Real-time estimation method of personnel radiation dose based on I-131 and Co-60 concentration monitoring in the air

Abstract

The present invention discloses a real-time estimation method for personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air. The method estimates the internal radiation dose of personnel based on real-time measured data of I-131 and Co-60 activity concentrations. Furthermore, the method converts and accumulates the external radiation dose monitoring results to estimate the total radiation dose of personnel in real time. This method not only meets the real-time requirements but also enables instant correction based on the measured data, thereby improving the prediction accuracy. Therefore, the radiation dose received by personnel can be minimized, the probability of random effects can be reduced, and deterministic effects can be prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation dose estimation, and in particular to a method for real-time estimation of personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air. Background Art

[0002] In the event of a nuclear power plant accident, assessors are required to promptly assess and estimate exposure doses. This provides a basis for personnel protection during rescue and response operations, allowing the development of effective and targeted protective measures. Following a nuclear accident, on-site workers and the public outside the plant are primarily exposed through external immersion and internal inhalation, with inhalation often being the primary route of exposure. While nuclear power plant personnel are equipped with thermoluminescence or direct-reading personal dosimeters that can measure external doses, internal doses lack real-time measurement methods and rely primarily on dose estimation. This presents challenges for real-time control of doses to personnel during an accident.

[0003] To address the above technical issues, those skilled in the art pre-calculated and determined the accident process, setting a conservative accident process sequence and a relatively high radionuclide release ratio, to calculate the exposure dose to personnel in the workplace during the accident, and based on this, developed a personnel exposure dose management plan. However, the technical problems with this approach are that, first, the prediction results of personnel internal exposure dose cannot be obtained a priori or verified in real time, and can only be determined through post-incident testing; second, for complex workplaces, the analysis and prediction results of this plan have limited coverage, and cannot adapt to situations where radiation levels fluctuate significantly due to sudden deterioration of the accident. It is also impossible to measure and intervene in the real-time exposure dose to personnel, which makes it easy for personnel to be over-exposed. Summary of the Invention

[0004] To address the above technical problems, the present invention provides a method for real-time estimation of personnel radiation dose based on monitoring I-131 and Co-60 concentrations in the air. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is provided below. This summary is not intended to be a comprehensive review, identify key or important elements, or delineate the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simplified form, serving as a prelude to the detailed description that follows.

[0005] The present invention adopts the following technical solutions:

[0006] The present invention provides a method for real-time estimation of personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air, comprising:

[0007] Establish a database;

[0008] Obtain the accident type and reactor burnup depth at the accident site;

[0009] Inputting the acquired accident type and reactor burnup depth into an established database to obtain contribution data, wherein the contribution data includes the I-131 internal exposure dose contribution rate, the Co-60 internal exposure dose contribution rate, and the total internal exposure dose contribution rate;

[0010] Calculate the real-time internal exposure dose of radioactive materials to personnel during the operation period;

[0011] The total dose is calculated based on the calculated real-time internal exposure dose of personnel and the above-mentioned proportion data.

[0012] Furthermore, the process of calculating the real-time internal exposure dose of radioactive substances to personnel during the operation period includes:

[0013] Determine whether the fuel element is damaged;

[0014] If the result is damaged, the I-131 instantaneous activity concentration monitoring data C in the air of the workplace is obtained. I-131 (t), and calculate the real-time internal exposure dose E of I-131 at time t according to the following formula: I-131 (t,i):

[0015]

[0016] In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X I-131 is the dose conversion factor;

[0017] If the result is that it is not damaged, the instantaneous activity concentration monitoring data of Co-60 in the air in the workplace C is obtained. Co-60 (t), and calculate the real-time internal exposure dose E of Co-60 at time t according to the following formula: Co-60 (t,i):

[0018]

[0019] In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X Co-60 is the dose conversion factor.

[0020] Furthermore, the process of calculating the total dose based on the calculated real-time personnel internal exposure dose and the proportion data includes:

[0021] If the result is damage, the total internal radiation dose Q2 is calculated according to the following formula:

[0022]

[0023] In the above formula, f2 is the proportion of I-131 internal radiation dose;

[0024] If the result is that there is no damage, the total internal radiation dose Q2 is calculated according to the following formula:

[0025]

[0026] In the above formula, f3 is the proportion of Co-60 internal irradiation dose.

[0027] Furthermore, the process of calculating the total dose based on the calculated real-time personnel internal exposure dose and the proportion data also includes:

[0028] Determine whether personnel are wearing dosimeters;

[0029] If the result is to wear a dosimeter, read the dosimeter to obtain the total external exposure dose Q3, then according to the formula Q4 = Q2 + Q3 or the formula Calculate the total dose Q4;

[0030] If the result is that the dosimeter is not worn, then according to the formula Calculate the total dose Q4;

[0031] Among them, f1 is the proportion of the total internal radiation dose.

