A method for measuring the radiation dose on the surface of uranium on line

Abstract

The application relates to a method for measuring the radiation dose of a uranium surface on line, which is based on two detectors, a processing unit and a display unit, the two detectors are symmetrically arranged at the same height on the two sides of a rotating screw rod and are installed side by side above the uranium surface to be measured, the responses of an A detector and a B detector to gamma rays are consistent, the A detector and the B detector are in communication with the processing unit, the processing result of the processing unit is displayed on the display unit, the A detector is used to detect the uranium surface to be measured, the contribution M1 of the beta rays and the gamma rays emitted by the uranium surface to be measured to the A detector is obtained, the B detector is used to detect the uranium surface to be measured, the contribution M2 of the gamma rays emitted by the uranium surface to the B detector is obtained, and the dose value of the combined action of the beta rays and the gamma rays in the measured place is determined according to M1 and M2. The method disclosed in the application can measure the dose generated by the mixed radiation of beta rays and gamma rays on the uranium surface on line, and can provide a reliable basis for the decision of the radiation protection action.

Description

Technical Field

[0001] This invention belongs to the field of radiation monitoring, specifically relating to a method for online measurement of radiation dose on the surface of uranium. Background Technology

[0002] For uranium fuel 238 U and 235 Both uranium and uranium nuclides emit high-energy beta rays with maximum energies of 0.51 MeV, 1.10 MeV, 1.16 MeV, 1.29 MeV, 1.37 MeV, 1.43 MeV, and 3.28 MeV during their continuous decay, accompanied by gamma rays of approximately 130 keV and 180 keV. As uranium is used as fuel in nuclear reactors and nuclear weapons, personnel in close proximity to uranium in facilities such as fuel element manufacturing plants and reprocessing plants may still experience significant doses of radiation exposure to their extremities and skin.

[0003] Therefore, radiation dose monitoring is necessary for locations where uranium is present to assess the weak penetrating radiation exposure to workers. However, uranium emits both beta and gamma rays, and currently there are no instruments that can accurately measure the radiation dose from a mixture of beta and gamma radiation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for online measurement of uranium surface radiation dose, applicable to uranium surface radiation in uranium fuel production, storage, and use sites. Real-time dosage monitoring can be applied to the uranium surface throughout the entire process from uranium mining to uranium fuel briquetting. Dosage measurement.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for online measurement of uranium surface radiation dose, the method being based on an online uranium surface radiation dose measurement system, the system comprising an A detector, a B detector, a rotating screw, a processing unit, and a display unit. The A detector and the B detector are respectively positioned at the same height on both sides of the rotating screw, and are mounted side-by-side above the uranium surface to be measured. The A detector is used to measure the dose rate contributed by beta rays and gamma rays emitted by the uranium; the B detector is used to measure the dose rate of gamma rays emitted by the uranium; the A detector and the B detector have identical responses to gamma rays; both the A detector and the B detector communicate with the processing unit, and the processing results of the processing unit are displayed on the display unit. The method includes the following steps:

[0007] S1. The entrance window of detector A is aligned with the surface of the uranium to be tested, and the surface of the uranium to be tested is detected. The β and γ rays emitted by the surface of the uranium to be tested are observed together at detector A. Contribution M1;

[0008] S2. Rotate the rotating screw 180 degrees to exchange the positions of detector A and detector B. Align the entrance window of detector B with the surface of the uranium to be measured, ensuring that the sensitive volume position of detector B coincides with the sensitive volume position of detector A during measurement in step S1. Detector B then probes the surface of the uranium to be measured, obtaining the gamma rays emitted by the uranium surface and their effect on detector B. Contribute M2;

[0009] S3, according to detector A Contributing to the M1 and B detectors Contribution M2 determines the combined effect of β-rays and γ-rays at the test site. Dosage value.

[0010] Furthermore, a beta-ray absorbing material was installed at the front end of the B detector to absorb all beta rays emitted by uranium, allowing only gamma rays to be incident on the sensitive volume of the B detector.

[0011] Furthermore, step S3 includes the following sub-steps:

[0012] S31, using detector B The contribution M2 is multiplied by the calibration factor Nγ of the gamma rays emitted by the B detector for uranium, and then multiplied by the attenuation correction factor Ns of the gamma rays by the β-ray absorbing material installed in the front window of the B detector, to accurately obtain the gamma ray level of the measured uranium-emitted gamma rays. Contribution value

[0013]

[0014] S32. Subtract the product of M2 and Ns from M1 to obtain the contribution value M3 of β rays to detector A.

[0015] S33. Multiply M3 by the calibration factor N for the beta rays emitted by detector A for uranium. β To obtain the β-ray response at the test site Contribution value

[0016] S34, according to and The value determines the combined effect of beta and gamma rays at the test site. Dosage value.

[0017] Furthermore, in step S33, the calibration factor N for the β-rays emitted by detector A for uranium... β Take detector A at 90 Sr- 90 Calibration factor in the Y standard radiation field.

