Method for testing reliability of O-shaped sealing ring for underwater isotope power supply

Abstract

The invention belongs to the technical field of material performance testing, and particularly relates to a reliability testing method of an O-shaped sealing ring for an underwater isotope power supply, which comprises the following steps of: 1, calculating the irradiation dose of the O-shaped sealing ring according to the service life of the isotope power supply; 2, manufacturing a simulation sample piece and an O-shaped sealing ring of the simulation sample piece; 3, carrying out an accelerated irradiation experiment on the O-shaped sealing ring of the simulation sample piece; 4, after irradiation is completed, sealing performance detection is conducted on the O-shaped sealing ring of the simulation sample piece; 5, carrying out pressure and sealing performance test experiments on the O-shaped sealing ring of the simulation sample piece in the high-pressure water tank; and step 6, obtaining the reliability life of the O-shaped sealing ring of the simulation sample according to the test results of the pressure and the sealing performance of the O-shaped sealing ring of the simulation sample in the high-pressure water tank. Accelerated irradiation experiments and high-pressure water tank experiments are used for accelerating simulation of the real use condition of the sealing ring, and reliability experiment data of the sealing ring are obtained to serve as a research basis.

Description

Technical Field

[0001] The invention belongs to the technical field of material performance testing, and in particular relates to a reliability testing method for an O-type sealing ring used for an underwater isotope power supply. Background Art

[0002] As a special energy device, isotope power sources are widely used in deep space, deep sea and on land. In order to prevent seawater from penetrating into the power source and causing damage to the power source during use, the underwater isotope power source adopts a radial sealing method on the power source shell structure, so the reliability of the O-ring is crucial. The isotope power source needs to work continuously for several years. The radioactive isotopes are installed inside the power source. The radiation rays generated by the radioactive isotopes will accelerate the aging of the O-ring. At the same time, the O-ring will affect its hardness and elasticity under the condition of long-term extrusion. There are many kinds of materials for rubber products on the market. In order to select the raw materials of the O-rings that can meet the design requirements, it is necessary to determine a test method to verify the reliability of the O-rings. Summary of the invention

[0003] In view of the problems existing in the prior art, the O-ring used in underwater isotope power supply has special use conditions and environment, and its long-term service status makes it impossible to effectively evaluate its reliability. The purpose of the present invention is to provide a reliability testing method for the O-ring used in underwater isotope power supply, and to evaluate the reliability of the O-ring used in underwater isotope power supply.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0005] A reliability testing method for an O-ring for an underwater isotope power supply comprises the following steps:

[0006] Step 1, calculating the radiation dose of the O-ring according to the service life of the isotope power supply;

[0007] Step 2, making a simulation sample and an O-ring of the simulation sample;

[0008] Step 3, conducting an accelerated irradiation experiment on the O-ring of the simulated sample;

[0009] Step 4: After the irradiation is completed, the O-ring of the simulated sample is tested for sealing performance;

[0010] Step 5, performing pressure and sealing test experiments on the O-ring of the simulated sample in a high-pressure water chamber;

[0011] Step 6, according to the pressure and sealing test results of the O-ring of the simulated sample in the high-pressure water chamber, the reliability life of the O-ring of the simulated sample is obtained.

[0012] Furthermore, in step 1, the irradiation dose rate of the O-ring at the position where the O-ring is located in the isotope power supply is calculated using the Monte Carlo program software MCNP, and the irradiation dose of the O-ring is obtained by multiplying the irradiation dose rate by the working time.

[0013] Furthermore, in step 2, a simulated sample and an O-ring of the simulated sample are manufactured with the same scaled-down size as the real sealing structure of the isotope power source.

[0014] Further, in step 2, when the hardness of the rubber used to make the O-ring is in the range of 10IRHD to 79IRHD, the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 25% in the radial direction; when the rubber hardness is in the range of 80IRHD to 89IRHD, the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 15% in the radial direction; when the rubber hardness is in the range of 90IRHD to 95IRHD, the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 10% in the radial direction.

[0015] Furthermore, in step 3, an appropriate position is selected to place the O-ring of the simulated sample, and the irradiation dose rate of the O-ring in the simulated sample by the radiation source used in the accelerated irradiation experiment is obtained by measuring the irradiation dose rate at the position; according to the irradiation dose result calculated in step 1, it is divided by the irradiation dose rate of the O-ring in the simulated sample by the radiation source used in the accelerated irradiation experiment to obtain the irradiation time used in the accelerated irradiation experiment.