[0032] The beneficial effects brought about by the present invention are as follows: The present invention estimates the internal radiation dose of personnel based on the real-time measured data of I-131 and Co-60 activity concentrations, which not only meets the real-time requirements but also enables instant correction based on the measured data, thereby improving the prediction accuracy. Therefore, it can minimize the radiation dose of personnel, reduce the probability of random effects, and prevent the occurrence of deterministic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 The figure is a flow chart of a method for real-time estimation of personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air according to the present invention. DETAILED DESCRIPTION

[0035] The following describes embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0036] like Figure 1 As shown, the present invention provides a method for real-time estimation of personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air, comprising the following steps:

[0037] 101: Create a database.

[0038] Based on an analysis of different nuclear accident sequences and the radiation consequences for personnel in typical pressurized water reactors, the internal radiation dose to personnel in the workplace contributes the most to the total dose. Furthermore, the internal radiation dose to personnel caused by inhalation of I-131 when the fuel elements are damaged and Co-60 when the fuel elements are intact are the main contributors.

[0039] While the causes of nuclear power plant accidents are inexhaustible, the types of accidents are limited. Typical examples include plant-wide power outages, primary circuit rupture and water loss, and steam generator heat transfer tube failure. Under the same type of accident, the release ratio of various radionuclides remains roughly constant, and the percentage of internal exposure doses to personnel caused by typical radionuclides remains roughly constant. Therefore, it is possible to conduct pre-analysis and establish a database.

[0040] The database contains contribution data for different accident types and reactor burnup depths, including the I-131 internal exposure dose contribution rate f2, the Co-60 internal exposure dose contribution rate f3, and the total internal exposure dose contribution rate f1.

[0041] Specifically, f1 refers to the ratio of the total dose of internal radiation inhaled by personnel to the total dose. The total dose generally refers to the sum of the total dose of internal radiation inhaled and the total dose of external radiation.

[0042] f2 refers to the proportion of the internal radiation dose inhaled by personnel caused by the release of I-131 into the air in the workplace when the fuel element is damaged, which accounts for the total internal radiation dose inhaled by personnel.

[0043] f3 refers to the proportion of the internal exposure dose inhaled by personnel caused by Co-60 released into the air in the workplace when the fuel elements are not damaged, which accounts for the total internal exposure dose inhaled by personnel.

[0044] Based on the design of nuclear power plant reactors and typical nuclear accident sequences, and using deterministic safety analysis methods in the nuclear power field, and based on the typical burnup moments of nuclear power plant reactors, the results of radionuclide releases under typical accident types, and the doses to personnel, a real-time prediction model can be obtained by sorting out f1, f2, and f3 under each case. That is, a database can be pre-analyzed and established that can show the contribution rates of I-131 and Co-60 to internal exposure doses to personnel under different accident types and different reactor burnup depths.

[0045] 102: Obtain the accident type and reactor burnup depth at the accident site.

[0046] I-131 and Co-60 concentration monitoring instruments are deployed in places where personnel are required to work to measure the activity concentration of I-131 and Co-60 in Bq / m 3 Most nuclear power plants are designed to install I-131 and Co-60 concentration monitoring instruments at key work sites.

[0047] 103: Input the currently acquired accident type and reactor burnup depth into the established database to obtain the percentage data.

[0048] 104: Calculate the real-time internal exposure dose Q1 of radioactive substances to personnel during the operation period.

[0049] The process of step 104 includes:

[0050] 1041: Determine whether the fuel element is damaged.

[0051] 1042: If the result is damaged, obtain the I-131 instantaneous activity concentration monitoring data C in the air in the workplace I-131 (t).

[0052] 1043: Assume that radioactive material is released into the workplace at time t0 after the accident, and the workers are in the workplace from time t1 to time t, integrate the instantaneous activity concentration, and calculate the real-time internal exposure dose E of I-131 at time t according to the following formula: I-131 (t,i):

[0053]

[0054] In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X I-131 is the dose conversion factor. I-131 (t,i) is Q1.

[0055] 1044: If the result is that it is not damaged, obtain the instantaneous activity concentration monitoring data of Co-60 in the air in the workplace C Co-60 (t).