[0018] Furthermore, in step S34 and Adding them together yields the combined effect of beta and gamma rays at the test site. value.

[0019] Furthermore, in step S34, the display unit monitors the data for each cycle. and The value is displayed.

[0020] Furthermore, according to and The ratio of beta radiation to gamma radiation at the test site is used to assess the effect of beta radiation on gamma radiation. The contribution relationship of values.

[0021] Furthermore, the method also includes pre-setting a rotation frequency to periodically rotate detector A and detector B, thereby continuously measuring and obtaining the values ​​of M1 and M2.

[0022] Furthermore, the thickness range of the β-ray absorbing material is 1 g / cm. 2 ~2g / cm 2 .

[0023] Furthermore, beta-ray absorbing materials include plexiglass and aluminum.

[0024] The beneficial technical effects of this invention are as follows: based on the simultaneous emission of β-rays and γ-rays by uranium, the β-radiation emitted from the uranium surface has high energy and a high radiation dose rate, and part of the β-radiation from the uranium surface is effective against... The contribution of beta and gamma radiation can be two orders of magnitude higher than that of gamma radiation. To assess the weak penetrating radiation experienced by personnel at uranium-containing radiation sites, a monitoring system with dual detectors was used to monitor the mixed radiation of beta and gamma radiation on the uranium fuel surface online. Dosage measurement and high dose rate alarms provide a reliable basis for radiation protection decisions. Radiation protection professionals will assess the situation based on the location... Based on dose measurement values, reasonable and feasible protective measures should be taken to reduce the risk of weak penetrating radiation dose and skin burns to radiation workers. Attached Figure Description

[0025] Figure 1 This is the monitoring system upon which the method for online measurement of uranium surface radiation dose shown in Embodiment 1 of the present invention is based. Detailed Implementation

[0026] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] This invention provides a method for online measurement of uranium surface radiation dose, such as... Figure 1 As shown, the method is based on an online system for measuring the radiation dose on a uranium surface. The system includes an A detector, a B detector, a processing unit, and a display unit. Detectors A and B are respectively positioned on opposite sides of a rotating screw and are mounted side-by-side above the surface of the uranium fuel to be measured. Detector A is used to measure the dose rate contributed by all beta and gamma rays emitted by the uranium; detector B is used to measure the dose rate of gamma rays emitted by the uranium.

[0029] Detectors A and B exhibit essentially identical responses to beta and gamma rays, meaning that the dose rate values ​​measured by the two detectors in the same gamma and / or beta radiation fields are substantially equal. Before the window thickness of detector B was increased, detectors A and B had identical structures, both used for measuring... Targeted dose equivalent rate.

[0030] The only difference between detector B and detector A is that detector B has a 1g / cm thickness installed at its front end. 2 ~2g / cm 2 Materials with low density, such as plexiglass and aluminum, are used to absorb all the beta rays emitted by uranium, allowing only gamma rays to be incident on the sensitive volume of the beta detector.

[0031] The signals measured by detectors A and B are transmitted to the processing unit. After analysis and processing, the β contribution of the uranium surface can be obtained. Numerical value, gamma contribution Numerical values, and the combined contribution of β and γ rays. Numerical value.

[0032] The method includes the following steps:

[0033] S1. The entrance window of detector A is aligned with the surface of the uranium to be tested, and the surface of the uranium to be tested is detected. The β and γ rays emitted by the surface of the uranium to be tested are observed together at detector A. Contribute M1.

[0034] S2. Rotate the rotating screw 180 degrees to exchange the positions of detector A and detector B. Align the entrance window of detector B with the surface of the uranium to be measured, ensuring that the sensitive volume position of detector B coincides with the sensitive volume position of detector A during measurement in step S1. Detector B then probes the surface of the uranium to be measured, obtaining the gamma rays emitted by the uranium surface and their effect on detector B. Contribute M2.

[0035] To continuously monitor radiation dose, detectors A and B need to be rotated periodically to continuously measure and obtain the values ​​of M1 and M2. The rotation frequency for each detection cycle needs to be preset in the system. For example, after detector A measures for 1 minute, detector B is rotated to the same position and measured for 1 minute, and so on, rotating and measuring repeatedly.

[0036] S3, according to detector A Contributing to the M1 and B detectors Contribution M2 determines the combined effect of β-rays and γ-rays at the test site. Dosage value.

[0037] Step S3 includes the following sub-steps:

[0038] S31, Processing unit uses detector B The contribution is M2 multiplied by the calibration factor Nγ of the gamma rays emitted by the B detector for uranium, and then multiplied by the thickness of the front window mounting, which is 1 g / cm. 2 ~2g / cm 2 The attenuation correction factor Ns of γ-rays using materials such as plexiglass and aluminum is used to accurately obtain the attenuation factor Ns of the γ-rays emitted by the measured uranium. Contribution value

[0039] S32. The processing unit subtracts the product of M2 and Ns from M1 to obtain the contribution value M3 of β-rays to detector A.

