RU2458415C1 - Protection method of vver reactor core as to reactor power overshoot and power change rate using readings of background in-core detectors - Google Patents

Abstract

FIELD: power industry.

SUBSTANCE: monitoring of fulfilment of design restrictions of reactor operating conditions is performed by means of detectors of neutron flux monitoring equipment located outside the reactor housing and a set of in-core detectors related to in-core monitoring system, emergency protection, automated workstation, and a set of detectors outside the reactor, which are related to automated workstation emergency protection, and actuation of reactor power level control systems and/or reactor emergency protection systems is initiated. Additional connection is formed between background detectors included in DCS and automated workstation emergency protection by means of additionally introduced control module.

EFFECT: enlarging physical range of detectors meant for local physical control of power and reactor protection level.

8 cl, 1 dwg

Description

The invention relates to nuclear energy, in particular, to research of the thermal conditions of the active zones of nuclear reactors, for example, during operation of a VVER-type nuclear reactor (Water-to-water power reactor), intra-reactor control systems to provide control over the energy release field in a VVER-type reactor, and can be used in nuclear energy in calculating core power, reactivity (power change over time) and as an additional signal for activating core protection (to expand I am the physical variety of independent signals to protect).

Abbreviations Used:

RBMK is a high-power channel reactor.

KEDN - Compton emission neutron detectors.

VVER - water-water power reactor

AKNP - neutron flux control equipment.

AZ AWP - emergency protection, automatic power regulator.

OR CPS - regulatory bodies of the control and protection system.

DPZ - direct charge detector.

SVRK - system of internal reactor control.

PZ1 - preventive protection of the first kind.

PZ2 - preventive protection of the second kind.

AZ - emergency protection.

A technical solution is known according to RF Patent 2310248, IPC G21C 17/00, System for monitoring the neutron flux of a nuclear reactor,

used at the RBMK reactor (high power reactor, channel) and at the VVER reactor.

The present invention relates to the field of neutron flux control for providing control, control and protection of tank nuclear reactors.

The disadvantages of this solution according to RF Patent 2310248 are the fundamentally low neutron sensitivity, which forces to increase the size of the QED, reduces the number of QED in the assembly, but, nevertheless, does not allow for a sufficiently accurate correction for the current of the communication line and creates known difficulties when recording and control equipment.

The technical solution is also known: VVER-1000 reactor:

See “Technological scheme of power units with VVER440 and VVER1000 reactors

The main structural characteristics of the VVER-1000 core.

olav-smt.narod.ru/firm/reactor.htm

The specified solution can be considered as a prototype to the declared.

The disadvantages of this known solution is also low neutron sensitivity, insufficiently accurate corrections for the current of the communication line, which creates known difficulties in the operation of recording and control equipment.

The technical problem of the proposed method is to expand the physical diversity of many detectors designed for local automatic control of the power level and reactor protection by attracting (formation of additional links) background detectors, which are inertia-free gamma-detectors, which will ensure maximum reliability of information on the distribution of the energy release field in the active zone of the reactor, the safety of operation of the reactor installation and, accordingly, will be Vova improve economic operation of the reactor characteristics.

The solution to this technical problem is provided by the proposed set of essential features set forth below

namely:

A method of protecting the VVER reactor core by exceeding the power and rate of change of reactor power using the readings of background in-reactor detectors that are part of the RPD, which consists in monitoring compliance with the design restrictions of the reactor operating conditions by means of AKNP, which includes the SVRK, located outside the reactor vessel, and a set of in-reactor detectors associated with the ICS contained in the reactor of the control module of the automated workstation, and a set of non-reactor detectors associated with the automatic control system and initiate t triggering systems for regulating the power level of the reactor (OR CPS) and / or emergency reactor protection systems (AZ),

moreover

form an additional connection between the background detectors that are part of the DPS and the automated workstation through the introduction of an additional control module,

wherein

- when forming an additional connection, additionally measure reliable currents of background veins, inertialess and proportional capacities of the reactor core;

- when forming an additional connection, calibration of background detectors is additionally performed.

- when forming an additional connection, an additional change is revealed in the total signal of the background core of the DPZ in time;

- when forming an additional connection, an additional value is preliminarily determined and set for the setpoint for exceeding the absolute power to initiate the actuation of systems controlling the power level of the reactor (OR CPS);

- when forming an additional connection, the setting is additionally preliminarily determined and set according to the rate of change of power (acceleration period) to initiate the actuation of control systems by the power level of the reactor (OR CPS);

- when forming an additional connection, an additional value is preliminarily determined and set for the setpoint for exceeding the absolute power to initiate the operation of emergency reactor protection systems (AZ);

- when forming an additional connection, the setting is additionally preliminarily determined and set according to the rate of change of power (acceleration period) to initiate the operation of emergency reactor protection systems (AZ).

The proposed solution is illustrated graphically.

In the figure, the positions indicated:

1 - VVER case.

2 - communication line AKNP with the control module (AZ AWP) OR CPS.

3 - AKNP sensors.

4 - sensors (DPZ and background) SVRK.

5 - VVER core.

6 - communication line of the control module with the OS CPS.

7 - communication lines of intra-reactor sensors with IMSS.

8 - communication line of the background detectors with the control module (AZ AWP) OR CPS.

9 - additional control module.

10 - OR CPS.

Description of the essence of the proposed invention.

