KR200167925Y1 - 1,000 ㎖ Gas Marinelli Beaker for Gamma-ray Spectrometry with Ge-detector - Google Patents

Abstract

The present invention relates to a standard container (1,000 mL M.B) for radioactive gas measurement.

Conventional radioactive measuring vessels surround the detector in a well shape, and the material is high impact polystyrene, and the standard of the container is not standardized, and the dimensional error range is also very wide, resulting in high uncertainty. Low tensile strength of the container is weak to external impact, severe deformation of the container even under normal pressure, and explosive fragility. In addition, there is a problem that it is difficult to collect a representative sample because the air in the container can not be completely discharged.

The standard container for measuring radioactivity of the present invention is coupled to the upper and lower parts of the container body by a container lid, and an O-ring is mounted therein to increase airtightness. It enters the entire bottom of the sample container and proceeds to the outlet tube to take a representative sample within a short time and to seal the sample to prevent leakage when moving or analyzing the container. Therefore, the standard container of the present invention improves safety during handling or sampling, minimizes measurement errors, and improves the detection efficiency of the detector by standardizing the standard.

Description

1,000 ml M.Ｂ standard vessel for radioactive gas measurement {1,000 ml Gas Marinelli Beaker for Gamma-ray Spectrometry with Ge-detector}

The present invention relates to a standard container (1,000 mL M.B) for radioactive gas measurement.

Conventional radiation measuring vessels are well shaped to surround the detector, and their material is high impact polystyrene, which is not standardized and has a wide range of dimensional errors. It is weak to external shocks, especially at 1.2 atm pressure, the container is severely deformed and explosive at 2 atm pressure.

In addition, the container seals the lower portion and the upper portion with an adhesive, and as a result, the adhesiveness is deteriorated and airtightness is lowered. Since the sampling tube is attached to the side, the installation space should be large, and it is inconvenient to collect the sample. Since there is no sample guide tube at the entrance of the sampling tube, the air inside the container cannot be completely discharged. it's difficult. On the other hand, because the height of the container does not fit the detector, the detection efficiency is low, the dimensional error is large and the standard is not standardized. In particular, since the cylindrical inner diameter of the well type is 78 to 84 mm, it cannot be used for a detector diameter larger than 85 mm.

Among gaseous radioactive wastes using germanium (Ge) semiconductor detectors, sample measuring vessels for radionuclide analysis and radioactivity concentrations should have low attenuation for X-rays and γ-rays. Standard containers shall have good physical properties such that the shape of the container does not deform, such as external forces, pressures, or temperatures during sampling, movement, or measurement. In particular, the standard container must have a precise capacity to ensure the reliability of the analytical results, and have a mechanical strength that does not deform the shape and volume of the container when the gas sample in the standard container is completely sealed and sampled at high pressure. Meanwhile, the shape of the standard container should be a structure that optimizes the detection efficiency of the measurement sample, and the inner surface of the standard container should be smooth and dense so that the surface adsorption of radioactive material in the sample should be minimized and the material of the container should be less affected by the background radiation during the measurement. In itself, the emission of X-rays or γ-rays should be negligibly low.

The present invention maintains measurement accuracy and radioactivity by constructing a gaseous radioactive sample in the form of 1,000 mL marinelli for high detection efficiency, collecting up to 2,000 mL of sample volume to obtain low detection limit, and collecting representative samples. In order to prevent contamination by gas, the purpose of the present invention is to provide a standard container with a structure that minimizes measurement error by improving the sealing property of the measuring container and maintaining a certain shape.

1A is a plan view of a conventional general container

Figure 1b is a cross-sectional view of a conventional general container

Figure 2a is a plan view of the standard container of the present invention

Figure 2b is a cross-sectional view of the standard container of the present invention

3 is a photograph showing a standard container of the present invention

<Explanation of symbols for the main parts of the drawings>

1: container body 2: sampling tube inlet 3: sampling tube outlet

4: Sampling guide 5: container lid 6: O-ring

7: Detector insert 8: Sampling valve

The standard container of the present invention is composed of a sampling tube inlet (2), a sampling tube outlet (3) and a sampling guide tube (4) on the upper portion of the container body (1). O-ring 6 is inserted into the container lid 5 to increase the airtightness and is combined with the container body 1. The standard container body contains the gaseous radioactive waste to be measured and safely stored and measured. Sampling tube collects representative sample within a short time by allowing gas sample to enter the entire sample container bottom through sampling tube inlet (2) and sampling tube guide tube (4) and exit to sampling outlet (3). It serves to seal the sample from leakage when moving or analyzing it.

