorber rod selection selector the function of automatic power control from one absorber rod to another absorber rod in such a way that the absorber rod moves by forming certain sinking profile of the system of absorbing rods.

EFFECT: increased average coolant temperature at the core outlet and the possibility of increasing the reactor power without increasing the coolant flow rate by providing dynamic profiling of the energy release field and reducing the unevenness of the coolant temperature field at the core outlet, as well as the possibility of reducing the maximum shell temperature of fuel elements, which increases reliability and safety.

2 cl, 1 dwg

Description

Technical field

The invention relates to nuclear energy, and in particular to a method for controlling a nuclear reactor (NR), mainly on fast neutrons with a long campaign duration and an unambiguous dependence of the reactivity margin for fuel burnup on the value of the reactor power generation, with compensation for the reactivity margin and the performance of other functions of the control and protection system (CPS) absorbing rods (PS) placed in the active zone. At the same time, a strictly unambiguous dependence of the reactivity margin for fuel burnup on the value of reactor power generation implies the use of a given power output schedule and the CPS SS movement algorithm to compensate for fuel burnup, power and temperature effects of reactivity, as well as operational power control (which, for example, is typical for reactor operation in basic power generation mode). Deviations from the given schedule of power output at a given power output for fast neutron reactors do not lead to noticeable deviations in the considered dependence of the fuel burnup reactivity margin on the reactor power output value, since these deviations are significantly less than the burnup reactivity margin.

State of the art

It is known that in order to improve the technical and economic indicators, it is necessary to form the distribution of the energy release field in the reactor, which provides the most favorable temperature conditions for the operation of the core elements. This is achieved, for example, by physical profiling of the nuclear reactor core fuel load using different uranium enrichment in different radial zones.

However, during the operation of the reactor, due to different fuel burnup, the initial distribution of the energy release field may change. This will be most significant for nuclear reactors with a long fuel campaign, operating without partial refueling/rearrangement of fuel assemblies. Therefore, in such nuclear reactors, as an additional means of equalizing the temperature distribution of the coolant at the exit from the core during the campaign, SS located in the core can be used, which control the neutron power of the reactor and compensate for the reactivity margin for burnup. To this end, PSs located in those areas of the core where it is advisable to increase the energy release are removed in the process of burnup ahead of the PSs located in those areas where the energy release, on the contrary, needs to be reduced (M.A. Shults. Regulation of nuclear power reactors. Publishing House of Foreign Literature, Moscow, 1957).

The above problem is less relevant for nuclear reactors operating with partial fuel refueling, since in such nuclear reactors the distribution of the energy release field can also be effectively influenced by fuel refueling scenarios.

Reactors with a large number of PSs that perform combined functions of reactivity margin compensation, automatic power control and emergency protection (EP), with unified actuators (IM), similar to the IM of the control and protection system, have the greatest opportunities for influencing the power release field using the PS control algorithm. (CPS) of VVER-1000 reactors (CPS of VVER-1000). In such reactors, a certain sequence of movement of CPS PS groups in the core, located symmetrically at different radii, is incorporated into the CPS absorber rod program control system. However, in VVER-1000 reactors, due to the use of the second (main) system for compensating the reactivity margin for burnup in the form of adding boric acid to the coolant, almost all CPS in the power mode of the reactor are removed from the core to the upper position and on the distribution of the energy release field of influence do not provide.

Patent application US4717528A proposes a control rod control system for a nuclear reactor to control the distribution of power throughout the core. The system includes computing devices that provide calculation of the differential efficiency of absorbing rods, the energy release field in a nuclear reactor, control of the burnup distribution, partial power reduction, formation of a strategy for moving the absorbing rods, ensuring minimization of uneven energy release and fuel burnup in the core. However, since the application of such a solution is considered for PWR reactors, in which the reactivity margin for burnup is compensated by the addition of boric acid to the coolant, the possibilities of influencing the energy release field are very limited.

The international application WO 2020/224764 proposes a method for controlling a PWR type reactor, in which the operation algorithm of the reactor power influencing elements (absorbing rods, boric acid solution injection) is calculated based on the load schedule provided by the dispatcher for 24 hours in advance and a number of restrictions on the reactor parameters ( minimizing the movements of the absorbing rods, maintaining the required value of the axial offset, minimizing the consumption of boric acid and distillate, burnout compensation, burnout leveling, etc.). Directly during the operation of the reactor, several options for influencing the reactor with the help of controls are calculated, from which the optimal one is selected from the point of view of satisfying the selected criteria. This patent can be considered as a patent analogue.

