JPS61129547A - Adjusting method of sampling flow rate - Google Patents

Abstract

PURPOSE:To eliminate the manhour required for detaching a flange part, and to improve the operation efficiency of a flow rate adjustment, and to reduce the cost by providing a nozzle for fitting a pressure gauge to a sampling pipe nearby a valve for flow rate adjustment. CONSTITUTION:The nozzle 15 for fitting a pressure gauge to the sampling pipe 4 is provided nearby the valve 5 for flow rate adjustment and the nozzle 15 is normally blocked by providing a nozzle lid 16. When a flow rate adjustment is made, the pressure gauge 17 is fitted to the nozzle 15. Then, the flow meter in a detection part measures the total flow rate and flow rates adjusting valves 5 are so adjusted that respective pressure gauges 17 generate the same indication, thereby equalizing flow rates in respective sampling pipes 4 to each other. Consequently, the flange part need not be provided to each sampling pipe and a sampling system is assembled efficiently. Further, the maintenance time of a leak detection system is shortened and the safety of the plant is improved as a result.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a sampling flow rate adjustment method used in a sodium leak detection system that detects sodium leakage from sodium cooling system piping using a gas sampling method.

[Technical Background of the Invention] In a fast breeder reactor that uses liquid sodium as a coolant, if a crack occurs at the boundary of equipment or piping containing sodium, sodium leaks through the crack. In that case, it is very important to detect sodium leakage at an early stage.

In other words, when sodium leaks, the leaked sodium comes into contact with the external atmosphere where equipment or piping is installed, reacts with oxygen and water vapor in the atmosphere, and forms sodium hydroxide (NaOH) and sodium oxide (Na20). Produces corrosive compounds such as

Therefore, if the discovery is delayed, the cracks may expand due to corrosion, potentially causing a large-scale sodium leak. If a large amount of sodium leaks, a large amount of reaction heat will be generated, which poses a problem in terms of plant safety.

Furthermore, from the viewpoint of time and cost required for maintenance, it is desirable to detect small leaks at an early stage.

Conventionally, contact-type sodium leakage detection methods have been known, in which electrodes are installed in advance at the bottom of equipment containing sodium, and leakage of sodium can be detected by short-circuiting the electrodes with accumulated leaked sodium. It is being

This detection method is suitable for medium-sized and large-scale leaks.
It is not suitable for detecting minute leaks with a leakage rate of ~100 (1/h).

On the other hand, a gas sampling method is known as a method for detecting minute leaks.

The gas sampling method utilizes the fact that leaked sodium reacts with water vapor and oxygen contained in gases in the atmosphere to generate sodium aerosols such as sodium hydroxide and sodium oxide.

In this method, a space is created around the equipment to be detected for leakage, and the atmospheric gas in that space is sampled and guided to a detector, etc. When sodium leaks, sodium aerosol is sampled along with the atmospheric gas. Detect sodium leaks by detecting sodium in the gas.

That is, the conventional gas sampling method will be explained with reference to FIG.

In Fig. 4, reference numeral 1 is a sodium pipe through which sodium flows. If sodium leaks from this flow pipe 1, the leaked sodium reacts with the atmospheric gas in which the pipe 1 is installed, generating sodium aerosol. . The generated aerosol is transferred to a pipe storage room 6 by a sampling pipe 4 that samples the atmospheric gas in the space formed between the pipe 1 and the heat insulating material 2, that is, the annulus space 3.
is sampled outside of. The sampling pipe 4 is combined with other sampling pipes and connected to a valve 5.
One for each set is connected to the header 7 via. header 7
The sampled gas passes through the confluence pipe 10 and is detected by the detector 8. The gas that has flown out of the detector 8 is returned from the pump 9 to the pipe storage room 6 through the return pipe 11.

On the other hand, when such a sampling method is used, the sodium pipe 1 is connected to the annulus space 3 by the clamp 12 provided between the pipe 1 supporting the pipe 1 and the heat insulating material 2.
Since the space is partitioned, a sampling pipe 4 is attached to each partition.

[Background Art Problem 1] However, when such a sampling method is used, the length of the sampling pipe 4 to the header 7 differs for each sampling pipe 4.

For this reason, even if sampling is performed using a flow rate equal to the number of trees in the sampling pipes 4 from the header 7 in which a plurality of sampling pipes 4 are grouped together, the flow rate in each sampling pipe 4 will differ.

In order to detect sodium leaks with the same performance, each sampling pipe must be sampled with the same sampling flow rate.

A conventional method for adjusting the sampling flow rate will be explained with reference to FIGS. 5 and 6.

These figures are enlarged views of the sampling pipe 4 in FIG. 4 to the pump, and as shown in FIG. When adjusting the flow rate, remove the piping from the piping flange section 13, attach the flowmeter 14 as shown in Fig. 6, and adjust the flow rate.
Adjustment valve 5 is used to adjust the flow rate in each sampling pipe to be equal.