[0016] Furthermore, in step 3, the radiation used in the accelerated irradiation experiment is of the same type as the radiation to which the O-ring is exposed in the isotope power supply, and the irradiation dose of the radiation used in the accelerated irradiation experiment to the O-ring in the simulated sample is not less than the irradiation dose calculated in step 1; the irradiation time used in the irradiation experiment is shortened by increasing the irradiation dose rate of the radiation source used in the irradiation experiment to the O-ring in the simulated sample, thereby achieving the effect of accelerated irradiation.

[0017] Further, in step 4, the O-ring of the irradiated simulation sample is assembled in the simulation sample, the simulation sample is placed in water, then taken out, the lid of the simulation sample is opened, and it is observed whether water enters the simulation sample. If water enters, it means that the sealing of the O-ring of the simulation sample has failed. If no water enters, it means that the sealing of the O-ring of the simulation sample is normal.

[0018] Further, step 5 includes the following steps:

[0019] Step 5.1, cover the lid of the simulation sample (the O-ring in the simulation sample has normal sealing performance), place the assembled simulation sample in a high-pressure water chamber, set the pressure value and pressure duration, and conduct the O-ring pressure and sealing test experiment of the simulation sample;

[0020] Step 5.2, take out the simulated sample from the high-pressure water chamber at fixed intervals, open the cover of the simulated sample, check the sealing of the O-ring of the simulated sample, and observe whether water has entered the inside of the simulated sample. If no water has entered, repeat step 5.1; if water has entered, end the O-ring pressure and sealing test experiment of the simulated sample.

[0021] Furthermore, in step 6, if water is found to have entered the simulated sample during the inspection in step 5.2, the previous test cutoff time data is used as the reliability life of the O-ring of the simulated sample.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. MCNP software can build complex physical models and simulate the required data. Compared with the traditional formula calculation method, the radiation dose value of the O-ring can be more accurately calculated by MCNP software, and there is more data support for evaluating the reliability of the O-ring;

[0024] 2. Accelerated irradiation of O-rings can shorten the time to verify the effect of radiation irradiation on the reliability of O-rings;

[0025] 3. Placing the simulated sample in a high-pressure water chamber for experiment can truly simulate the pressure on the O-ring. At the same time, checking the sealing performance of the O-ring at regular intervals can accurately obtain the reliability life data of the O-ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the radial sealing method and position of the O-ring.

[0027] Figure 2 The figure is a flow chart of the reliability test method of O-ring used in underwater isotope power supply. DETAILED DESCRIPTION

[0028] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0029] The underwater isotope power supply housing structure of the present invention is as follows Figure 1As shown, the O-ring is placed in the groove of the end cap, and the sealing method is radial static sealing. There is a radioactive source inside the isotope power supply, and the neutron rays, X-rays or gamma rays generated by it will penetrate other material structures in the isotope power supply and reach or even penetrate the O-ring. Under the condition of seawater, the entire isotope power supply will be subject to the pressure of seawater, which will affect the sealing of the O-ring.

[0030] The present invention is a reliability testing method for an O-type sealing ring for an underwater isotope power supply, comprising the following steps:

[0031] Step 1, calculating the radiation dose of the O-ring according to the service life of the isotope power supply;

[0032] Step 2, making a simulation sample and an O-ring of the simulation sample;

[0033] Step 3, conducting an accelerated irradiation experiment on the O-ring of the simulated sample;

[0034] Step 4: After the irradiation is completed, the O-ring of the simulated sample is tested for sealing performance;

[0035] Step 5, performing pressure and sealing test experiments on the O-ring of the simulated sample in a high-pressure water chamber;

[0036] Step 6, according to the pressure and sealing test results of the O-ring of the simulated sample in the high-pressure water chamber, the reliability life of the O-ring of the simulated sample is obtained.

[0037] The present invention provides a reliability testing method for an O-ring for an underwater isotope power supply. The main process is as follows: Figure 2 As shown, the method includes: (1) calculating the radiation dose of the O-ring; (2) making a simulation sample and the O-ring of the simulation sample; (3) conducting an accelerated irradiation test on the O-ring of the simulation sample; (4) conducting a sealing test on the O-ring of the simulation sample; (5) conducting a pressure and sealing test on the O-ring of the simulation sample in a high-pressure water chamber; (6) obtaining the reliability life of the O-ring of the simulation sample based on the pressure and sealing test results of the O-ring of the simulation sample in the high-pressure water chamber.

[0038] (1) Calculation of the radiation dose of the O-ring: The Monte Carlo program software MCNP is used to calculate the radiation dose rate of the O-ring at its location in the isotope power source, and the radiation dose of the O-ring is obtained by multiplying the radiation dose rate by the working time.