A nuclear reactor, as an object of control, is characterized by a large number of various interrelated physical quantities, and some of them are distributed in space (field) quantities. One of the most complex and most important tasks is to obtain reliable and independent signals for triggering PZ1 (preventive protection of the first kind), PZ2 (preventive protection of the second kind) and AZ (emergency protection). The greater the physical diversity of these signals, the safer this reactor installation. This task is important both for ensuring the safe operation of the reactor installation, and for improving the economic characteristics of operation.

At present, the monitoring of compliance with design restrictions is assigned to the in-reactor sensors of DPZ (neutron-sensitive detectors of direct charge) and TP (thermocouples, resistance thermometers) and AKNP (equipment for monitoring the neutron flux) located behind the reactor vessel.

It is proposed to supplement this set of sensors with an already physically existing set of background sensors (background sensors - detectors - are part of the DPS, and at present their functionality consists only in highlighting the useful, activation, metrologically determined signal of neutron-sensitive sensors), while the number of background sensors equal to the number of overpressure in the reactor core. A significant advantage of background sensors is their presence in the reactor core (unlike ACNP) and their inertia-free response to any change in the core power speed (in contrast to DCR, where the instantaneous component of the signal is now allocated in hardware).

The proposed method for determining the power of fuel assemblies in the locations of neutron detectors, power and reactivity (acceleration period) of the core during operation of the VVER reactor includes the following operations:

- using the equipment of the in-reactor monitoring system, reliable background currents, inertia-free and proportional powers of the reactor core are measured (analog 1 is suitable for the functions, prototype: Reactor protection by AKNP (neutron flux monitoring equipment);

- calibration is performed (the coefficients of the transition from the background detector current to the fuel assembly power and from the sum of the background detector currents to the core power are determined (analog 1 is suitable for the functions, prototype: Reactor protection by AKNP (neutron flux monitoring equipment);

- to change the total signal of the background conductors of the overcurrent protection circuit in time using the equipment of the internal reactor control system and predetermined settings for exceeding the absolute power, the rate of change of power (acceleration period), a hardware decision is made on the operation of the systems for controlling the power level of the reactor (OR CPS) and if necessary reactor protection (AZ) (prototype is suitable for the functions: Reactor protection according to AKNP (neutron flux control equipment).

The proposed method differs from the known possibility of the most reliable determination of the rate of change (acceleration period) of the power of the reactor core during operation of the VVER reactor.

Thus, when determining the power of the reactor core, the rate of change of power, it is proposed to supplement the already existing set of in-reactor and non-reactor detectors with background detectors that are part of the RPD, giving them (background detectors) additional functions (namely, they additionally monitor compliance with design restrictions of the conditions operation of the reactor by means of background detectors included in the DPZ), which will ensure maximum reliability of information on the volume and time distribution over I energy release in the reactor core, the safe operation of the reactor plant and, accordingly, will help improve the operation of the reactor economic performance.

Clarifications to the above:

- signs: "... a gamma-sensitive detector ..."

should be understood as:

"... a gamma-sensitive detector, the readings of which linearly and without inertia depend on the power of the fuel assembly (fuel assembly) in which it is located ...";

- signs:

"... the period of dispersal ..." should be understood as:

"... time to double power ...".

Information sources

1. RF patent 2310248, IPC G21C 17/00 “SYSTEM OF CONTROL OF NEUTRON STREAM OF NUCLEAR REACTOR”, Use in “RBMK Channel Nuclear Power Reactor. Moscow, publishing house "GUP NIKIET", 2006 (analogue).

2. Prototype: protection of the core of the VVER reactor according to local parameters using the readings of in-reactor neutron detectors, see the VVER-1000 reactor:

See “Technological scheme of power units with VVER440 and VVER1000 reactors

The main structural characteristics of the VVER-1000 core.

olav-smt.narod.ru/firm/reactor.htm.

Claims (8)

1. The method of protecting the VVER reactor core by exceeding the power and the rate of change of the reactor power using the readings of the background in-reactor detectors included in the RPD, which consists in monitoring compliance with the design restrictions of the reactor operating conditions by means of AKNP located outside the reactor vessel, including IWRM, and a set of in-reactor detectors associated with IWRM, which is contained in the reactor of the AP ARM control module, and a set of non-reactor detectors associated with ASW, and initiating by triggering the power level of the reactor control systems (control rod) and / or safety systems of the reactor (AZ), characterized in that the additional bond formed between the members of the DPC background detectors and AZ APM through the introduction of additional control module. 2. The method according to claim 1, characterized in that when forming an additional connection, reliable currents of the background conductors, inertialess and proportional powers of the reactor core are additionally measured. 3. The method according to claim 1, characterized in that when forming an additional connection, calibration of background detectors is additionally performed. 4. The method according to claim 1, characterized in that when forming an additional connection, a change in the total signal of the background conductors of the overcurrent protection in time is additionally detected. 5. The method according to claim 1, characterized in that when forming an additional connection, an additional setting is preliminarily determined and set for exceeding the absolute power to initiate the actuation of the control systems by the reactor power level (RMS CPS). 6. The method according to claim 1, characterized in that when forming an additional connection, a setting is additionally preliminarily determined and set according to the rate of change of power (acceleration period) to initiate the actuation of systems controlling the power level of the reactor (OR CPS). 7. The method according to claim 1, characterized in that when forming an additional connection, an additional setting is preliminarily determined and set to exceed the absolute power for initiating the operation of reactor emergency protection (AZ) systems. 8. The method according to claim 1, characterized in that when forming an additional connection, the setting is additionally preliminarily determined and set according to the rate of change of power (acceleration period) to initiate the operation of reactor emergency protection (AZ) systems.