This method of controlling the reactor makes it possible to control, among other things, the energy release field. In the patent under consideration, the algorithm for moving absorbing rods is calculated in real time. This is due to the fact that thermal neutron reactors, in particular PWR type, are characterized by the phenomenon of poisoning, which has complex temporal (iodine well) and spatial (xenon waves) dependencies and is determined by the history of reactor power changes over the past few days. Therefore, it is impossible to calculate the optimal immersion profile of absorbing rods for a thermal neutron reactor in advance at the design stage.

The main disadvantages of the technical solution proposed in the patent analogue are as follows:

1. The formation of the energy release field cannot be ensured in the best way, since at the same time other equally important tasks must be solved by moving the absorbing rods: providing a negative offset value to eliminate the heat transfer crisis and compensation for xenon fluctuations in the distribution of the neutron flux, and, consequently, the energy release. These requirements may be in conflict with each other.

Xenon fluctuations in RBMK reactors before the introduction of local automatic power controllers when the reactor was operating at constant power required constant operator work. There are no local automatic power controllers in PWR/VVER reactors.

2. The results of on-line calculations of various functionals are updated with a frequency of 200 milliseconds, which necessitates the use of simplified calculation algorithms and excludes the possibility of using the most accurate calculation methods with a large amount of machine time even when using off-line calculations at the design stage.

3. In the case of long-term operation of the PWR/VVER reactor at constant power, the drop in reactivity as a result of burnup, leading to a mismatch between the specified and actual power (decrease in the average coolant temperature or steam pressure in the steam collector), does not cause a change in the position of the CV, which can be removed by differently, controlling the energy release field, but issues a request to reduce the concentration of boric acid, which does not allow controlling the energy release field.

4. The technical solution proposed in the patent under consideration is not applicable to fast reactors, in which there are no xenon effects, and the drop in reactivity as a result of burnup is compensated by removing the absorbing rods from the maximum submerged state at the beginning of the campaign until the rods are completely removed from the core at the end of the campaign, which allows effectively manage the energy release field.

5. The analogue patent also does not describe the technical algorithm for implementing the technical solution proposed in the patent.

In the technical solution proposed in the application, applicable in fast neutron reactors, in which there is no poisoning, the entire reactivity margin for burnup is compensated by absorbing rods, there are no requirements to provide the necessary offset, which are necessary in water-cooled reactors due to the possibility of a heat removal crisis, these patent shortcomings are there are no analogues. Therefore, at the design stage of the reactor, it is possible to most accurately calculate the optimal position of the absorbing rods for each moment of the campaign, determined only by power generation, depending only on fuel burnup, giving for each moment of the fuel campaign the position of the PS, providing the optimal profile of the energy release field, ensuring the maximum possible alignment of the temperature field coolant at the exit from the core, and put it at the design stage in the algorithm and hardware solution of the automatic control system.

Accepted abbreviations

A3 - emergency protection

NFCM - neutron flux control equipment

ARM - automatic power regulator

BS - comparison unit

DP - position sensor

DUM - power level sensor

ЗМ - power adjuster

IM - actuator

IP - period meter

KS - compensating rod

MKUM - minimum controlled power level

NKV - lower limit switch

PPR - planned - preventive maintenance

PS - absorbing rod

PUUS - program control device

C - selector

SU3 control and protection system

SE - energy production meter

E - reactor power generation

YaR - nuclear reactor

Disclosure of invention

The problem, the solution of which is provided by the implementation of the claimed method and device, is to increase the power of the reactor without increasing the flow rate of the coolant.

The technical result consists in increasing the average coolant temperature at the core outlet and, accordingly, the possibility of increasing the reactor power without increasing the coolant flow rate, by providing dynamic profiling of the energy release field during the campaign to reduce the unevenness of the coolant temperature field at the core outlet. Another technical result, while maintaining the reactor power and the duration of the campaign, achieved by leveling the energy release field while maintaining the average temperature of the coolant at the exit from the core, is the possibility of reducing the maximum temperature of the fuel cladding, which increases reliability and safety.

