JPS6156774B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogen detection device that can continuously measure the concentration of hydrogen contained in a gas.

A small water or steam leak in a steam generator in a sodium metal-cooled fast reactor plant can damage adjacent heat exchanger tubes and cause a large-scale leakage accident. Therefore, it is necessary to promptly detect small water or steam leaks to prevent accidents. To detect this water leak, a hydrogen detection device is required that has high sensitivity and can be used for a long period of time. Various means have been considered for detecting water leaks, and among them, means for detecting hydrogen released into the cover gas during the reaction between sodium and water has been used. To detect this hydrogen, a hydrogen detection device equipped with a diffusion membrane section, a vacuum gauge, and an exhaust device is used.

This hydrogen detection device is constructed as shown in FIG. That is, an inlet pipe 2 and an outlet pipe 3 as a gas sampling nozzle are attached to a wall 1 of a cover gas section of a steam generator or a test tank.
Attach the bottom end of the The inlet pipe 2 is connected to the outlet pipe 3 via a first heating source 4 with a built-in heater, a hydrogen detector housing lift 5, a vapor trap 6, and a circulation pump 7 in this order to form a gas circulation loop 8. A vapor trap 6 is provided to prevent sodium vapor from flowing into the circulation pump 7.

The gas to be measured flows in from the inlet pipe 2, is heated by the first heating source 4, is sent to the storage container 5 housing the hydrogen detector, where the hydrogen content is detected, and then vapor trap 6 The gas is then returned to the cover gas section by the circulation pump 7.

On the other hand, a stainless steel tubular body 10 is inserted into the hydrogen detector housing 5 and is attached by a flange 11. A sleeve-shaped diffusion membrane portion 12 is fitted into the tubular body 10, and this diffusion membrane portion 12 is made of palladium, iron, nickel, or the like that allows hydrogen to pass therethrough. A second heating source 13 incorporating an auxiliary heater is provided at the connection portion between the diffusion membrane portion 12 and the tubular body 10.
is provided to prevent heat release from the tubular body 10 due to thermal conduction. Thus, the first heating 4 and the second heating source 13 are adjusted to a predetermined temperature by temperature detection elements 14, 15 such as thermocouples and temperature control devices 16, 17.

Further, a sensor 20 of a hydrogen detector 19 is connected to the flange 11 via a measuring pipe 18, and this sensor 20 is connected to a hydrogen detection controller 2.
1.

Therefore, only hydrogen gas among the gases to be measured supplied to the hydrogen detector storage container 5 passes through the diffusion membrane section 12 and is detected by the sensor 20 of the hydrogen detector 19. If hydrogen is detected, the steam generator is shut down and the heat exchanger tubes are inspected and repaired to prevent accidents.

However, in the conventional hydrogen detection apparatus, since the gas to be measured is forced to circulate by the circulation pump 7, a vapor trap 6 is required to protect it, and a complicated gas circulation loop 8 is required. For this reason, it has been impossible to directly attach the sensor 20 for detecting the amount of hydrogen to the wall 1 of the cover gas section and directly measure the hydrogen concentration in the gas to be measured passing through the cover gas section. In addition, since the hydrogen detection device is provided with a gas circulation loop 8, the entire device becomes larger, and the vapor trap 6 affects the hydrogen concentration of the gas to be measured passing through the cover gas section when the gas to be measured is circulated. , it has become difficult to accurately measure hydrogen concentration.

In consideration of the above-mentioned points, the present invention enables a sensor for detecting hydrogen concentration to be directly attached to the wall of the cover gas section, thereby making it possible to accurately detect hydrogen concentration with a small device without being affected by vapor traps, etc. The purpose of the present invention is to provide a hydrogen detection device that has the following characteristics.

Hereinafter, an embodiment of the hydrogen detection device according to the present invention will be described with reference to FIG.

In FIG. 2, reference numeral 30 indicates a wall of a cover gas section of a test chamber such as a steam generator or a test tank. An extending hollow cylindrical container 32 is fixed. This cylindrical container 32 is formed as a heat shield and is exposed to the cover gas, while its tip is open as a gas inlet 32a to be measured. The upper side of the cylindrical container 32 is formed as a gas outlet 32b to be measured, and is provided with a large number of holes. In this way, an upward flow path 33 of the gas to be measured is formed within the cylindrical container 32.