[0056] 1045: Assume that radioactive material is released into the workplace at time t0 after the accident, and the workers are in the workplace from time t1 to time t, integrate the instantaneous activity concentration, and calculate the real-time internal exposure dose E of Co-60 at time t according to the following formula: Co-60 (t,i):

[0057]

[0058] In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X Co-60 is the dose conversion factor. Co-60 (t,i) is Q1.

[0059] 105: Calculate the total dose Q4 based on the calculated real-time personnel internal exposure dose Q1 and proportion data.

[0060] Step 105 includes:

[0061] 1051: Calculate the total internal radiation dose Q2.

[0062] If the result of step 1041 is damage, the total internal radiation dose Q2 is calculated according to the following formula:

[0063]

[0064] In the above formula, f2 is the ratio of I-131 internal radiation dose; E I-131 (t,i) is the real-time internal exposure dose of I-131 to personnel at time t.

[0065] If the result of step 1041 is that the device is not damaged, the total internal radiation dose Q2 is calculated according to the following formula:

[0066]

[0067] In the above formula, f3 is the ratio of Co-60 internal irradiation dose; E Co-60 (t,i) is the real-time internal exposure dose of Co-60 to personnel at time t.

[0068] 1052: Determine whether the personnel are wearing a dosimeter. Dosimeter refers to a thermoluminescent or direct-reading personal dosimeter.

[0069] 1053: If the judgment result is to wear a dosimeter, read the dosimeter to obtain the total external exposure dose Q3.

[0070] 1054: According to the formula Q4 = Q2 + Q3 or the formula Calculate the total dose Q4, where f1 is the proportion of the total internal irradiation dose.

[0071] 1055: If the result is that the dosimeter is not worn, then according to the formula Calculate the total dose Q4.

[0072] Under the existing technical solutions, only the external radiation dose of personnel can be monitored, and the internal radiation dose of personnel can only be estimated in advance and measured afterwards. It cannot be corrected based on the actual measured data, and the analysis and prediction accuracy is poor.

[0073] The present invention estimates internal radiation doses in real time based on the monitoring results of I-131 and Co-60 nuclides in ambient air. By adding these to the external radiation dose monitoring results through a simple conversion relationship, the total radiation dose is estimated in real time. This not only meets real-time requirements and has a wide range of applications, but also enables instant correction based on measured data, thereby improving prediction accuracy. This minimizes the radiation dose received by personnel, reduces the probability of stochastic effects, and prevents the occurrence of deterministic effects. Therefore, the present invention can closely monitor changes in personnel doses during nuclear power plant accidents, accurately and timely predict changes in personnel doses, and formulate emergency plans for personnel rescue and disposal accordingly.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for real-time estimation of personnel radiation dose based on monitoring of I-131 and Co-60 concentrations in the air, characterized in that: include: Establish a database; Obtain the accident type and reactor burnup depth at the accident site; Inputting the acquired accident type and reactor burnup depth into an established database to obtain contribution data, wherein the contribution data includes the I-131 internal exposure dose contribution rate, the Co-60 internal exposure dose contribution rate, and the total internal exposure dose contribution rate; Calculating the real-time internal exposure dose of radioactive materials to personnel during the operation period. The process of calculating the real-time internal exposure dose of radioactive materials to personnel during the operation period includes: Determine whether the fuel element is damaged; If the result is damaged, the I-131 instantaneous activity concentration monitoring data C in the air of the workplace is obtained. I-131 (t), and calculate the real-time internal exposure dose E of I-131 at time t according to the following formula: I-131 (t,i): In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X I-131 is the dose conversion factor; If the result is that it is not damaged, the instantaneous activity concentration monitoring data of Co-60 in the air in the workplace C is obtained. Co-60 (t), and calculate the real-time internal exposure dose E of Co-60 at time t according to the following formula: Co-60 (t,i): In the above formula, I is the breathing rate of personnel, unit is m 3 / s;X Co-60 is the dose conversion factor; The total dose is calculated based on the calculated real-time personnel internal exposure dose and the aforementioned proportion data. The process includes: if the judgment result is damage, the total internal exposure dose Q2 is calculated based on the following formula: In the above formula, f2 is the proportion of I-131 internal radiation dose; If the result is that there is no damage, the total internal radiation dose Q2 is calculated according to the following formula: In the above formula, f3 is the proportion of Co-60 internal radiation dose; Determine whether personnel are wearing dosimeters; If the result is to wear a dosimeter, read the dosimeter to obtain the total external exposure dose Q3, then according to the formula Q4 = Q2 + Q3 or the formula Calculate the total dose Q4; If the result is that the dosimeter is not worn, then according to the formula Calculate the total dose Q4; Among them, f1 is the proportion of the total internal radiation dose.

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