JPS6349758Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an apparatus for treating radioactive gaseous waste discharged from a nuclear power plant.

[Technical background of the invention]

In boiling water nuclear power plants, the gas generated in the reactor core is guided along with steam directly through the turbine to the main condenser, and the gas in the main condenser is exhausted to the outside, but the radioactivity of this exhaust gas is Gaseous waste treatment systems are provided to reduce levels.

FIG. 1 is a schematic diagram of a conventional radioactive gas waste treatment system, and first, this radioactive gas waste treatment means will be explained.

The exhaust gas extracted from the main condenser 1 by the ejector 2 is heated in the preheater 3, and the hydrogen and oxygen in the exhaust gas are reacted in the recombiner 4, and the water is reused within the plant.

The temperature of the remaining exhaust gas discharged from the outlet of the recombiner 4 is about 440°C, and most of it is superheated steam.

This exhaust gas exchanges heat with cooling water in the exhaust gas condenser 5, and at the outlet of the condenser 5, the temperature is approximately 50°C and the relative humidity is
It becomes 100% non-condensable gas.

It is necessary to remove moisture from this exhaust gas before introducing it to the activated carbon hold-up device 7, and a dehumidifier 6 is provided for this purpose.

The exhaust gas dehumidified in this manner attenuates a small amount of radioactive gas leaking from the fuel in the activated carbon hold-up device 7, and the treated exhaust gas is discharged through the stack 9.

Note that the vacuum pump 8 is provided to suck and blow exhaust gas downstream.

Further, a regulating valve 11 is interposed in the pipes 10a and 10b connecting the exhaust gas condenser 5 and the dehumidifier 6.

A pipe 12 branches off from the upstream side of the regulating valve 11, and a trap 13 is connected to the pipe 12.

The downstream side of the trap 13 is connected to the main condenser 1 by a return pipe 14.

Further, a drain pipe 15 is connected from the dehumidifier 6, and the drain pipe 15 is connected to a trap 16.
The downstream side of the trap 16 is connected to the main condenser 1 by a return pipe 17.

[Problems with background technology]

Piping 10a, 1 from the exhaust gas condenser 5 to the dehumidifier 6 in the radioactive gas waste treatment system
0b is very long due to the layout of the system, and there are also level restrictions due to the installation, so when the exhaust gas temperature in the system falls below the outside temperature, the upstream side of the pipes 10a and 10b Condensed water accumulates.

Further, since there is no degree of freedom in the angle of the mounting position of the regulating valve 11, the piping 10a is sloped or has a bent portion, so that condensed water tends to accumulate in the upstream piping 10a.

If condensed water accumulates above the center of the pipe 10a, the flow path resistance will increase due to the flow of exhaust gas, a hunting phenomenon will occur, and an intermittent phenomenon, that is, a breathing phenomenon at the valve portion, will occur, reducing its function. This may cause a decrease in system operating efficiency, stability, and reliability.

[Purpose of invention]

The present invention was made to eliminate the above-mentioned drawbacks, and the outside air temperature is lower than the temperature of the exhaust gas in the radioactive gas waste treatment system, and condensed water is generated and accumulates in the upstream piping 10a of the regulating valve 11. Another object of the present invention is to provide a radioactive gaseous waste treatment device that does not disturb the flow of the system or deteriorate its functionality due to condensed water.

[Summary of the idea]

That is, the present invention provides a gaseous waste treatment system in which gaseous components in steam generated in a nuclear reactor are sequentially passed through a condenser, a regulating valve, and a dehumidifier and then released into the atmosphere. This gaseous waste treatment apparatus is characterized in that a bypass pipe communicating with a downstream piping section is provided below the center of the piping connected to the regulating valve.

[Example of idea]

Hereinafter, an embodiment of the gaseous waste treatment apparatus according to the present invention will be described with reference to FIGS. 2 and 3.

In FIG. 2, parts that are the same as those in FIG. 1 are indicated by the same reference numerals, and explanations of parts that overlap with those in FIG. 1 will be omitted.

FIG. 3 is a perspective view of FIG. 2.

That is, in FIGS. 2 and 3, the regulating valve 11 is connected between the upstream pipe 10a and the downstream pipe 10b.

The regulating valve 11 has a valve seat 23 having a flow passage hole 22 attached to a partition part 21 in a valve box 20.
A valve portion 24 inserted into the valve 3 is connected to a valve rod 25.