[0040] S33, the processing unit multiplies M3 by the calibration factor N of the β-rays emitted by detector A for uranium. β It can accurately obtain the β-ray response at the test site. Contribution value

[0041] Because the β energy range of uranium emission is related to 90 Sr- 90 The β energies emitted by Y are similar, therefore, the calibration factor N β Detector A can be taken at 90 Sr- 90 Calibration factor in the Y standard radiation field.

[0042] S34, and By adding them together, the common values ​​of β-rays and γ-rays at the test site can be accurately given. Value; based on and The ratio of β radiation to γ ​​radiation at the test site can be used to assess the effect of β radiation on the test site. The contribution relationship of values.

[0043] The display unit monitors each cycle simultaneously. and The value is displayed.

[0044] As can be seen from the above embodiments, the method for online measurement of uranium surface radiation dose disclosed in this invention can measure the mixed β and γ radiation generated on the uranium surface online. Dosage measurements provide a reliable basis for decision-making in radiation protection actions.

[0045] The method described in this invention is not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of technical innovation of this invention.

Claims

1. A method for online measurement of uranium surface radiation dose, the method being based on a system for online measurement of uranium surface radiation dose, the system comprising an A detector, a B detector, a rotating screw, a processing unit, and a display unit, wherein the A detector and the B detector are respectively disposed at the same height on both sides of the rotating screw, the A detector and the B detector are mounted side by side above the uranium surface to be measured, the A detector is used to measure the dose rate contributed by β-rays and γ-rays emitted by uranium; the B detector is used to measure the dose rate of γ-rays emitted by uranium, the A detector and the B detector have consistent responses to γ-rays; both the A detector and the B detector communicate with the processing unit, the processing result of the processing unit is displayed on the display unit, the method comprising the following steps: S1. The entrance window of detector A is aligned with the surface of the uranium to be tested, and the surface of the uranium to be tested is detected. The β and γ rays emitted by the surface of the uranium to be tested are observed together at detector A. Contribution M1; S2. Rotate the rotating screw 180 degrees to exchange the positions of detector A and detector B. Align the entrance window of detector B with the surface of the uranium to be measured, ensuring that the sensitive volume position of detector B coincides with the sensitive volume position of detector A during measurement in step S1. Detector B then probes the surface of the uranium to be measured, obtaining the gamma rays emitted by the uranium surface and their effect on detector B. Contribute M2; S3, according to detector A Contributing to the M1 and B detectors Contribution M2 determines the combined effect of β-rays and γ-rays at the test site. Dosage value.

2. The method for online measurement of uranium surface radiation dose as described in claim 1, characterized in that: A beta-ray absorbing material was installed at the front end of the B detector to absorb all beta rays emitted by uranium, allowing only gamma rays to enter the sensitive volume of the B detector.

3. The method for online measurement of uranium surface radiation dose as described in claim 2, characterized in that, Step S3 includes the following sub-steps: S31, using detector B The contribution M2 is multiplied by the calibration factor Nγ of the uranium-emitted gamma rays from the B detector, and then multiplied by the attenuation correction factor Ns of the gamma rays from the beta-ray absorbing material installed in the front window of the B detector, to obtain the gamma ray level of the measured uranium-emitted gamma rays. Contribution value S32. Subtract the product of M2 and Ns from M1 to obtain the contribution value M3 of β rays to detector A. S33. Multiply M3 by the calibration factor N for the beta rays emitted by detector A for uranium. β To obtain the β-ray response at the test site Contribution value S34, according to and The value determines the combined effect of beta and gamma rays at the test site. Dosage value.

4. The method for online measurement of uranium surface radiation dose as described in claim 3, characterized in that: The calibration factor N of the A detector for the beta rays emitted by uranium in step S33 β The calibration factor N of the A detector for the beta rays emitted by uranium in step S33 90 Sr- 90 Y standard radiation field.

5. The method for online measurement of uranium surface radiation dose as described in claim 3, characterized in that: In step S34 and Adding them together yields the combined effect of beta and gamma rays at the test site. value.

6. The method for online measurement of uranium surface radiation dose as described in claim 5, characterized in that: In step S34, the display unit monitors the data for each cycle. and The value is displayed.

7. The method for online measurement of uranium surface radiation dose as described in claim 3, characterized in that: according to and The ratio of β radiation to γ ​​radiation at the test site is used to assess the effect of β radiation on the test site. The contribution relationship of values.

8. The method for online measurement of uranium surface radiation dose as described in claim 3, characterized in that: The method also includes pre-setting a rotation frequency to periodically rotate detector A and detector B, thereby continuously measuring and obtaining the values ​​of M1 and M2.

9. The method for online measurement of uranium surface radiation dose as described in claim 2, characterized in that: The thickness range of the β-ray absorbing material is 1 g / cm. 2 ~2g / cm 2 .

10. The method for online measurement of uranium surface radiation dose as described in claim 2, characterized in that: Beta-ray absorbing materials include plexiglass and aluminum.

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