Conventional 1000 mL measuring vessels are well shaped to surround the detector. The material is high-impact polystyrene, which is inconvenient because the inlet and outlet of the sampling tube are located on the side of the container. Very wide, with great uncertainty. The vessel's tensile strength is low, so it is vulnerable to external shocks, and especially at 1.2 atm, the shape of the vessel is severely deformed and explosive at 2 atm. The container seals the lower part and the upper part with an adhesive, and as a result, the adhesive performance is deteriorated and airtightness is lowered. The installation space should be wide because the sampling tube is located next to it, and it is inconvenient for sampling. Conventional containers are difficult to collect representative samples because there is no sample guide tube at the inlet of the sampling tube to completely discharge the air in the container during sampling. Because the height of the container does not fit the detector, the detection efficiency is low, the dimensional error is large, and the standard is not standardized, so the measurement error resulting from the difference in the container specification is relatively high. In particular, since the cylindrical inner diameter of the well type is 78 to 84 mm, it cannot be used for a detector diameter larger than 85 mm.

The present invention uses a germanium (Ge) semiconductor detector as a standard vessel of 1,000 mL Marineni type for radionuclide analysis and radioactivity concentration measurement of gaseous radioactive waste.

The 1000 mL standard gas container of the present invention has the same well shape as the conventional container, the body material is acrylonitrile-butadiene-styrene, and the lid is polycarbonate (Polycabonate), which has good mechanical strength. Stability at deformation and high pressure was ensured. The inlet and outlet of the sampling tube are located at the upper part, and the upper and lower part adopts the joining method by square screws instead of the bonding method, and an O-ring is inserted to increase the airtightness. In addition, by installing a sample guide tube at the inlet of the sampling tube to improve the flow of the sample inlet and outlet during sampling, the safety of the standard container during handling or sampling is improved, and the error caused by incorrect dimensions of the container is minimized. . The standard container adopts a sample guide tube, so that representative samples can be collected within a short time, minimizing the measurement error and filling the sample to 2 atm. Improved nuclide analysis in time. The total outer diameter of the container was 160.3 ± 0.5 mm, the height was 92.3 ± 0.2 mm, the thickness was 3.0 ± 0.3 mm, and the inside diameter of the detector was 105.8 ± 0.2 mm and the height was 73 ± 0.1 mm. Since the cylindrical inner diameter of the mold is 105.8 ± 0.2 mm, it can be used up to 102 mm, the largest detector diameter recently developed, so this standard container can be used semi-permanently when considering the progress of detector development.

<Application example>

As a result of using the standard container of the present invention in a germanium (Ge) semiconductor detector of a nuclear power plant in Korea (Gori, Yeonggwang, Wolseong, Uljin nuclear power plant), all problems of the conventional general container were solved from the field radiation analysis expert as shown in Table 1 below. .

Table 1. Container performance of the present invention

Comparison Conventional container Development container Assessment Methods Improvements By shock Breakage strength 21.59kg / cm ² 96.36kg / cm ² Use a universal tester Radiation Pollution Prevention shape transform 1.2 atmospheres ～ 5% <0.1% Of applied pressure Change measurement Improved measurement accuracy and safety 2.0 atmospheres Most explosions <0.1% Sample Leakage 1.2 Serious leakage immediately at atmospheric pressure 2 atmospheres: <1.0% (8 hours) Measurement of pressure change over time Improved measurement accuracy and safety Sampling Representative Sampling Difficult Representative Homogeneous sample can be collected Quantitative Analysis by Standard Gas Improved measurement accuracy and safety Of use convenience It is inconvenient because the collecting port is on the side In the lid Convenient to attach Field experiment Radiation safety at least Detection limit 1.0 0.5 Calculate from the formula for calculating the minimum detection limit Improve Nuclide Analysis Capability and Accuracy Detector Range of use 85mm in diameter or less 102mm in diameter or less (Semi-permanent use) See various Ge detector specifications Most Ge detectors can be applied Uncertainty <30% <3 to 5% Gamma Ray Spectroscopy Improved accuracy

Meanwhile, the description of the items of comparison is as follows.

