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Online detection device and method for sodium aerosol in air

A detection device and a technology of sodium gas are applied in the field of reactors, which can solve the problems of high energy consumption of laser sources, increase of fire danger sources, large flow of sampling gas, etc., and achieve the effect of low energy consumption

Pending Publication Date: 2019-10-11
CHINA INSTITUTE OF ATOMIC ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

As a conventional fire detector, smoke detectors respond to all smoke including sodium aerosols, and cannot distinguish sodium fires from conventional fires; sodium ionization detectors are mainly used in smoke containing sodium aerosols in inert gases Detection, this is because other components in the air will also ionize when the sample gas is discharged, which will affect the accuracy of detection; the differential pressure detector measures the pressure difference before and after the sample gas passes through the filter device, this method responds slowly and has Delay, and the required sample gas flow rate is large; none of the above methods is specifically for the detection of sodium aerosols, and none of them can achieve early sodium leakage detection
Flame furnace atomization detectors generally use organic gas combustion flames to atomize the sampled gas, and measure the concentration of sodium in the gas by measuring the intensity of the characteristic spectral line of sodium, which can achieve early detection of sodium leakage, but the introduction of Organic gases add an additional source of fire hazard, which poses a great potential safety hazard. In the early French Phoenix reactor, this method was adopted as the main method and detection method for the early detection of LBB sodium leakage. However, with the increasing requirements for nuclear safety, due to the introduction of this method Organic gas increases the risk of other fires and gradually fades out of use. So far, there is no better method and measurement method to replace this method; the laser detector uses high-energy laser pulses to dissociate the sampled gas to form a high-temperature plasma state. Analyzing the intensity of the characteristic spectral line of sodium during the plasma cooling process, and obtaining the concentration information of sodium element, can realize early sodium leakage detection, but the laser source consumes a lot of energy, and it is not easy to run stably for a long time, so it cannot realize online continuous operation monitoring

Method used

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  • Online detection device and method for sodium aerosol in air
  • Online detection device and method for sodium aerosol in air
  • Online detection device and method for sodium aerosol in air

Examples

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Embodiment 1

[0041] The sampling and splitting device 2 in this embodiment uses the pump 1 to sample the sample air in the area to be measured, with a sampling flow rate of 10 L / min, and then splits the collected large-flow samples into the working gas, and then enters the plasma at the same time Inside the torch, it is excited by the plasma flame to produce an atomic emission spectrum.

[0042] Atomic emission spectroscopy excitation source B. In order to realize real-time online detection, it is usually a plasma device that can work stably for a long time. In this embodiment, a stable and reliable low-power microwave plasma is used as the excitation source. The working principle of microwave plasma can be simply described as: the microwave power source generates microwave power, which is fed into the microwave torch through a coaxial cable, and the working gas source argon absorbs the microwave energy. At this time, the ignition device generates seed electrons, and the plasma rapidly Ge...

Embodiment 2

[0054] This embodiment is the same as Embodiment 1, the difference is that the stainless steel inner tube of the microwave plasma torch of the triple concentric tube structure adopted in the present embodiment is 2mm outer diameter, 0.3mm wall thickness, and the copper middle tube is 7mm outer diameter. Diameter, 0.8mm wall thickness, copper outer tube is 27mm outer diameter, 2mm wall thickness;

[0055] The microwave working power is between 100W and the working gas flow rate is between 600mL / min.

[0056] Utilize the above-mentioned method to concentration be 50ppb, the Na of 75ppb + / H 2 O standard samples are detected, and the detection results are as follows image 3 shown.

Embodiment 3

[0058] This embodiment is the same as Embodiment 1, the difference is that the stainless steel inner tube of the microwave plasma torch of the triple concentric tube structure adopted in the present embodiment is 3mm outer diameter, 0.4mm wall thickness, and the copper middle tube is 8mm outer diameter. Diameter, 1.0mm wall thickness, copper outer tube is 26mm outer diameter, 1.5mm wall thickness;

[0059] The microwave working power is between 200W and the working gas flow rate is between 1000mL / min.

[0060] Utilize the above-mentioned method to the Na concentration that is 100ppb + / H 2 O standard samples are detected, and the detection results are as follows image 3 shown.

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Abstract

The invention belongs to the technical field of reactors, and particularly relates to an online detection device and method for sodium aerosol in reactor air. The device comprises a sampling and shunting device, an atomic emission spectroscopy excitation source, a spectral monitoring device and a correction bottle, wherein the sampling and shunting device conveys an air sample to the atomic emission spectroscopy excitation source; the atomic emission spectroscopy excitation source excites an atomic emission spectroscopy from sodium aerosol in the air sample and collects the atomic emission spectroscopy through the spectral monitoring device; the spectral monitoring device separates out sodium atomic emission light and converts the sodium atomic emission light into an electric signal; and the correction bottle provides an aerosol sample with a known concentration for the atomic emission spectroscopy excitation source. The online detection device and method for the sodium aerosol in thereactor air are stable in operation for a long time, low in energy consumption and low in detection limit.

Description

technical field [0001] The disclosure belongs to the technical field of reactors, and in particular relates to an online detection device and method for sodium aerosol in the air of a reactor. Background technique [0002] Fast neutron reactors use liquid metal sodium as the coolant. Under normal circumstances, high-temperature sodium is in containers and pipes, and it will not burn in contact with air. When an accident causes damage to pipelines or equipment, high-temperature liquid sodium may leak into the air and burn. Sodium combustion will cause serious damage to equipment and room structures, and generate a large amount of harmful sodium aerosols. Therefore, how to realize the early and accurate detection of sodium leakage is one of the key problems that need to be solved in the detection of sodium fire, so as to provide a more important guarantee for the safety of fast reactors. [0003] The devices and methods currently used in the detection of sodium aerosols in t...

Claims

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Application Information

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IPC IPC(8): G01N21/73
CPCG01N21/73
Inventor 杜海鸥周培德段忆翔朴君申凤阳谢淳王荣东王国芝石文涛韩新梅
Owner CHINA INSTITUTE OF ATOMIC ENERGY