The specified technical result is achieved by the fact that the method of automatic control of the power of a fast neutron nuclear reactor by moving the absorbing rods of the automatic power controller includes:

- preliminary calculation at the design stage of the positions of the absorbing rods, which ensure the formation of the optimal energy release field for each moment of the campaign (energy generation);

- loading into the memory of the program control device (PCD) according to the results of the program calculations with the sequence of extracting the absorbing rods from the core to positions corresponding to the optimal distribution of the power release field along the radius of the core for a given value of power generation;

- turning on the automatic power controller (AWC) to change the position of the absorbing rods in one direction or the other according to the signal generated in the comparison unit as the difference between the signals coming into it from the power setting device and the power level sensor, and in starting modes as the difference between the signals of the specified and the actual period of the reactor coming from the period meter, while the signals to the power level sensor and the period meter come from the neutron flux control equipment (NFCM);

- bringing the reactor to a given energy level of power with the profile of immersion of the absorbing rods, ensuring the optimal distribution of the energy release field, by automatically, in accordance with a given sequence stored in the memory of the CPMS, extracting the absorbing rods from the core to positions that ensure the minimum non-uniformity of the coolant temperature field on exit from the core for a given value of power generation, which are stored in the memory of the CPMS based on the results of pre-calculations, while the movement of the absorbing rods is carried out by the actuating mechanisms of the absorbing rods;

- SS by means of the SS actuators, the power supply to which is supplied through the SS selection selector, is automatically moved in the active zone in a given sequence stored in the PUUS memory, in certain small steps, the value of which does not distort the required SS immersion profile, and, accordingly, the energy release field, when limiting the period of the reactor by the value specified in the comparison unit (BS), to the positions until the reactor reaches the critical state at the minimum controllable power level (MCL). The extraction of the PS is terminated when the CPSS receives a signal from the comparison unit that the set value of the minimum controlled power level has been reached, which is then maintained in automatic mode;

- then the power of the reactor at the operator's command is increased from MKUM to a level corresponding to the beginning of the energy range specified in the PUUS (about 3-5% N _nom ). At the same time, power is supplied to the PS IM operating in the AWP mode, according to the imbalance signal between the set and actual power levels coming from the BS. The IM extracts this PS by introducing positive reactivity into the reactor, which ensures the period of increase in the reactor power specified in the CPMS, after which its IM is automatically turned off;

- when the actual power level approaches the set value and the beginning of the action of negative feedbacks that slow down the rate of power increase (increase in the period of the reactor), according to the signal of the imbalance between the set and actual values of the period coming from the BS, the PS with its IM, the power supply to which is supplied through the selector selection of the PS, are automatically removed from the core in a given sequence, embedded in the CPMS, in small steps, compensating for the negative power effect of reactivity, to positions until the reactor reaches the power level specified by the power master (PM), further supported automatically by the last PS operating in the mode workstation;

- then, with the turbine plant prepared for operation, the reactor is transferred by the power adjuster to the required energy power level, which is maintained automatically, while as the fuel burns out, the PS in accordance with the program stored in the PUUS memory are removed in a given sequence to positions that provide the optimal shape of the field energy release (maximum equalization of the coolant temperature field at the exit from the core) for each moment of power generation, the corresponding signal about the current value of which is fed to the CPMS from the power generation meter (SE).

The technical result is also achieved by the fact that in the automatic power control system of a nuclear reactor, including absorbing rods that affect reactivity, with actuators, each of which can perform the functions of an automatic power controller, a compensating rod and an emergency protection rod, neutron flux control equipment, equipment a control that generates warning and alarm signals for a change in the position of the absorbing rods, sensors and indicators of the positions of the absorbing rods, a power adjuster, a power level sensor, a reactor period meter, a comparison unit that generates a signal applied to the actuator that affects the movement of the absorbing rods, a counter energy generation, absorber rod position sensors, the control equipment for absorber rods includes a control program device that receives a signal from a power level sensor, an energy production counter, and PS position sensors, and transfers the function of an automatic power controller from one absorber rod to another absorber via the PS selection selector. the rod in such a way that the movement of the absorbing rods during the campaign occurs with the formation of a certain profile of the immersion of the system of absorbing rods in accordance with the sequence and the step of moving the absorbing rods embedded in the program-control device.

The implementation of the proposed method using the proposed device makes it possible to reduce the non-uniformity of the coolant temperature field at the core outlet, which makes it possible to increase the average coolant temperature at the core outlet and, accordingly, increase the reactor power, without increasing the coolant flow in the primary circuit and exceeding the maximum allowable fuel cladding temperatures. The proposed invention also makes it possible to unload the operator from performing many responsible manual operations to control the nuclear reactor, which eliminates the influence of the human factor on safety.

The claimed invention is illustrated in the drawing (Figure 1), which shows a block diagram of a variant of a possible implementation of the device.

