RU2231144C2 - Nuclear reactor emergency cooling device - Google Patents

Abstract

FIELD: nuclear power engineering; emergency cooling of reactor in case of rupture in liquid coolant pipeline running to reactor.

SUBSTANCE: device has reactor coolant circulating circuit incorporating coolant supply pipelines running to reactor, closed supply lines, group headers for coolant dispensing among process channels holding fuel elements, group headers for accumulating coolant discharged from process channels, coolant discharge closed lines and pipelines, check valves and gate valves, emergency water storage tanks communicating through pipelines with coolant circulating circuit, and water makeup system for emergency water storage tanks; in addition it has check valves disposed at inlets of headers for coolant dispensing from closed supply line halved by means of closed gate valves and also at inlets of coolant circulating circuit from water supply pipelines running from emergency water storage tanks.

EFFECT: enhanced reliability and speed of response to emergency situations.

1 cl, 1 dwg

Description

The invention relates to nuclear energy and can be used for emergency cooling of nuclear reactors when ruptured pipelines leading the liquid cooler into the reactor.

A device for emergency cooling of a nuclear reactor [US 4181570, G 21 C 15/18, 1980] is known, including pipelines for supplying cooling water to the reactor, pipelines for draining water from the reactor, valves, containers for storing emergency water supplies, and a system for feeding containers with water. If one of the pipelines for supplying cooling water to the reactor breaks from the emergency storage tank, the water must flow directly into the reactor core. The disadvantage of this device is that the water from the tank will tend to fall into the gap, bypassing the active zone, since after a pipeline rupture occurs, the rupture site does not cut off and at the rupture point the water pressure drops to the ambient pressure value, which will be lower than the pressure in the reactor due to heating of the active zone by residual energy release and an increase in the vapor pressure of the boiling coolant caused by a violation of normal heat removal. Which ultimately leads to overheating and damage to the elements of the reactor core.

It is also known a device for cooling a nuclear reactor [RU 2150757 C1, IPC 7 G 21 C 15/18, 2000], taken as a prototype, including pipelines for supplying cooling water to the reactor, pipes for draining water from the reactor with attached containers for storing emergency water supplies , a system for feeding containers with water, check valves and gate valves.

In case of an accident with a significant rupture of the pipeline for supplying the coolant to the reactor in the prototype, a valve actuator installed on the pipeline connecting the tanks to the emergency water supply and the coolant supply point to the active zone is given a signal to open the valve to supply water to the active zone from the tanks. The disadvantage of this device is that it takes time to determine the location of the gap and to open the valve. In addition, a failure may occur in the electrical circuits of the signal, and the valve will not open, which will make the device inoperative.

The objective of the invention is to increase the reliability and speed of inclusion of the emergency cooling device of a nuclear reactor in case of rupture of pipelines for supplying coolant to the reactor.

The problem is solved in that the emergency cooling device for a nuclear reactor, including a coolant circulation circuit through the reactor, containing pipelines for supplying coolant to the reactor, group collectors for distributing coolant through technological channels with heat-generating elements, group collectors for collecting coolant from technological channels, pipelines for removing coolant from the reactor , check valves and gate valves, tanks for storing emergency water supplies, connected by pipelines to the circuit m of coolant circulation, a system for feeding containers with water, contains a closed supply communication and additionally check valves located at the entrances to the distributors of the coolant from the closed supply communication divided into two parts by closed valves of the coolant, as well as at the entrances to the coolant circulation circuit from the pipelines for supplying water from the tanks for storing emergency water supplies.

The dimensions and number of check valves installed at the inlets to the coolant circulation circuit from the water supply pipelines from the tanks for storing emergency stocks are determined based on the possibility of supplying such a quantity of water from the tanks to the circuit that compensates for the leakage of the coolant into the gap. They are determined by calculation taking into account hydraulic losses, checked and refined during commissioning.

The essence of the proposed design of a device for emergency cooling of a nuclear reactor is shown in the drawing.

In conditions of normal operation of the reactor through the supply pipelines 1, the coolant enters the closed supply communication 2, then to the group distribution manifolds 3 through the technological channels 4 with fuel elements, where the coolant is heated. Then, from the technological channels, the coolant enters the group collectors for collecting the coolant 5, then into the closed communication 6 and pipelines for removing the coolant 7 from the reactor. To compensate for changes in the volume of the coolant in the circulation circuit caused by changes in the temperature of the coolant due to changes in the reactor, containers of the circuit 8 are used, partially filled with water under gas pressure, which is held by the compressors 9. To feed the coolant to the circulation circuit, make-up pumps are used 10. The circulation of the coolant in the circuit is provided by the operation of the main circulation pumps 11L and 11R. To perform the repair of the circulation circuit, the shut-off reactor has valves 12. The valves shown as darkened are closed and, accordingly, the darkened valves are open. Non-return valves 13 are also installed in the circulation circuit. Steam generators are used to remove heat from the heat carrier heated in the reactor. water 17. The device further comprises check valves 13L, 13R and 13C. Valves 13L and 13R are installed at the entrances to the heat-transfer distribution manifolds from a closed supply communication divided into two parts by closed gate valves, and the valves 13C are installed at the entrances to the coolant circulation circuit from the water supply pipelines from the tanks 15 for storing emergency water supply.

To ensure heat removal from the reactor in emergency conditions caused by an emergency rupture of one of the supply pipelines 1 of the circulation circuit, part of the valves 12 of the coolant circuit are closed.

In the event of an emergency rupture, for example, in section AA of the pressure pipe 1 of the coolant circulation circuit, the coolant flows into the gap from the emergency part of the closed supply line 2 highlighted by closed valves, and the non-return valves 13R are closed and the emergency coolant outflow to the gap from the side of the reactor stops . The main circulation pumps 11L supply the coolant through the check valves 13L to the collectors 3 and then to the process channels 4, thereby removing heat from the fuel elements located in the channels. In the event that the emergency rupture in section AA has a very large surface area of the circuit depressurization, and the water supply in tanks 8 and the capacity of the pumps 10 is insufficient to compensate for the coolant leakage into the gap, and the pressure at the inlet to the main circulation pumps 11L and 11R drops to values that are lower than the hydrostatic pressure of the water created by the water level in the tanks 15, the check valves 13C open and the water from the tanks 15 enters the circulation circuit, providing complete compensation for the water lost in the gap. This ensures reliable cooling of the reactor.

Claims (1)

A device for emergency cooling of a nuclear reactor, including a coolant circulation loop through a reactor, containing pipelines for supplying coolant to the reactor, group collectors for distributing coolant through technological channels with heat-generating elements, group collectors for collecting coolant from technological channels, closed communication, pipelines for removing coolant from the reactor, check valves and valves, tanks for storing emergency water supplies, connected by pipelines to the circulation circuit a heat transfer medium, a system for feeding containers with water, characterized in that the device comprises a closed supply communication and additionally check valves located at the entrances to the heat transfer distribution collectors from the closed supply communication divided into two parts by closed valves, as well as at the entrances to the coolant circulation circuit from the supply pipelines water from tanks for storing emergency water supplies.