JPH068917B2 - Air extractor driven steam breaker interlock device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] In the present invention, in an auxiliary steam system and an exhaust gas treatment system of a power plant, when an internal power source is lost, the air extractor driving steam is made to flow in or out of the exhaust gas treatment system. Thus, the present invention relates to an interlock device suitable for preventing pressure rise and protecting exhaust gas treatment equipment.

[Background of the Invention]

Second conventional general exhaust gas treatment system and auxiliary steam system
A brief description will be given with reference to the drawings.

Oxygen, hydrogen gas, and leaked air from the atmosphere decomposed in the reactor are collected in a condenser and extracted by an air extractor. Oxygen and hydrogen are recombined in the extracted exhaust gas in the recombiner, air is cooled in the exhaust gas condenser and the driving steam and associated steam in the second stage of the air extractor are condensed, and the rare gas hold-up tower is used. After removing the radioactive material, it is released from the system through the exhaust stack. The main steam from the reactor is used as the drive steam for the air extractor, and the pressure is adjusted to the specified pressure by the air extractor drive steam pressure control valve. On the other hand, the cooling water for the exhaust gas condenser is supplied by the cooling water pump for the auxiliary cooling water system in the power plant.

With the above configuration, when the power supply in the power plant is lost, the cooling water pump that supplies the cooling water for the exhaust gas ascites device is also stopped. On the other hand, the driving steam for the air extractor will continue to be supplied even after the power is lost.

As a result, live steam flows into the downstream side without being condensed in the exhaust gas condenser.

As a result, the inflow condition greatly exceeded the treatment capacity of the exhaust gas condenser downstream device, and as shown in Fig. 7, a large pressure rise (usually the atmospheric pressure rises to about 14 kg / cm ² g) and a Moisture is adsorbed by the rare gas hold-up tower due to the inflow of steam, and it becomes impossible to maintain the performance of the tower, and eventually radioactivity is released outside the system. The cooling water pump and the seawater pump for indirectly cooling the cooling water with seawater are connected and disconnected to the diesel power source,
In some cases, the pump is automatically restarted when the power is lost, but in recent years the cooling water pump tends to remain stopped when the power is lost in order to prevent the capacity of the diesel generator from increasing due to heavy pump load. However, there arises a problem that the above-mentioned exhaust gas condenser cannot condense.

Note that, as a related technique, for example, SAIkai Sho 52-1233
There is number 00.

[Object of the Invention]

An object of the present invention is to solve the problems of pressure rise and radioactivity release at the time of power loss in the exhaust gas treatment system described above, and to provide safe power plant operation.

[Outline of Invention]

It is possible to avoid the above-mentioned problems of the exhaust gas treatment system by cutting off the steam flowing into the exhaust gas treatment system at the upstream of the exhaust gas condenser at the time of power loss. The present invention relates to an electric power source in a power plant in a drive steam system including an air extractor driven by steam generated in a nuclear reactor of a nuclear power plant and a pipe and a valve for supplying the drive steam to the air extractor. A signal representing a loss is provided as a signal source, and an interlock for receiving the signal and forcibly and fully closing the valve of the steam system driven by the air extractor is provided.

Example of Invention

 One embodiment of the present invention is shown in FIG.

The difference from the conventional example is that a line 17 for extracting trip signals from all the cooling water pumps 16 for supplying cooling water to the exhaust gas condenser 12 is provided, and the air extractors 5 and 6 drive steam pressure control valve 8 and pressure control. A device having a function of converting an electric signal and an air signal into a control air line between the pressure regulators 9 and a function of shutting off control air from the pressure regulator 9 and forcibly closing the pressure regulator valve 8 completely. 18 is provided. In a general BWR plant, the steam generated from the reactor 1 works in the turbine 2 and is condensed in the condenser 3 to be condensed water. But the condenser 3
The non-condensed oxygen, hydrogen, and leaked air from the atmosphere are extracted from the first stage 5 of the air extractor. The extracted exhaust gas together with the drive steam of the second stage 6 of the air extractor 10
After being heated at 1, the oxygen and hydrogen are recombined in the recombiner 11 to become water vapor, which is sent to the exhaust gas condenser 12 together with the driving steam and air and condensed by the cooling water. The radioactive substance mixed in the non-condensed air is dehumidified in the exhaust gas dehumidifying tower 13 and then discharged from the upper exhaust pipe 15 after removing the radioactive substance in the rare gas hold-up tower 14. The main steam from the reactor 1 is used as the driving steam for the air extractors 5 and 6, and the pressure regulator 9 is used.
And, the pressure is adjusted to the specified pressure by the pressure control valve 8. on the other hand,
The cooling water of the exhaust gas condenser 12 is supplied by the cooling water pump 16 of the auxiliary cooling water system in the power plant. With the above configuration, when the power supply in the power plant is lost, the interlock signal of all trips of the cooling water pumps 16 is sent to the above-mentioned converter 18, so that the converter does not depend on the normal control air of the pressure regulator 8. The pressure control valve 7 is forcibly fully closed by the control air from 18.