Implementation of the invention

The automatic power control system of a nuclear reactor contains absorbing rods 1 that affect reactivity, with actuators 2, each of which can perform the functions of an automatic power controller, a compensating rod and an emergency protection rod, neutron flux control equipment 3, control equipment that generates warning and emergency signals to change the position of absorbing rods 1, position sensors of absorbing rods 4, power sensor 5, power level sensor 6, reactor period meter 7, comparison unit 8, which generates a signal applied to the actuator 2 that affects the movement of absorbing rods 1, counter energy generation 9, the equipment for controlling the absorbing rods includes a program-control device 10, which receives a signal from the power level sensor 6, the energy output counter 9, and the position sensors of the absorbing rods 4, and transmits the function of the automatic power regulator from one absorbing rod 1 through the rod selection selector 11 to another absorbing rod 1 in such a way that the movement of absorbing rods 1 during the campaign occurs with the formation of a certain profile of immersion of the system of absorbing rods 1 in accordance with the sequence and step of movement of absorbing rods 1 embedded in the control program device 10.

In the proposed CPS, all PS 1 participate in the automatic program control mode, sequentially performing the function of automatically changing and maintaining a given power level. The signal to turn on the actuator 2 PS 1, which performs the function of an AWP, to change its position in one direction or another is formed in the comparison unit (BS) 8 as the difference between the signals coming into it from the power master (PM) and the power level sensor (DUM), and in starting modes as the difference between the signals of the specified and actual period of the reactor coming from the period meter (PI). The signals to the DUM and IP come from the neutron flux control equipment (NFCM). PS 1 during the campaign move according to the sequence specified in the program-control device (PUUS) to the appropriate positions that provide the best shape of the energy release field.

To do this, the PS, located at different radii, when the reactor is operating at the power energy level, move in the core in such a way that at each moment of the campaign at a given power level, their position in the core, predetermined by calculation, would provide the optimal shape of the energy release field.

Before implementing the proposed method for dynamic control of the energy release field, the reactor must be brought to a given energy power level with the submersion profile PS 1, which ensures the optimal shape of the energy release field.

Below, as an example, one of the possible programs for such reaching a given energy power level is considered.

It is carried out using well-known software, for example, the REACTOR application package (O.G. Komlev, N.N. Novikova, M.M. Trevgoda, E.V. Filimonov, “Status and problems of calculation and methodological support for the design development of reactor plants with lead-bismuth coolant", Bulletin of Higher Educational Institutions. Nuclear Power Engineering. 2007, No. 1, pp. 79-91) calculation of the positions of absorbing rods that ensure the alignment of the energy release field.

According to the results of calculations, the program with the sequence of extracting the absorbing rods from the active zone to the positions corresponding to the optimal distribution of the energy release field for a given value of power generation is loaded into the CPMS memory.

Carry out the launch of the reactor.

The first stage of start-up begins from the initial muffled state of the reactor, when all PS 1 are on the lower limit switches (NKV), at the command "platoon AZ", according to which the windings of electromagnets IM 2, holding PS 1 in a predetermined position, are supplied with power. Further, SS 1 sequentially according to the program stored in the memory of the PUUS 10, with their IM 2, which are powered through the selector (C) of choice 13 of the SS 1, are automatically removed from the active zone by the same values to the “even” position, providing the subcriticality necessary for safety in accordance with the requirements of regulatory and technical documents. This position of PS 1, stored in the memory of PUUS 10, is determined in advance by calculation and must be confirmed experimentally during the first start-up of the reactor with a fresh fuel load.

The second stage of the start-up begins at the command "Profile", according to which PS 1 with its IM 2, the power supply to which is supplied through the selector (C) of choice 13 of PS 1, automatically according to the sequence specified in the program, embedded in the memory of the PUUS 10, are removed or immersed in the active the zone into positions corresponding to the optimal form of the energy release field for a given value of power generation, which are stored in the memory of the PUUS 10 based on the results of calculations.

In this case, the necessary subcriticality is ensured due to the fact that the positive reactivity released by the recoverable PS 1 is compensated by the negative reactivity introduced by the submersible PS 1.

If the reactor plant is equipped with a system for in-reactor monitoring of the coolant temperature field at the core exit, then during the first campaign during annual shutdowns, it is possible to correct the submergence profile of PS 1 for a given value of power generation according to the actual values of coolant temperatures at the core exit, ensuring their equalization . In this case, the algorithm of the second stage of the launch "Profile" is used.

