JPS6256456B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for detecting hydrogen contained in gas.

Liquid sodium is generally used as a coolant in fast breeder reactors. The material is further configured to exchange heat with water in a steam generator to generate steam. By the way, in this steam generator, liquid sodium and water, which are secondary coolants, are present through the walls of the heat transfer tubes, so leakage from the heat transfer tubes must be reliably prevented. For this reason, we have conventionally installed a hydrogen detection device that detects whether hydrogen is contained in the cover gas of liquid sodium, and in the event of a leak, it can detect the hydrogen produced by the reaction between sodium and water. The system is designed to enable early detection of leaks and take appropriate measures. This conventional hydrogen detection device was constructed as shown in FIG. 1 is the wall of a container containing liquid sodium and cover gas, such as a steam generator or a test tank;
A through hole 2 is formed in this wall 1, and a flange portion 3 is attached to this through hole 2. A hollow tubular body 4 is provided passing through this flange portion 3. A tubular diffusion membrane portion 5 whose lower end is closed is attached to the lower end of this tubular body 4.
The diffusion membrane portion 5 is made of a material that selectively permeates hydrogen, such as palladium, iron, nickel, etc., and is formed thin. Furthermore, a hydrogen detection mechanism 6 is connected to the upper end of the tubular body 4 . This hydrogen detection mechanism 6 has a built-in vacuum pump that evacuates the inside of the tubular body 4 and the diffusion membrane section 5 to a high vacuum, and also detects hydrogen gas that has permeated into the interior through the diffusion membrane section 5 from the cover gas. It has a built-in detector, etc. Note that 7 is a control circuit that controls this hydrogen detection mechanism 6. Further, a heater 8 is provided surrounding the diffusion film portion 5, and this heater 8 is supplied with power from a power source 9 to generate heat, heating the diffusion film portion 5 to 500°C. The structure is designed to allow hydrogen to permeate efficiently. Further, the diffusion film section 5 is provided with a temperature detector 9, and a signal from this temperature detector 9 is sent to a temperature control circuit 10.
The temperature of the diffusion film portion 5 is maintained constant by controlling the output of the power source 9. Furthermore, since the diffusion film section 5 is thin and easily damaged, a protection tube 11 is provided surrounding the diffusion film section 5 and the heater 8. Incidentally, the surface temperature of the heater 8 is generally not uniform in the axial direction or the circumferential direction, and is also affected by cover gas convection, etc., so the diffusion film portion 5 is not heated uniformly. Furthermore, since the diffusion film portion 5 is thin, the conduction of heat in the direction perpendicular to the wall thickness direction is small, so the temperature distribution of the diffusion film portion 5 is not uniform.
50℃ between the upper and lower ends of the A difference in temperature will occur. For this reason, there was a problem that the hydrogen permeability was not constant and the error became large. In addition, in such a case, a protective tube 11 must be provided surrounding the diffusion membrane section 5 and the heater 8, which increases the overall size, and the diameter of the through hole 2 formed in the wall 1 of the container must also be increased. There were some problems, such as not working properly.

The present invention has been made based on the above-mentioned circumstances, and its objectives are to make the temperature of the diffusion membrane uniform and accurate, to improve accuracy and to reduce the size of the container, and to improve the diameter of the through hole formed in the wall of the container. The object of the present invention is to obtain a hydrogen detection device that can reduce the size of the hydrogen.

The present invention will be described below with reference to an embodiment shown in FIG. In the figure, 101 is a wall of a container containing cover gas, and this wall 101 has through holes 102.
is formed. A flange portion 103 is attached to this through hole 102 to airtightly close it. A hollow tubular body 104 made of stainless steel or the like is provided to penetrate this flange portion 103. And this tubular body 10
A cylindrical radiation heating member 105 is attached to the lower end of 4. Note that this radiant heating member 105
is made of a metal material with relatively high thermal conductivity,
Moreover, its wall thickness is also relatively large. A tubular diffusion film portion 106 is accommodated within this radiation heating member 105 and concentrically therewith.
This diffusion membrane section 106 is made of a material that selectively permeates hydrogen, such as palladium, iron, nickel, etc., and is formed thin. The upper end of this diffusion membrane section 106 is closed, and the lower end thereof is open to the cover gas, so that the cover gas enters into the diffusion membrane section 106. A predetermined gap is formed between the outer peripheral surface of the diffusion film section 106 and the inner peripheral surface of the radiant heating member 105, and a gap is formed between the lower end of the diffusion film section 106 and the lower end of the radiant heating member 105. It is hermetically sealed.
Further, a cylindrical heater 107 is provided surrounding the radiation heating member 106. The heater 107 is connected to the power supply 1 through conductive wires 108 and 109 provided through the flange portion 103.
10, and is configured to be supplied with power from this power source 110 and generate heat. Further, a temperature detector 111 is installed at the upper end of the diffusion film section 106.
A signal from the temperature detector 111 is sent to a temperature control circuit 113 via a conductive wire 112 passing through the flange portion 103. The temperature control circuit 113 is configured to control the output of the power source 110 and to keep the temperature of the diffusion film portion 106 constant. Furthermore, a hydrogen detection mechanism 114 is connected to the upper end of the tubular body 104. This hydrogen detection mechanism 114 has a built-in vacuum pump (not shown) to evacuate the inside of the tubular body 104 and the radiant heating member 105 to a high vacuum. A hydrogen detector (not shown) for detecting hydrogen diffused into the body 104 is built-in. And this hydrogen detection mechanism 11
4 is configured to be automatically controlled by a control circuit 115.