On the other hand, the cylindrical container 32 accommodates a stainless steel tubular body 34 attached to the flange 31. This tubular body 34 extends downward through the gas outlet port 32b to be measured, and has palladium at the bottom thereof.
Sleeve-shaped diffusion film 3 made of iron, nickel, etc.
5 is fitted. This diffusion membrane portion 35 is connected to the cylindrical container 3.
A first heating source 36 with a built-in heater is installed below the first heating source 36, and a similar second heating source 37 is installed at the connection between the tubular body 34 and the diffusion membrane 35. . The heating amounts of both heating sources 36 and 37 are adjusted and controlled by temperature control devices 38 and 39, and the operation of each temperature control device 38 and 39 is controlled by temperature signals detected by temperature detection elements 40 and 41.

Further, a measuring pipe 43 integrated with the tubular body 34 is attached to the flange 31 from above, and a sensor 45 of a hydrogen detector 44 is attached to the top of this pipe 43, and the hydrogen concentration is measured by the hydrogen detector 44. Ru. The hydrogen detector 44 has a detection unit controller 46 . This detection unit controller 46
functions as a hydrogen detection controller that controls sensor operation, an ion pump controller that measures ion current and vacuum degree, and a vacuum gauge controller.

Next, the hydrogen concentration detection function of this hydrogen detection device will be explained.

The gas to be measured flowing in from the gas inlet 32a is heated by the first heating source 36 and the second heating source 37, thermally expands, becomes lighter, and flows into the upward flow path 3.
3 and flows out from the gas outlet 32b. In this way, the gas to be measured is supplied to the first heating source 36 and the second heating source 37 as an auxiliary heating source.
The measured gas flows in the upward flow path due to natural convection caused by the heating, and the first and second heating sources 36 and 37 act as pumps to circulate the measured gas. Therefore, the circulation pump and vapor trap incorporated in conventional hydrogen detection devices become unnecessary.

Thus, hydrogen contained in the gas to be measured passes through the diffusion membrane section 35 and enters the tubular body 34, is detected by the sensor 45 of the hydrogen detector 44, and the hydrogen concentration is measured.

In this case, the sensor 45 of the hydrogen detector 44 can be directly attached to the wall 30 of the cover gas section of the test room, etc., so there is no need for a conventional forced circulation loop for the gas to be measured, and there is no need for a vapor trap. , hydrogen concentration can be measured with high accuracy without being affected by vapor traps, etc.

Using the gas circulation loop 8 shown in Figure 1, when the flow rate of the gas to be measured is 20/min., the control temperature is 500°C, and the vapor trap outlet temperature is 50°C, the hydrogen concentration is
After measuring the gas to be measured at 1000 PPM, when measuring the gas to be measured at 100 PPM, a value of 110 to 120 PPM was obtained, resulting in a considerable measurement error. However, with the hydrogen measuring device according to the present invention, even in the latter case, the former
It was completely unaffected by the 1000PPM gas to be measured and was able to measure accurately.

As described above, in the hydrogen detection device according to the present invention, a hollow cylindrical container with an upward flow path for the gas to be measured is provided on the wall of the cover gas section, and a heating source is installed in the flow path. However, since the gas to be measured is heated, the gas to be measured flows in the upward flow path by natural convection, and there is no need for a conventional circulation pump or vapor trap. Therefore, the number of components is small, and the hydrogen detection device can be downsized.

In addition, the hydrogen detector only needs to be connected to the tubular body inserted into the cylindrical container, and can be attached directly to the wall of the cover gas section.Furthermore, since a vapor trap is not required and there is no adverse effect from it, the hydrogen concentration This provides effects such as being able to measure accurately and accurately.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional hydrogen detection device, and FIG. 2 is a partial vertical cross-sectional view of an embodiment of the hydrogen detection device according to the present invention. 30... Wall of cover gas section, 31... Flange, 32... Cylindrical container, 33... Upward flow path, 3
4... Tubular body, 35... Diffusion membrane part, 36... First
Heat source, 37...Second heat source, 38, 39...Temperature control device, 44...Hydrogen detector, 45...Sensor, 46...Detection unit controller.

Claims (1)

[Claims] 1. Provided on the wall so as to be located in the gas to be measured in the cover gas section, with a gas inlet to be measured at the bottom,
A hollow cylindrical container having a gas to be measured outlet at the top and forming an upward flow path through which the gas to be measured flows inside, a heating source that heats the gas to be measured flowing through the flow path, and this heating source. a temperature control device that adjusts and controls the amount of heating in the cylindrical container; a tubular body that is housed in the cylindrical container and has a diffusion membrane portion that transmits hydrogen contained in the gas to be measured; and a hydrogen gas connected to the tubular body. A hydrogen detection device comprising: a detector.