The third stage of the launch begins after the completion of the second stage by the command "Physical launch". At the same time, PS 1 with its IM 2, the power supply to which is supplied through the selector (C) of choice 13 of PS 1, is automatically removed from the active zone according to the sequence specified in the program, stored in the memory of the PUUS 10, in small steps (for example, one percent of the full stroke of the PS ) when the reactor period is limited by the value specified in BS 8 to positions until the reactor reaches the critical state at the minimum controllable power level (MCL). Extraction of PS 1 is terminated when the CPUS 10 receives a signal from the comparison unit (BS) 8 to reach the predetermined value of the MCM, which is then maintained in automatic mode. This concludes the third stage of the launch.

The maximum speed of SS 1 movement must be hardware-limited to a value that provides the required quality of maintaining a given power level and the quality of transients in the AWP mode when using the weakest SS 1, almost completely submerged or removed from the core, and satisfy the requirements of regulatory documentation.

The fourth stage of the start-up begins when the reactor and turbine-generator units are ready for operation by the command "Preparation for power start-up". According to this command, according to the signal of the imbalance between the actual and the specified period of the reactor, coming from the BS 8, the PS 1, operating in the AWP mode on the MCCM, is removed from the core by an amount that provides the specified period of the reactor, after which its IM 2 is automatically turned off. If this PS 1 cannot provide the specified period at the step provided for in the CS 10, the control automatically switches to the next PS 1 according to the program embedded in the CS 10. In this case, the power level begins to grow, passing through several orders, maintaining the specified period, up to achieving a power level of 3-5% N _nom . When approaching this power level, set in CPSS 10, negative temperature/power feedback begins to operate, reducing the introduced positive reactivity. In this case, PS 1, which is in the AWP mode, on a signal to IM 2 from BS 8, stabilizes the power at a given value.

The fifth and last stage of the launch, upon completion of which the proposed method of dynamic control of the energy release field is implemented, begins at the command "Energostart". According to this command, when the reactor and turbine plants are prepared for operation, according to the imbalance signal between the set and actual power levels coming from BS 8, PS 1 with their IM 2, the power supply to which is supplied through the selector (C) of choice 13 of PS 1, are automatically removed from the active zones according to the sequence specified in the program, embedded in CPMS 10, in small steps (for example, one percent of the full stroke of the PS), compensating for the negative power effect of reactivity, to the positions until the reactor reaches the energy power level specified by ZM 5, then maintained automatically. In this case, the rate of change of the preset power of the reactor supplied to the BS 8 must correspond to the value specified by the design, which is ensured by the corresponding device of the power adjuster 5, in which the abrupt change in the preset power level is converted into a time-stretched change corresponding to the rate of change of power incorporated in the design. This ends the energy start and begins operation at a constant set power level.

At this power level, the last PS 1 operating in the AWP mode, the extraction of which brought the reactor to a given power level, is slowly removed from the core, compensating for the loss of reactivity from burnup, accumulation of fission products and other processes of changing the nuclide composition, depending only on power generation (E ) of the reactor.

The step of extracting each PS 1 operating in the AWS mode, before transferring automatic control to the next PS 1, is determined by the new profile of submersion of PS 1 into the active zone specified in the memory of the PUUS 10 for each interval of power generation ΔE _i . The interval for power generation, through which the profiles of submersion of PS _k into the core - h _m (N,E) are set in the memory of PUUS 10, is selected according to the results of calculations so that the relative profiles of submersion of PS 1 for E _i and E _{i +1} would differ slightly . From the value of the power level of the reactor N _n the relative profile of the subsidence of PS 1 for a given value of power generation E _i is practically independent. The signal in the CPUS 10 about the extraction of this PS 1 to the position h _m , according to which the command is generated in the CPUS 10 to transfer automatic control to the next PS 1, enters the CPUS 10 from the position sensor (DP) 5 of the absorbing rod 1, placed in the IM 2 of each PS 1. After the end of work in the AWP mode of the last PS 1, the cycle is repeated for the next interval of power generation, if the set power level does not change.

In the event of a change in the set power level, the PS 1 with its IM 2, the power supply to which is supplied through the selector 13 of the PS 1, according to the imbalance signal between the new set and actual power levels coming from the BS 8, are automatically removed or immersed in the active zone according to the specified the sequence program laid down in the CPMS 10, in small steps (for example, one percent of the full stroke of the PS), compensating for the power effect of reactivity, to the positions until the reactor reaches a new power level, set by ZM 5, then maintained automatically. In this case, the rate of change in the reactor power must correspond to the value specified by the design, which is ensured by the corresponding power setting device.