[0039] (2) Making simulation samples and O-rings of simulation samples: The isotope power source structure is large and heavy, which is not convenient for experimental operation. Simulation samples and O-rings of simulation samples with the same scaled-down size as the real sealing structure of the isotope power source are made to replace the isotope power source for experiments. The materials used in the simulation samples are the same as those used in the corresponding parts of the isotope power source. The size of the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 25% in the radial direction when the hardness of the rubber used to make the O-ring is within the range of 10IRHD to 79IRHD; when the hardness of the rubber is within the range of 80IRHD to 89IRHD, the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 15% in the radial direction; when the hardness of the rubber is within the range of 90IRHD to 95IRHD, the groove at the location of the O-ring of the simulation sample is designed to compress the O-ring by 10% in the radial direction.

[0040] (3) Conducting an accelerated irradiation experiment on the O-ring of the simulated sample: During the accelerated irradiation experiment, the distance between the sample placement and the radiation source will affect the radiation dose rate received by the sample. Therefore, an appropriate position is selected to place the O-ring of the simulated sample. The radiation dose rate of the radiation source used in the accelerated irradiation experiment to the O-ring in the simulated sample is obtained by measuring the radiation dose rate at this position. The irradiation dose result calculated in step 1 is divided by the radiation dose rate of the radiation source used in the accelerated irradiation experiment to the O-ring in the simulated sample to obtain the irradiation time used in the accelerated irradiation experiment. The radiation used in the accelerated irradiation experiment is of the same type as the radiation received by the O-ring in the isotope power supply (if the radiation source in the isotope power supply emits gamma rays, the radiation source in the accelerated irradiation experiment is also a radiation source that emits gamma rays; if the radiation source in the isotope power supply emits neutron rays, the radiation source in the accelerated irradiation experiment is also a radiation source that emits neutron rays, and so on). The radiation dose irradiated to the O-ring in the simulated sample by the radiation used in the accelerated irradiation experiment is not less than the radiation dose calculated in step 1; the irradiation time used in the irradiation experiment is shortened by increasing the radiation dose rate irradiated to the O-ring in the simulated sample by the radiation source used in the irradiation experiment, thereby achieving the effect of accelerated irradiation. The irradiation time obtained by dividing the radiation dose by the radiation dose rate is usually in hours, and the value is usually not an integer, but generally a decimal. In order to facilitate timing during the accelerated irradiation experiment, the irradiation time used in the actual accelerated irradiation experiment will be taken as the integer greater than the calculated irradiation time and closest to the calculated irradiation time as the irradiation time used in the accelerated irradiation experiment. In this way, the irradiation dose received by the O-ring in the simulated sample during the accelerated irradiation experiment is usually not less than the irradiation dose result received by the O-ring in the isotope power supply calculated in step 1.

[0041] (4) Conduct a sealing test on the O-ring of the simulated sample: Assemble the O-ring of the irradiated simulated sample into the simulated sample, put the simulated sample into water, take it out, open the cover of the simulated sample, and observe whether water enters the simulated sample. If water enters, it means that the sealing of the O-ring of the simulated sample fails. If no water enters, it means that the sealing of the O-ring of the simulated sample is normal.

[0042] (5) Performing pressure and sealing tests on the O-ring of the simulated sample in a high-pressure water chamber: Cover the lid of the simulated sample (the sealing of the O-ring in the simulated sample is normal), place the assembled simulated sample in the high-pressure water chamber, set the pressure value and pressure duration, and perform pressure and sealing tests on the O-ring of the simulated sample; take the simulated sample out of the high-pressure water chamber at fixed intervals, open the lid of the simulated sample, check the sealing of the O-ring of the simulated sample, and observe whether water has entered the inside of the simulated sample. If no water has entered, continue to repeat the above-mentioned experiment; if water has entered, end the pressure and sealing tests on the O-ring of the simulated sample.

[0043] (6) Based on the results of the pressure and sealing test experiments on the O-ring of the simulated sample in the high-pressure water chamber, the reliability life of the O-ring of the simulated sample is obtained: During the pressure and sealing test experiments on the O-ring of the simulated sample in the high-pressure water chamber, when water is found to have entered the simulated sample, the previous experimental cutoff time data is used as the reliability life of the O-ring of the simulated sample.

