JPS5940248A - Apparatus for measuring concentrations of hydrogen and oxygen - Google Patents

Abstract

PURPOSE:To make it possible to rapidly and accurately measure concns. of H2 and O2, in an apparatus for measuring concns. of H2 and O2 in the accommodation vessel of a nuclear reactor, by arranging a moisture measuring instrument to the upstream of infrared analysers for measuring concns. of H2 and O2 while a dehumidifier is arranged to the downstream side thereof to perform compensation due to moisture. CONSTITUTION:In an H2/O2 concn. measuring apparatus for monitoring that a limit amount or more of H2 and O2 are generated in the atmosphere within the accommodation vessel of a nuclear reactor by the loss accident of the cooling material of the nuclear reactor, a non-dispersing type infrared gas analyser 10 is arranged on the way of the recirculation arranged pipe 2 from the accommodation vessel 4 to rapidly measure moisture and the drying gas from a humidifier 30 provided to the downstream side of said analyser 10 is measured by an H2-analyser 36 and an O2-analyser 38 to prevent the variation in measuring values of H2 and O2 caused by the temp. change of steam. The measuring outputs of the analysers 36, 38 are outputted to a compensator 40 to output H2 and O2 concns. compensated by the measuring signal from the analyser 10. The analyser 10 has a simple structure using a thermocouple and highly reliable and rapid and accurate measurement of H2 and O2 concns. can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for measuring the concentration of scale and oxygen contained in the atmosphere within a nuclear reactor containment vessel.

[Technical background of the invention]

Generally, in nuclear power generation facilities, consideration is given to hypothetical accidents in order to ensure the safety of the entire facility even if a hypothetical accident occurs.

One type of such hypothetical accident is a loss of coolant accident (LO
It is called CA. ) flammable gases may be generated.

This combustible gas is hydrogen and oxygen generated by the reaction between high-temperature reactor water and the zirconium alloy in the fuel cladding during TJ OCA. If the concentration exceeds a certain limit, there is a risk that the atmosphere will burn. Therefore, it is necessary to measure and monitor the hydrogen and oxygen concentrations in the atmosphere.

Therefore, the following conventional hydrogen/oxygen concentration measuring device has been used. That is, the conventional device used a galvanic cell type sensor. This galvanic cell type sensor has electrodes made of two different metals immersed in an electrolytic bath filled with different electrolytes, and a semi-permeable membrane surrounding the electrodes to allow an atmosphere to flow through the electrolyte. It was designed to let you do so. Then, hydrogen or oxygen in the atmosphere passes through the permeable membrane metal and diffuses into the electrolyte, causing an oxidation or ring element reaction and generating an electromotive force between the two electrodes. It was intended to measure concentration.

[Background technique also: Problems with j]

The conventional device has the following problems.

First, when the temperature inside the reactor containment vessel rises from the normal 50°C to about 100°C during LOCA, the diffusion characteristics of hydrogen or oxygen into the electrolyte change, causing fluctuations in measured values.

Furthermore, there was a problem in that the battery liquid expanded due to the temperature rise during LOCA and leaked from the electrolytic cell, reducing measurement accuracy.

Furthermore, it takes a certain amount of time for hydrogen or oxygen to permeate through the semipermeable membrane, resulting in a problem that the response time becomes longer.

[Purpose of the invention]

The purpose of the present invention is to increase the concentration of hydrogen and acid in the atmosphere inside the reactor containment vessel. J: An object of the present invention is to provide a hydrogen/oxygen concentration measuring device that can measure with high precision and short response times.

[Summary of the invention]

The hydrogen-oxygen concentration measuring device according to the present invention is provided with a circulation pipe that communicates with the reactor containment vessel, and a pump is completely inserted in the middle of this circulation pipe, and before measuring the hydrogen/oxygen concentration, A moisture measuring section for suppressing moisture 'fc' in the atmosphere is inserted into the circulation piping, a dehumidifier is inserted downstream of the moisture measuring section, and a hydrogen/oxygen enriched section upper measuring section is inserted downstream of the dehumidifier. The apparatus is equipped with a measuring section and a measuring section for correcting and outputting these measured values based on the signal from the moisture measuring section.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 to 3. Reference numeral 2 in FIG. 1 is a circulation pipe that communicates with the inside of the reactor containment vessel 4. This circulation pipe 2 is configured to lead out the entire atmosphere inside the reactor containment vessel 4 to the outside and circulate it back into the reactor containment vessel 4. A pump 6.8 is inserted in the middle of the circulation pipe 4. Further, a non-dispersive infrared analyzer 10, which is a moisture measuring section, is inserted in the middle of the circulation pipe 2, and is configured to measure the moisture tt in the atmosphere.

The analyzer 10 measures the amount of moisture in the atmosphere before measuring the hydrogen and oxygen concentrations, and corrects the measured values of hydrogen and oxygen, which will be described later.

Further, 11 is an on-off valve, and 12 is a solenoid valve.

