RU2105360C1 - Overpressure device for protecting nuclear reactor interior in case of emergency emission of steam-gas medium - Google Patents

Abstract

FIELD: nuclear power engineering. SUBSTANCE: device has condenser and gas-holder communicating through header. Gas holder is connected via piping to helium cleaning plant communicating with ventilation pipe. Installed upstream of condenser is safety facility controlled by pressure sensor installed in reactor interior. Device is provided, in addition, with decay chamber connected to radiation activity suppression plant which communicates with ventilation pipe. Second safety facility also controlled by pressure sensors is mounted at inlet of decay chamber which functions to operate in response to pressure within reactor interior exceeding operating pressure of first safety facility but not exceeding that permissible for reactor interior. EFFECT: reduced probability of emission of radioactive gases into atmosphere, improved efficiency of cleaning radioactive gases, improved environmental friendliness of nuclear power plants. 1 dwg

Description

 The invention relates to the field of nuclear energy and can be used in the design and operation of energy channel nuclear reactors.

 A modern means of protecting the reactor space (RP) of a channel nuclear reactor from overpressure during accidents caused by a rupture of a fuel or special channel is the device described in the book [1].

 The closest analogue of the claimed technical solution is the device for protecting the RP of a nuclear reactor from overpressure, described on pages 85 and 94 of the above source [1]. The device for protecting the RP of a nuclear reactor from overpressure provides for the removal of the vapor-gas mixture (ASG) from the RP to the gas tank (the circuit diagram of the device is indicated by single lines in the drawing). The device consists of a condenser, a water trap and a gas tank connected by a collector. The capacitor is connected via a pipeline containing a safety device to the RP where a pressure sensor is installed. The gas tank is connected via pipelines to a helium purification unit (UOG).

 The device operates as follows. In the event of an emergency caused, for example, by a rupture of one fuel channel, the pressure of the ASG increases in the RP of the nuclear reactor, which is detected by a pressure sensor installed in the PC.

 When the pressure P1 reaches RP, the nuclear reactor stops and a safety device opens. ASG from RP through pipelines enters the condenser, where steam condensation occurs. Non-condensable gases enter the gas tank through the collector.

 In the event of a beyond design basis accident related to the rupture of two or more fuel channels, the gas pressure in the manifold increases to P2. In this case, a water lock is triggered and part of the crude radioactive gases is emitted through the ventilation pipe into the atmosphere.

 The disadvantage of the device for protecting RP from overpressure by the closest analogue is the insufficient level of radiation and environmental safety, which does not exclude the release of radioactive gases into the atmosphere.

 The problem solved by this invention is the creation of a device to protect the RP of a nuclear reactor from overpressure during emergency release of ASG, excluding the release of radioactive gases into the atmosphere.

 The essence of the claimed invention lies in the fact that the device for protecting the RP of a nuclear reactor from overpressure during emergency release of ASG, containing a condenser, gas holder and a water seal, connected by a collector, a ventilation pipe, a safety device, is additionally equipped with a holding chamber connected to a radiation suppression unit ( UPAK), which communicates with the ventilation pipe, the second safety device associated with the pressure sensor installed at the entrance to the holding chamber. The use of a holding chamber and UPAK in the RP protection device will allow receiving significantly larger volumes of radioactive gases emitted from the RP without increasing the pressure in the collector, which prevents their release into the atmosphere through the hydraulic seal in the event of rupture of two or more fuel channels. In addition, it will increase the efficiency of radioactive gas purification, which will increase the environmental safety of nuclear power plants.

 The essence of the claimed technical solution is illustrated by a schematic flow diagram of a device for protecting the RP of a nuclear reactor from overpressure during an emergency release of ASG shown in the drawing. Single lines show equipment and pipelines in common with the closest analogue. Double - equipment and pipelines, additionally introduced into the device.

 The device consists of a pressure sensor 1 installed directly in the RP 2, pipelines 3, the first safety means 4, a capacitor 5 connected by means of a manifold 6 with a water lock 7, a gas holder 8, and a holding chamber 9. Between the gas tank 8 and the holding chamber 9, a second safety device 10 is provided on the manifold 6, the actuation pressure of which is determined by the maximum permissible pressure value (P3) in the RP 2. The gas tank 8 is connected by pipelines to the UOG 11, the holding chamber 9 is connected to the UPAK 12. Hydraulic lock 7, UOG 11 and UPAK 12 are connected by individual pipelines to the ventilation pipe 13.

 When a nuclear reactor is operating in the holding chamber, gas is purified from the gas circuit of the nuclear reactor.

 The device operates as follows.

 In the event of an emergency caused, for example, by a rupture of one or more fuel channels, the ASG pressure in RP 2 rises, which is recorded by the pressure sensor 1.

 The signal from the pressure sensor 1 on the increase in pressure in RP2 to the value P1 triggers emergency protection of the nuclear reactor and the first safety device 4, the reactor stops, the safety device opens. The gas-vapor mixture through pipelines 3 enters the condenser 5, where the condensation of steam occurs. Non-condensable radioactive gases enter the collector, the gas tank 8 and create pressure in the hydraulic lock 7. In the gas tank 8, the gases are held and gradually fed to the UOG 11, where they are cleaned of radioactive elements. Further, the purified gases through the ventilation pipe 13 enter the atmosphere. If the pressure of the gas-vapor mixture in the RP continues to increase and reaches the value P3, the second safety device 10 opens upon the signal from the pressure sensor 1 and the gases enter the holding chamber 9, the volume of which is much larger than the volume of the gas holder 8. In the holding chamber 9, the gases are kept and fed to the UPAK 12 for cleaning. The purified gases through the ventilation pipe 13 enter the atmosphere. Hydraulic lock 7 is in reserve and comes into effect only if the ASG pressure in the RP is increased above the maximum permissible value P3.

 The use of this technical solution reduces the likelihood of release of radioactive gases into the atmosphere, increases the efficiency of purification of radioactive gases, increases the environmental safety of nuclear power plants.

Claims (1)

 A device for protecting the reactor space of a nuclear reactor from overpressure during an accidental release of a gas-vapor medium, containing a condenser and a gas holder connected by a collector, while the gas holder is connected by a pipe to a helium purification unit connected by a pipe to a ventilation pipe, the first safety device installed in front of the condenser and controlled by a sensor pressure installed in the reactor space, characterized in that the device is additionally equipped with a camera a ki connected to a radiation suppression installation communicating in the ventilation pipe and a second safety device controlled by a pressure sensor, the second safety device installed at the inlet of the holding chamber and triggered when the pressure in the reactor space is higher than the response pressure of the first safety device, but lower than the maximum permissible pressure in the reactor space.