(1) Damage due to impact: As a result of measuring the strength of the damage using the universal testing machine operated by the Institute of Standards and Science, the existing container was easily damaged at the impact of 21.59 kg / cm ² , but the developed product was not damaged even at 96.36 kg / cm ² . Only deformation of the form appeared. Therefore, the damage caused by impact was strengthened more than 5 times to prevent radiation exposure by radioactive contamination.

(2) Morphological deformation: Morphological deformation of the container affects the measurement accuracy. Therefore, as a result of increasing the pressure of the gas in the existing vessel, a severe deformation of about 5% occurred at 1.2 atm, but the developed product maintained a stable form of less than 0.1%. In addition, over 2.0% of existing vessels exploded at 2.0 atm, but only 1.0% or less of deformation occurred in the developed product.

(3) Leakage of sample: Since this container should measure gaseous radioactive sample, sealing is very important. However, the existing container is sealed by an adhesive, and thus the adhesive performance decreases with time, and thus the airtightness is deteriorated. Therefore, leakage of the sample is severe at 1.2 atm and explodes at 2 atm. However, the developed product improved the material of the container and when the gas pressure was filled up to 2 atm using the square screw type with the O-ring between the lid and the container, the leakage rate over time was measured. The rate became 1% or less of the total pressure, and it confirmed that it can use in a stable state.

(4) Sampling: The purpose of this container is to collect radioactive gas and to measure radioactivity accurately. Samples representative of the vessel should be collected quickly and in a manner. However, the sampling tube (inlet / outlet) of the existing container is located diagonally on the side, it is difficult to discharge all the air in the container even during a long sampling time. Therefore, the developed product places the sampling tube on the upper surface and installs the guide tube which can be the optimal sample flow considering the flow rate by the shape of the container so that the air can be completely discharged and the representative sample can be collected within a short time. It was. This experiment was performed by chromatographic analysis using standard gas.

(5) Convenience of use: This container should handle relatively high radioactivity and gaseous radioactive sample, so it should be easy to handle and convenient to use. Existing containers have a sampling space attached to the side, which requires a large working space and takes a lot of sampling time. The developed product has been proved through the field application that the sampling port is located on the upper surface, which reduces the use space and enables rapid sampling.

(6) Minimum detection limit, which refers to the minimum detectable radioactivity of a radiometer, the lower it is classified as a good detector. The lower the detection efficiency of the detector at the same detector and measurement time, the lower the base radiation, and the larger the amount of measurement samples. Therefore, when the measured sample volume of the existing container is 1L, the developed product can measure 2L, so the minimum detection limit can be 0.5.

(7) Range of use of detectors: Ge semiconductor detectors are currently manufactured and introduced in a large form over 100 mm in order to increase the detection efficiency from 70 mm. The well-cylinder bore diameter of the existing vessel is 84 mm and cannot be used for detector diameters larger than 85 mm. The well-cylindrical bore diameter of this development is 102 mm, which can be used for all current detectors. Therefore, standard containers can be used not only for nuclear power plants, but also for radioisotopes using institutions (academia, research institutes, medical care, industrial, etc.).

The standard vessel for measuring 1,000 mL gaseous radioactivity of the present invention improves the measurement accuracy and safety of sampling and handling of radioactivity analysis compared to general vessels. In addition, the airtightness of the container is enhanced and the measuring capability is improved. In addition, it is possible to minimize the measurement error from sampling by improving the representative sample can be taken within a short time

Claims (4)

In the radioactivity measuring container, the upper and lower portions of the container body (1) are coupled by the container lid (5) and the O-ring (6) is mounted therein to increase the airtightness. 1,000 mL MB standard container for measuring liquid radioactive waste, characterized in that the inlet (2) and the sampling guide tube (4) to enter the entire sample container bottom and discharged to the sampling outlet (3). The 1000 mL M.B standard container for radioactive waste measurement according to claim 1, wherein the container body is formed by acrylonitrile butadiene siren and the container lid is injected into a mold using polycarbonate. The 1,000 mL M.B standard container for radioactive waste measurement according to claim 1, wherein the container is a radioactive measurement standard container used for germanium (Ge) semiconductor detector nuclide analysis. The total outer diameter of the container is 160.3 ± 0.5 mm, the height is 92.3 ± 0.2 mm, the thickness is 3.0 ± 0.3 mm, and the inside diameter of the detector is 105.8 ± 0.2 mm and the height is 73 ± 0.1 mm. 1,000 mL MB standard container for radioactive waste measurement, characterized in that.