Then, the upstream pipe 10a and the downstream pipe 10b
are provided with connection joints 26 and 27, respectively, and these joints 26 and 27 are connected to a bypass pipe 28.
is connected to the bypass pipe 28, and a cutoff valve 29 is inserted approximately in the center of the bypass pipe 28.

The connection position of the bypass pipe 28 to the pipes 10a and 10b needs to be maintained at a level where the condensed water 30 easily flows from the upstream side to the downstream side, that is, at a portion facing downward from the center of the pipe diameter.

In addition, the shield valve 29 must be able to allow liquid to flow from one side to the other when the circuit is open, and to stop the flow of liquid when the circuit is closed, and a Kotsuk type valve may also be used. It may be incorporated into an automatic sequence to automatically open and close electrically.

Therefore, in the regulating valve device having the above configuration, the radioactive gaseous waste that is discharged from the main condenser 1 after doing work in the steam turbine is transferred to the ejector 2, the preheater 3,
It flows sequentially through the recombiner 4, exhaust gas condenser 5, dehumidifier 6, activated carbon holdup 7 and vacuum pump 8 to be treated and discharged from the stack 9 through the process system.

Here, during normal operation of the process system, the bypass pipes 28 provided on both sides of the regulating valve 11 are closed to the cutoff valve 29, so when the exhaust gas falls below the outside temperature, the upstream piping 10a of the regulating valve 11
The condensed water accumulates in the condensed water 30.

Therefore, the bypass pipe 28 is opened by opening the cross section 29.
The upstream piping 10a and the downstream piping 10b are made to communicate with each other, and the condensed water 30 accumulated in the upstream piping 10a is made to flow through the bypass pipe 28 to be connected to the downstream piping 10b.
Pour into.

The opening valve 29 can be operated by manually opening it when the condensed water 30 accumulates in the upstream pipe 10a, or by incorporating it into an automatic sequence when the outside air temperature drops below the exhaust gas temperature. .

Thus, the condensed water 30 flows to the dehumidifier 6 on the downstream side without accumulating in the pipe 10a, and is discharged using the drain mechanism of the dehumidifier 6.

[Effect of idea]

As described above, according to the present invention, the adjustment valve installed in the process system of a radioactive gaseous waste treatment plant cannot be mounted in a flexible manner due to the layout, and its upstream side is connected to the upright pipe 10a. When pipes are connected together, condensed water will not accumulate above the center of the pipes.

Therefore, the flow path resistance does not increase due to the flow of exhaust gas, the hunting phenomenon can be prevented, and furthermore, there is an effect that the breathing phenomenon at the valve part due to the intermittent phenomenon can be prevented.

Further, since the condensate that accumulates on the upstream side of the regulating valve can be easily extracted, there is no need to provide a special condensate discharge mechanism in the regulating valve.

Therefore, it provides advantages such as improved operating efficiency and improved stability of the radioactive gaseous waste treatment system.

[Brief explanation of drawings]

Fig. 1 is a schematic system diagram showing a conventional radioactive gas waste treatment process system, Fig. 2 is a vertical cross-sectional view partially showing a side view of the radioactive gas waste treatment regulating valve according to the present invention, and Fig. 3 is a schematic system diagram showing a conventional radioactive gas waste treatment process system. FIG. 2 is a perspective view of FIG. 2; 1... Main condenser, 2... Ejector, 3... Preheater, 4... Recombiner, 5... Condenser, 6... Dehumidifier, 6... Dehumidifier, 7... Activated carbon Hold up, 8... Vacuum pump, 9... Stack, 10
a, 10b...Piping, 11...Adjusting valve, 12...
Piping, 13... Trap, 14... Return piping,
15...Drain piping, 16...Trap, 17...
... Return piping, 20 ... Valve box, 21 ... Partition section, 22 ... Channel hole, 23 ... Valve seat, 24 ... Valve section, 25 ... Valve stem, 26, 27 ... Connection joint, 2
8...Bypass pipe, 29...Shiya valve, 30...
Condensed water.

Claims (1)

[Scope of utility model registration request] In a gaseous waste treatment device in which gaseous components in steam generated in a nuclear reactor are sequentially passed through a condenser, a regulating valve, and a dehumidifier and then released into the atmosphere, an upstream piping section and a downstream piping section of the regulating valve are provided. A gaseous waste treatment apparatus, characterized in that a bypass pipe communicating with the regulating valve is provided below the center of the pipe connected to the regulating valve, and the bypass pipe is further provided with a cutoff valve.