When using such a flow ffi adjustment method, since a large number of sampling pipes are installed in an actual plant, it is necessary to remove the flange 13 of the pipe 7 and attach the flow meter 14 when adjusting the flow rate. This is extremely time-consuming work.

OBJECT OF THE INVENTION] The present invention has been made to eliminate the above-mentioned drawbacks, and improves work efficiency by eliminating the trouble of removing the flange portion and making it possible to adjust the flow rate by performing simple processing on the sampling pipe. The object of the present invention is to provide a flow m adjustment method that contributes to cost reduction.

[Summary of the Invention] That is, the sampling flow rate adjustment method of the present invention collects a plurality of sampling pipes and other sampling pipes, and connects each set to a header via a flow rate adjustment valve. A gas sampling system consisting of a pump that guides the collected gas to a detection unit through a confluence pipe, and a pressure gauge mounting nozzle provided in the sampling pipe near the flow rate adjustment valve to change the differential pressure with the position of the pump. The feature is that the sampling 1ffi is adjusted by.

According to the present invention, since the sampling flow port is adjusted by changing the differential pressure with respect to the pump position, flow rate adjustment is easy, work efficiency is improved, and costs are reduced.

[Embodiment 1 of the Invention An embodiment of the method according to the present invention will be described below with reference to FIGS. 1 and 2.
This will be explained with reference to the figures.

In FIG. 1, reference numeral 15 is a nozzle for attaching a pressure gauge to the sampling pipe 4 shown in FIG. 4, and this nozzle 15 is installed near the flow rate adjustment valve 5 as shown in FIG. There is. A nozzle lid 16 is provided on the nozzle 15, and the nozzle 15 is normally closed.

When adjusting the flow rate, a pressure gauge 17 is attached to the nozzle 15 as shown in FIG. The total flow rate is measured with a flow meter in the detection section, and the flow rate adjustment valve 5 is adjusted so that the readings of each pressure gauge 17 are the same, so that the flow rate in each sampling pipe 4 is made equal.

FIG. 3 shows another embodiment of the present invention, and this embodiment differs from the previous embodiment in that a second pressure gauge 18 is installed in the header 7 or in a detection section not clearly shown in the figure. When the total flow rate is constant, the pressure at the position of this second pressure gauge 18 is a constant value. When adjusting the flow rate, use sampling pipe 4.
the pressure at the position of each first pressure gauge 17 attached to;
The valve 5 is adjusted so that the differential pressure with the pressure at the position of the second pressure gauge 18 is equalized, and the flow rates in each sampling pipe are equalized. After adjusting the flow rate, the first pressure gauge 17 is removed and the nozzle 15 is closed with a nozzle lid 16.

[Effects of the Invention] According to the present invention, when adjusting the sampling Ptff1 with the same level of adjustment performance as the conventional one, the effort of removing the 7-lunge portion can be saved and work efficiency can be improved. Additionally, there is no need to provide a flange on the sampling piping.
Work efficiency can be improved when assembling the sampling system. When performing maintenance on the leak detection system, the maintenance can be completed in a short time, contributing to improved plant safety.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams for explaining the sampling flow rate adjustment method according to the present invention. Figure 1 is a front view showing the main parts in cross section, Figure 2 is a piping system diagram, and Figure 3 is the main part. Piping system diagrams for explaining other embodiments of the invention, FIGS. 4 to 6
The figures are diagrams for explaining a conventional example, and Fig. 4 is a system diagram schematically showing a sodium leak detection device, and Figs. 5 and 6 are diagrams for explaining a conventional example.
Each figure is a piping system diagram of FIG. 4. 1...Sodium piping 2...
・・・・・・・・・Heat insulation material 3・・・・・・・・・Annual space 4・・・・・・
・・・・・・・・・Sampling piping 5・・・・・・・・・
... Valve 6 ...... Piping storage room 7 ...
......Header 8...Detector 9...Pump 10... Merging pipe 11...
・・・・・・Return piping 12・・・・・・・・・・・・
Clamp 13...Piping flange 14...Flowmeter 15...Nozzle 16... ...Nozzle lid 17.18...
・Patent attorney for pressure gauge Satoshi Suyama - Figure 1, Figure 2, Figure 4, ``li''

Claims (2)

[Claims] (1) A pump that guides the sampled gas to the detection unit through the merging pipe is connected to a header that brings together the sampling pipe and other sampling pipes in one place for each set via a flow rate adjustment valve, and A nozzle for attaching a pressure gauge is installed in the sampling pipe near the adjustment valve, the total flow rate is measured with the flowmeter in the detection section, and the valve opening is adjusted so that the indications of each pressure gauge attached to the nozzle position are the same. A sampling flow rate adjustment method characterized by adjusting the flow rate in each sampling pipe by adjusting the flow rate in each sampling pipe. (2) The sampling flow rate adjusting method according to claim 1, characterized in that the flow rate in each sampling pipe is adjusted by attaching a pressure gauge to the header and adjusting the differential pressure with the nozzle position. .