As a result, the steam for driving the air extractors 5 and 6 is cut off by the pressure control valve 7.

According to this method, the inflow of steam to the exhaust gas condenser and the downstream side is stopped and the rise of pressure in the exhaust gas system and release of radioactivity are prevented.

FIG. 3 shows an example in which the signals of all trips of the cooling water pumps are sent to the front valve 19 of the pressure control valve 7 to forcefully close the front valve 19, and in this example, steam is turned off.

FIG. 4 is an example in which the interlock signal of FIG. 1 is sent to the main valve 20 of the steam used as the auxiliary steam from the main steam together with the driving steam of the air extractors 5 and forcibly fully closed.

FIG. 5 shows an example in which one of several kinds of signals 21 associated with the power loss other than the trip signal for all the cooling water pumps is used as the signal for forcibly closing the valve.

Fig. 6 shows an air-operated steam stop valve 2 at the inlet of the exhaust gas condenser 12
3, a steam branch pipe 26, an air-operated steam discharge valve 25 are provided, converters 22 and 24 for converting signals from all cooling water pump trips to air signals are provided, and all trip signal 1
7, the air-operated stop valve 23 is forcibly and fully closed, and at the same time, the air-operated steam discharge valve 25 is forcibly and fully closed, and the steam is discharged into the water in the hot well 25, which is a water reservoir in the condenser 3. According to this example, the condenser 3 and the turbine 2 can be safely isolated from the influence of steam inflow, while the steam can be turned on or off to the exhaust gas condenser 12.

〔The invention's effect〕

According to the present invention, when power is lost, steam can be turned on and off to the exhaust gas condenser 12 and the downstream side, and the following effects can be obtained.

(1) By using the cooling water pump 16 for the exhaust gas condenser 12 as a regular power source instead of a diesel power source, the facility cost of the power source facility can be reduced.

(2) The maximum operating pressure of the exhaust gas treatment system, especially the downstream of the exhaust gas condenser 12, can be lowered, and the facility cost can be reduced.

(3) It is possible to prevent loss of dehumidification and radioactive substance removal performance due to vapor inflow into the exhaust gas dehumidification tower 13 and rare gas holdup tower 14 of the exhaust gas treatment system, and to improve equipment protection and operational reliability.

[Brief description of drawings]

FIG. 1 is a system diagram of an embodiment of the present invention, FIG. 2 is a system configuration diagram of an exhaust gas treatment system and an auxiliary steam system of a conventional power generation plant, FIGS. 3, 4, and 5. FIG. 6 is a system diagram of an embodiment of the present invention, and FIGS. 7 and 8 are diagrams showing changes in pressure rise and adsorbed water content when steam flows into the exhaust gas condenser downstream. 1 ... Reactor, 2 ... Turbine, 3 ... Condenser, 11 ... Recombiner, 12 ... Exhaust gas condenser, 13 ... Exhaust gas dehumidifying tower, 18 ...
Converter, 22, 24 ... Converter, 26 ... Hotwell.

Claims (1)

[Claims] 1. A drive steam system comprising an air extractor driven by steam generated in a nuclear reactor of a nuclear power plant and a pipe and a valve for supplying drive steam to the air extractor in a power plant. Is provided as a signal source, and an interlock for receiving the signal to forcibly fully close the valve of the steam system driving the air extractor is provided. apparatus.