The analyzer 10 will be explained with reference to FIGS. 2 and 3. 14 in FIG. 2 is a sample cell, and this sample cell 14
It is constructed so that the entire atmosphere passes through it. The sample cell 14 is provided with a through hole 9 perpendicular to the direction of flow of the atmosphere 5-, and an interference filter 16 is attached to this through hole. This interference filter 16 is installed in the center of the sample cell 14, as shown in FIG. A light source 18 that emits infrared rays is provided above the interference filter 16, and an AC power source 20 is connected to this light source 18.

A concave mirror 22 is installed above the light source 18;
The sample cell 1 as a fully parallel infrared beam from a light source 18
It is configured to irradiate 4. A concave mirror 24 for condensing light is installed below the interference filter 16, and is configured to condense infrared light m transmitted through the interference filter 16 onto a thermocouple 26. thermocouple 26
changes the electromotive force according to changes in the focused infrared light,
It is configured to output as a measurement signal of moisture in the atmosphere.

A dehumidifier 30 is inserted in the circulation pipe 2 downstream of the analyzer 10, and is configured to remove moisture 6- from the atmosphere. The moisture condensed in the dehumidifier 3o is temporarily stored in a drain tank 32 and then discharged to a drain recovery tank. Also, 34
is an on-off valve.

A pump 6 and a pressure regulating valve 32 are inserted downstream of the dehumidifier 30, and are configured to maintain the pressure within the circulation pipe 2 constant.

A pressure gauge 34 is connected to the downstream side of the pressure regulating valve 32 and is configured to monitor the pressure within the circulation pipe 2.

A hydrogen meter 36 and an oxygen meter 38 are inserted downstream of the pressure gauge 34 to measure the hydrogen and oxygen concentrations in the dehumidified atmosphere in order to stabilize the measured values, and convert the measured signals into a corrector 40.
is configured to output to. The moisture measurement signal from the analyzer 10 is transmitted to this corrector 4o, and the measurement signals from the hydrogen meter 36 and oxygen meter 38 are corrected and outputted as the concentration of water and oxygen in the atmosphere before dehumidification. It is configured. These hydrogen meter 36, oxygen meter 38, and corrector 4o form a measuring section 42.

A flow meter 44 and a back pressure regulating valve 46 are inserted downstream of the measuring section 42. Further, an on-off valve 48 is provided on the downstream side of the pump 8, and is configured to circulate the entire atmosphere into the reactor containment vessel 4.

In addition, 50 in the figure is a calibration gas supply pipe p1 solenoid valve 5
2'fr: It is configured to open and close to allow calibration gas to flow through the circulation pipe 5o.

The effects of the device configured as above will be explained.

First, before measuring the hydrogen-oxygen concentration, the moisture in the atmosphere was removed using a dehumidifier 3o, so the water vapor mixed in the atmosphere, which is the sample to be measured, was removed, and the hydrogen and oxygen caused by temperature changes in the water vapor were removed. Fluctuations in the measured concentration values can be prevented, and hydrogen and oxygen concentrations can be measured accurately.

Then, the corrector 40 corrects the amount of water removed from the atmosphere and outputs it as a measurement result of the hydrogen/oxygen concentration, allowing even more accurate measurement.

Further, since the atmosphere sampled from inside the reactor containment vessel 4 is directly measured by the hydrogen meter 36 and the oxygen meter 38, the response time is short and rapid measurement can be performed.

Furthermore, a non-dispersive infrared analyzer 10 is used as a moisture measuring section, and since the analyzer 10 obtains a detection signal with a thermocouple 26, it has a simple structure and can perform highly reliable moisture measurements.

〔Effect of the invention〕

According to the present invention, the hydrogen and oxygen concentrations in the atmosphere inside the reactor containment vessel can be measured with high accuracy and in a short response time.
The effect is great.

[Brief explanation of drawings]

1 to 3 are diagrams showing one embodiment of the present invention, in which FIG. 1 is an overall configuration diagram, FIG. 2 is a configuration diagram showing a non-dispersive infrared analyzer 10 as a moisture measuring section, and FIG. The figure is I in Figure 2.
-1 arrow view. 4... Reactor containment vessel, 2... Circulation piping, 6, 8.
...Pump, 1o...Non-dispersive infrared analyzer (moisture 9
- Measuring part), 30... Dehumidifier, 36... Hydrogen meter (measuring part), 38... Oxygen meter (measuring part), 4o... Corrector (measuring part). Applicant's agent Patent attorney Takehiko Suzue 10-

Claims (1)

[Claims] (1) A circulation pipe that communicates with the reactor containment vessel and takes out the atmosphere inside the vessel to the outside and circulates it, a pump inserted in the middle of this circulation pipe, and a pump inserted in the middle of the circulation pipe. a moisture measuring section that continuously measures moisture in the atmosphere and outputs a moisture measurement signal; a dehumidifier inserted downstream of the moisture measuring section; and a dehumidifier inserted downstream of the dehumidifier. vi: Equipped with a measuring section that measures water volume and oxygen concentration, corrects and outputs these measured values based on the moisture measurement signal from the moisture measuring section! Water volume-acid cumulative concentration measurement device for mold. (Odor) The hydrogen/oxygen concentration measuring device according to claim (1), wherein the moisture measuring section is a non-dispersive infrared gas analyzer.