In one embodiment of the present invention configured as described above, the inside of the tubular body 104 and the radiation heating member 105 are evacuated to a high vacuum by the vacuum pump built in the hydrogen detection mechanism 114, and the heater 1 is connected to the power source 110.
Electric power is supplied to the heater 107, and the heater 107 generates heat. The radiation heating member 105 is heated by the heat generated by the heater 107, and the diffusion film portion 1 is heated by the radiation heat from the radiation heating member 105.
06 is heated. Then, the cover gas flows into this diffusion membrane section 106, and the hydrogen contained therein selectively permeates through this diffusion membrane section 106 and diffuses into the radiant heating member 105 and the tubular body 104. It is detected by a hydrogen detector built into the detection mechanism 114. Since the radiant heating member 105 has a relatively large thickness and is made of a material with relatively high thermal conductivity, even if the temperature distribution of the heater 107 is uneven, the radiant heating member 105 Heat moves in the direction perpendicular to the wall thickness, and the radiant heat emitted from the radiant heating member 105 becomes uniform, so that the diffusion film portion 106 is heated uniformly and its temperature distribution is also uniform. Therefore, the hydrogen permeability of this diffusion membrane portion 106 is also accurate, and measurement accuracy is also improved. Note that this embodiment is configured so that the gap between the radiant heating member 105 and the diffusion film section 106 is a vacuum, so that no gas convection occurs within this gap.
The temperature distribution of the diffusion film portion 106 becomes more uniform. In addition, since this diffusion membrane portion 106 is surrounded by the radiation heating member 105, there is no need to provide a special protective tube, etc., and the size can be reduced, and the diameter of the through hole 102 formed in the wall 101 of the container can be reduced. can do.

Note that the present invention is applicable not only to the detection of hydrogen contained in the cover gas of a fast breeder reactor, but also to general devices for detecting hydrogen contained in other gases.

As described above, in the present invention, one end of a thin cylindrical diffusion membrane part that selectively permeates hydrogen is joined to the tip of a radiant heating member, and the other end is closed and arranged concentrically inside the radiant heating member. This is what I did. Therefore, the heat from the heater heats this radiant heating member, and the radiant heat from this radiant heating member heats the diffusion film portion. Since this radiant heating member does not need to be as thin as the diffusion film, it can be made sufficiently thick, and the temperature distribution of the heater may be somewhat uneven. The temperature distribution of this radiant heating member becomes uniform, and the radiant heat radiated from this radiant heating member also becomes uniform. Therefore, the diffusion member is heated uniformly, and the hydrogen permeability becomes accurate, so that measurement accuracy can be improved. In addition, since the thin-walled diffusion membrane is surrounded by a radiant heating member and protected from the outside, there is no need for a special protective tube, and the size can be reduced. The effect is great, as only a small diameter can be used.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional example, and FIG. 2 is a longitudinal sectional view of an embodiment of the present invention. 101...Wall, 102...Through hole, 104...Tubular body, 105...Radiation heating member, 106...Diffusion membrane portion, 107...Heater, 110...Power source,
114...Hydrogen detection mechanism.

Claims (1)

[Claims] 1 A tubular body that is inserted into the gas through a through hole formed in the wall, a cylindrical radiant heating member that is integrally provided at the tip of this tubular body, and a material that selectively transmits hydrogen, with one end a thin cylindrical diffusion membrane portion joined to the tip of the radiant heating member and disposed concentrically inside the radiant heating member with the other end closed; A hydrogen detection device comprising: a hydrogen detection mechanism that evacuates the inside of the body and detects hydrogen that has passed through the diffusion membrane; and a heater provided around the radiant heating member.