[0044] Example

[0045] Under the condition that the underwater isotope power source works for 10 years, it is calculated that the cumulative radiation dose at the location of the O-ring for 10 consecutive years is 1000Gy, and the type of radiation received is gamma rays. A certain type of fluororubber is selected as the material of the O-ring, and it is processed according to the size requirements. When performing accelerated irradiation, the selected irradiation source is Co-60, because Co-60 emits gamma rays, which is the same type of radiation received by the O-ring under working conditions. The O-ring is placed in the radiation field, and the radiation dose rate at the location where the O-ring is placed is measured to be 500Gy / h, so the accelerated irradiation time is 2 hours. After irradiation, the O-ring is placed in a simulated sample for a sealing test, put into water and then taken out, the lid is opened to observe whether water enters, if no water enters, the lid is closed again and placed in a high-pressure water chamber. The pressure of the high-pressure water chamber is set to 20MPa, and the pressurization duration is 2 hours. After the time is up, it is taken out and the lid is opened to observe whether water enters. If no water enters, the high-pressure water chamber test is continued until the O-ring fails to obtain the reliability data of the O-ring.

[0046] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A reliability testing method for an O-ring for an underwater isotope power supply, characterized in that: The following steps are involved: Step 1, calculating the radiation dose of the O-ring according to the service life of the isotope power supply; Step 2, making a simulation sample and an O-ring of the simulation sample; Step 3, conducting an accelerated irradiation experiment on the O-ring of the simulated sample; Step 4: After the irradiation is completed, the O-ring of the simulated sample is tested for sealing performance; Step 5, performing pressure and sealing test experiments on the O-ring of the simulated sample in a high-pressure water chamber; Step 6, according to the pressure and sealing test results of the O-ring of the simulated sample in the high-pressure water chamber, the reliability life of the O-ring of the simulated sample is obtained.

2. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: In step 1, the irradiation dose rate of the O-ring at the position in the isotope power supply is calculated using the Monte Carlo program software MCNP, and the irradiation dose of the O-ring is obtained by multiplying the irradiation dose rate by the working time.

3. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: In step 2, a simulated sample and an O-ring of the simulated sample are manufactured with the same scaled-down size as the real sealing structure of the isotope power source.

4. The reliability testing method of an O-ring for an underwater isotope power source according to claim 3, characterized in that: In step 2, when the hardness of the rubber used to make the O-ring is in the range of 10IRHD to 79IRHD, the groove at the location of the O-ring of the simulated sample is designed to compress the O-ring radially by 25%; when the rubber hardness is in the range of 80IRHD to 89IRHD, the groove at the location of the O-ring of the simulated sample is designed to compress the O-ring radially by 15%; when the rubber hardness is in the range of 90IRHD to 95IRHD, the groove at the location of the O-ring of the simulated sample is designed to compress the O-ring radially by 10%.

5. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: In step 3, an appropriate position is selected to place the O-ring of the simulated sample, and the irradiation dose rate of the O-ring in the simulated sample by the radiation source used in the accelerated irradiation experiment is obtained by measuring the irradiation dose rate at the position; according to the irradiation dose result calculated in step 1, it is divided by the irradiation dose rate of the O-ring in the simulated sample by the radiation source used in the accelerated irradiation experiment to obtain the irradiation time used in the accelerated irradiation experiment.

6. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: In step 3, the radiation used in the accelerated irradiation experiment is of the same type as the radiation to which the O-ring is exposed in the isotope power supply, and the irradiation dose of the radiation used in the accelerated irradiation experiment to the O-ring in the simulated sample is not less than the irradiation dose calculated in step 1; the irradiation time used in the irradiation experiment is shortened by increasing the irradiation dose rate of the radiation source used in the irradiation experiment to the O-ring in the simulated sample, thereby achieving the effect of accelerated irradiation.

7. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: In step 4, the O-ring of the irradiated simulation sample is assembled in the simulation sample, the simulation sample is placed in water, and then taken out, the lid of the simulation sample is opened, and it is observed whether water enters the simulation sample. If water enters, it means that the sealing of the O-ring of the simulation sample fails. If no water enters, it means that the sealing of the O-ring of the simulation sample is normal.

8. The reliability testing method of an O-ring for an underwater isotope power source according to claim 1, characterized in that: Step 5 includes the following steps: Step 5.1, cover the lid of the simulation sample, place the assembled simulation sample in the high-pressure water chamber, set the pressure value and pressure duration, and conduct the simulation sample O-ring pressure and sealing test experiment; Step 5.2, take out the simulated sample from the high-pressure water chamber at fixed intervals, open the cover of the simulated sample, check the sealing of the O-ring of the simulated sample, and observe whether water has entered the inside of the simulated sample. If no water has entered, repeat step 5.1; if water has entered, end the O-ring pressure and sealing test experiment of the simulated sample.

9. The reliability testing method of an O-ring for an underwater isotope power source according to claim 8, characterized in that: In step 6, if water is found to have entered the simulated sample during the inspection in step 5.2, the previous test cutoff time data is used as the reliability life of the O-ring of the simulated sample.

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