JPS59217199A - Gaseous waste processing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radioactive gaseous waste treatment device for a boiling water nuclear power plant.

[Technical background of the invention and its problems] In general, a gaseous waste (hereinafter referred to as exhaust gas) treatment device in a boiling water nuclear power plant has a main condenser 1, a 1st stage air extractor 2, intercondenser 3, start/stop air extractor 4, 2nd stage air extractor 5, preheater 6, recombiner 7, condenser 8, precooler 9, sand filter 10, A dryer 11, an activated carbon hold up tower 12, a particle filter 13, a vacuum pump 14 and a stack 15 are connected in series by piping.

Further, a condenser vacuum pump line 18 branched from the second stream of the condenser 8 and connected to the main condenser vacuum pump 17 and a return line 16 to the main condenser 1 are provided for starting or stopping the condenser 8. Furthermore, pressure gauges 19, 22 and 23 are provided on the outlet sides of the condenser 8, precooler 9, and particle filter [3], respectively. Further, a pressure control valve 21 is provided on the inlet side of the main condenser of the reflux line [6], and a flow meter 20 is provided on the inlet side of the precooler 9.

The startup procedure for the exhaust gas treatment device configured as described above is as follows: First, the main condenser vacuum pump 17 directly applies vacuum l to the main condenser.
Subtract W to a certain value, then start/stop air extractor 4,
The preheater 6, the recombiner 8, and the condenser vacuum pump line 18 of the condenser vacuum pump 17 are used to exhaust air, and the first stage air extractor 2, the intercondenser 3, the second stage air extractor 5, Preheater 6, recombiner 7, condenser 8, reflux line 16
Finally, the IT stage raw air extractor 2 intercondenser 3, second stage air extractor 5, preheater 6, recombiner 7, condenser 8, precooler 8, sand filter 10 , dryer 11. The procedure for stopping the activated carbon hold-up tower 12 and the exhaust gas treatment device is an operation procedure that is the opposite of the above-mentioned startup procedure. By the way, if the reactor steam, which is the driving source for the first stage air extractor 2 and the second stage air extractor 5, falls below a specified value, the start/stop air extractor 4 is activated and the main condenser Maintain a vacuum of l.

In such an exhaust gas treatment system, if the reactor were to scram, the outlet pressure of the condenser 8 and the population flow rate of the precooler 9 would increase. Therefore, the pressure control valve 2L of the recirculation line [6 is opened to maintain the outlet pressure of the tree felling machine 8 constant, and the exhaust gas is returned to the main condenser L. At this time, the inlet flow rate of the precooler &8 also decreases, and furthermore, the exhaust gas downstream of the precooler 8 is also drawn to the main condenser 1. As a result, as shown in FIG. 2, the inlet pressure of the sand filter 0 on the downstream side of the precooler 9 and the outlet pressure of the particle filter 3 are reversed compared to the pressures during normal operation. In other words,
Since the outlet output of the particle filter 13 becomes higher than the inlet pressure of the sand filter IO, as shown in FIG. There is a risk that the sand filter 10 will flow upstream from the filter 10 to the upstream direction 11. This is because the sand filter 10 is normally designed for flow in the normal direction as shown by the solid arrow, and no measures are taken against the flow in the reverse direction. This is because it has not been done. If the sand 24 in the sand filter 10 flows out into the upstream piping, the piping will eventually become clogged, potentially interfering with the operation of the exhaust gas treatment system.

In this way, when sand flows upstream and accumulates in upstream piping, it is necessary to cut the piping and remove the sand, and as this work is carried out within a radiation-controlled area, depending on the situation, It is predicted that a situation will arise in which the plant will have to be shut down.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to provide an exhaust gas treatment device that can operate safely even when an abnormality occurs in a nuclear reactor.

[Summary of the invention]

In order to achieve the above object, the present invention detects the flow rate at the inlet of the exhaust gas precooler of the exhaust gas treatment device when the reactor is scrammed, and as soon as this flow rate decreases to zero, the flow rate of the exhaust gas precooler is immediately activated. This relates to an exhaust gas treatment device that automatically closes a control valve installed at the inlet to prevent the sand filter inlet pressure and particle filter outlet pressure from reversing.

[Embodiments of the invention] An embodiment of the present invention will be described with reference to the drawings.

FIG. 4 shows a piping system diagram of an exhaust gas treatment apparatus according to an embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals for explanation.

As shown in FIG. 4, the exhaust gas treatment device according to the present invention includes a main condenser 1% first stage air extractor 2, an ink condenser 3, a start/stop air extractor 4, and a second stage air extractor. Vessel 5,
Preheater 6, ladle combiner 7, condenser 8, precooler 9, sand filter 10, dryer 11, activated carbon hold up tower 12
, a particle filter 13, a vacuum pump 14, and a stack 15 are connected by piping, and a vacuum pump 17 for the main condenser is branched from the downstream of the condenser 8 for starting or stopping.
Main condenser vacuum pump line 18 connected to main condenser l
A reflux line 16 is provided to.