Since all the substations are included in the automatic control loop of the substation in the proposed method, in the event of extremely unlikely, but fundamentally possible initiating events (multiple simultaneous failures in the CPS, malicious actions), a continuous uncontrolled removal of the substation from the core (“self-propelled” rods) can occur with the release of a large positive reactivity.

In a CPS with an independent group of AE rods, such a "self-propelled" absorber rods can cause a reactor runaway on prompt neutrons, since the efficiency of an independent AE system is usually much lower than the total reactivity margin at all PS.

This will not happen in the proposed CPS, because according to the signals of emergency protection against exceeding the set power level, reducing the period of the reactor below the set value or exceeding the set value of the coolant temperature, which cannot be blocked from the control panel, or other AZ signals, the windings of the holding electromagnets of all MIs are de-energized. PS. As a result, the “self-propelled” SS will stop, since all the rods perform the function of the AZ and, when the windings of the holding electromagnets are de-energized, will fall into the active zone on the NKV.

To improve the reliability of the AP operation, all electrical circuits and AP devices of all IMs of the PS can be divided into two independent groups that ensure the performance of the AP functions in the event of a failure of one of the groups.

Claims (9)

1. A method for controlling and protecting a fast neutron nuclear reactor by moving the absorbing rods of an automatic power controller, including: - calculation of the positions of the absorbing rods, providing the optimal shape of the energy release field for each moment of the campaign (energy generation); - loading into the memory of the program-control device according to the results of calculations of the program with the sequence of movement, including the extraction and immersion of the absorbing rods into the core into positions corresponding to the optimal shape of the energy release field for a given value of power generation; - turning on the automatic power controller to change the position of the absorbing rods in one direction or another according to the signal generated in the comparison unit as the difference between the signals coming into it from the power setting device and the power level sensor, and in starting modes as the difference between the signals of the specified and actual doubling periods the neutron power of the reactor coming from the period meter, while the signals to the power level sensor and the period meter come from the neutron flux control equipment; - bringing the reactor to a given energy level of power with an insertion profile of the absorbing rods that ensures the optimal shape of the energy release field, by automatically, in accordance with a given sequence stored in the memory of the program-control device, extracting or immersing the absorbing rods into the core into positions corresponding to the optimal the distribution of energy release in the core for a given value of power generation, which are stored in the memory of the program-control device according to the results of calculations, while the movement of the absorber rods is carried out by the actuating mechanisms of the absorber rods, the power supply to which is supplied through the selector of their choice; - in the reactor start-up mode, absorbing rods are automatically removed from the core in a given sequence stored in the memory of the program-control device by means of actuating mechanisms of absorbing rods, which are powered through the selection selector, in small steps, while limiting the period of the reactor by the value set in the comparison unit in the position before the reactor reaches the critical state at the minimum controlled power level, the extraction of the absorbing rods is stopped when the control program receives a signal from the comparison unit about reaching the set value of the minimum controlled power level, which is then maintained automatically; - according to the signal of the imbalance between the actual and specified periods of the reactor, coming from the comparison unit, the absorbing rod, operating in the automatic power controller mode at the minimum controlled power level, is removed from the core by an amount that provides the specified period of the reactor, after which its actuator automatically turn off; - according to the imbalance signal between the set and actual power levels coming from the comparison unit, the absorbing rod is automatically removed from the active zone by its actuators, which are powered through the selector for selecting absorbing rods, according to a given sequence embedded in the program-control device, in certain steps , compensating the power effect of reactivity, to the positions until the reactor reaches the power level set by the power controller, which is then maintained automatically. 2. The control and protection system of a fast neutron nuclear reactor, including absorbing rods that affect reactivity, with actuators, each of which performs the functions of an automatic power controller, a compensating rod and an emergency protection rod, neutron flux control equipment, control equipment that generates warning and alarms for changing the position of the absorbing rods, sensors and position indicators of the absorbing rods, a power setting device, a power level sensor, a reactor period meter, a comparison unit that generates a signal applied to the actuator that affects the movement of the absorbing rods, a power output meter, a position sensor absorber rod, characterized in that the control equipment of the absorber rods includes a software control device that receives a signal from a power level sensor, an energy production counter and a position sensor, and transmits the function of automatic power control from one absorber rod to another absorber rod through the absorber rod selection selector so that the movement of the absorbing rod during the campaign occurs with the formation of a certain profile of the immersion of the system of absorbing rods in accordance with the sequence and step of moving the absorbing rods embedded in the program-control device.

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