In addition, pressure gauges 19, 22 and 23 are provided at the outlets (111) of the ascites device 8, precooler 9 and particle filter 13, respectively. A pressure control valve 21 is provided on the inlet side, and a flow meter 20 is provided on the intake side of the precooler 9.The configuration described above is no different from the configuration of a conventional exhaust gas treatment device. In the present invention, the above-mentioned exhaust gas treatment device is provided with a flow meter 20 for measuring the exhaust gas inlet flow rate n1 to the precooler 9 and a large mouth valve 25, and the precooler 9 is adjusted according to the magnitude of the exhaust gas flow rate measured by the flow HL meter 20. A large mouth valve 25 provided on the inlet side is controlled (III).

For example, when explaining a 100,000 KW class nuclear power plant, the exhaust gas inlet flow rate of the precooler 9 is a maximum of 8 ONm.
”/h, usually 4ONrn'/h.
When the reactor scrams, the exhaust gas flow rate increases and the pressure on the outlet side of the water tank 8 reaches the set value of 0.85 at 9/at? It rises from ab. At the same time, when the pressure is restored to its original level, the pressure control valve 21 disposed in the return line 16 to the main condenser 1 opens, acting to lower the pressure on the outlet side of the condenser 8. At this time, the exhaust gas inlet flow rate to the exhaust gas precooler 9 gradually decreases and eventually rises to ON, σh. At this time, the gas flow rate is detected by the detector 26, and this detection (
R is sent to the electro-pneumatic converter 27, and the inlet valve 26 of the precooler 9 is
Let be closed.

By controlling the exhaust gas flow rate in this way, the pressure on the outlet side of the particle filter 13 installed in the exhaust gas treatment device does not become higher than the pressure at the inlet f11 of the sand filter 10. This means that when the outlet pressure of the condenser 8 is equal to the set value, the inlet valve 26 of the precooler 9
It's a shame that you don't open it.

[Effects of the Invention] According to the present invention, there is no backflow of exhaust gas in the exhaust gas treatment equipment in the event of a nuclear reactor scram accident.
For example, the sand in the sand filter will not scatter. Therefore, unlike conventional work, there is no work due to the scattering of sand in the sand filter, reducing the exposure of workers to radiation, and since valve production is automatically operated, there is less negative JLU for the plant operation team. It is possible to provide an exhaust gas treatment device that does not increase the amount of waste gas.

[Brief explanation of drawings]

Figure 1 is a piping system diagram of a conventional exhaust gas treatment equipment, Figure 2 is a pressure state diagram of the sand filter and particle filter used in the conventional exhaust gas treatment equipment when a nuclear reactor is scrammed, and Figure 3 is a diagram of the conventional exhaust gas treatment equipment. FIG. 4 is a schematic sectional view of a sand filter, and FIG. 4 is a piping system diagram of an exhaust gas treatment device according to an embodiment of the present invention. 1... Main condensate g# 2 + 4 + 5...
・Air extractor 3...Intercondenser 6...
Preheater 7... Recombiner 8... Condenser 9...
・Precooler 10・-Sand filter 11...
Dryer [2... Activated carbon bold-up column 13... Particle filter 14... Vacuum pump 15... Stack 16... Reflux line [7... Main circulation I7
! 5 Vacuum pump 18... Vacuum pump line for main water boiler 19122.2
3...Pressure gauge 20...Flow meter 2L, 25...
Pressure control valve 24...Sand 26...Meter for flow 11 27...Electro-pneumatic converter representative Patent attorney Noriyuki Chika (one person) Figure 1 Figure 2 Figure 2 From Samurai Nmu Main - Figure 3 Figure 4

Claims (2)

[Claims] (1) Air extractor, recombiner, exhaust gas condenser, exhaust gas precooler, to treat gaseous waste from the main condenser;
sand filter, activated carbon hold up tower, filter,
・In a gaseous waste treatment device in which a vacuum pump and a stack are connected via piping and a return line to the main condenser is provided upstream of the exhaust gas precooler, a flow meter and a control valve are installed at the inlet of the exhaust gas precooler. A gaseous waste treatment apparatus characterized in that the control valve is controlled by a detection signal from the flowmeter. (2) Claim 1, wherein the control valve provided at the inlet of the exhaust gas precooler is immediately closed when a flow meter detects that the flow rate at the inlet of the exhaust gas precooler has decreased to zero. Gaseous waste treatment equipment as described.