A control body radioactive source term calculation method and device and evaluation method

Abstract

The application discloses a kind of control body's radioactive source item calculation method, device and evaluation method, the calculation method includes: when the state of control body is outside circulation operation, and inside circulation is simultaneously operated, the concentration of nuclide in control body loop is calculated according to the parameter of outside circulation and inside circulation simultaneously operating;And when the state of control body is outside circulation closed, and inside circulation is operated, the concentration of nuclide in control body loop is calculated according to inside circulation operating parameter.The application provides a general method for calculating the radioactive source item of containment, water tank and plant ventilation system and multiple control bodies, unifies the calculation mathematical model of nuclide activity, simultaneously considers the influence of two generation sub-nuclear decay and considers the influence of dynamic balance, and the method can be used to calculate and analyze the activity concentration of radioactive nuclide under different conditions in each process loop.

Description

Technical Field

[0001] This invention relates to nuclear power technology, and more specifically to a method, apparatus, and evaluation method for calculating the radioactive source term of a control body. Background Technology

[0002] In a pressurized water reactor (PWR) nuclear power plant, the main coolant absorbs the heat released from nuclear fuel fission in the reactor core. This heat is then transferred to the secondary loop via a steam generator to produce steam, which in turn powers a turbine to drive a generator. During nuclear fuel fission, radioactive nuclides are generated and transported through the process loops to auxiliary systems, waste treatment systems, and leak into the containment. Nuclear power plant safety analyses and environmental assessments require calculations of radiation shielding, emissions of gaseous and liquid effluents, and assessments of public and biological radiation environmental impacts. These analyses must include the calculation and analysis of the activity concentrations of radioactive nuclides transported, accumulated, and emitted in each process loop.

[0003] However, in the current technology, there is no source term calculation method specifically for the characteristics of existing pressurized water reactor nuclear power plants, nor is there a universal calculation method that can be used for multiple control bodies such as the source terms of the containment, water tank, and plant ventilation system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies of the prior art by providing a method, apparatus and evaluation method for calculating the radioactive source terms of a control body, so as to provide a general method for calculating the radioactive source terms of multiple control bodies such as containment vessels, water tanks and plant ventilation systems.

[0005] In a first aspect, the present invention provides a method for calculating the radioactive source term of a control body. The method is applied to a control body, which includes an inner circulation structure and an outer circulation structure. The inner circulation structure forms an inner circulation within the control body, and the outer circulation structure includes a control body inlet and a control body outlet, which together form an outer circulation outside the control body. The state of the inner circulation within the control body includes an inner circulation running state and an inner circulation closed state, and the state of the outer circulation outside the control body includes an outer circulation running state and an outer circulation closed state.

[0006] The method includes:

[0007] When the control body is in the state of external circulation operation and internal circulation operation at the same time, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the external circulation and internal circulation of the control body at the same time.

[0008] as well as,

[0009] When the control body is in a state where the outer circulation is closed and the inner circulation is running, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the inner circulation during the operation of the control body.

[0010] Furthermore, when the control body is in the state of external circulation operation and internal circulation operation simultaneously, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the external circulation and internal circulation of the control body operating simultaneously. Specifically, this includes calculating the concentration of the nuclide in the control body loop according to any one of the following conditions A1, A2, or A3:

[0011] A1: If nuclide m enters the control volume container directly, calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0012]

[0013] In formula (1):

[0014] g represents the inlet flow velocity at the control volume inlet. The activity concentration of the upstream nuclide of nuclide m. Let m be the fraction of nuclide m entering the control volume from the inlet medium, G be the circulation velocity, F be the outlet velocity, V be the control volume, and β be the volume of the control volume. m Here, t represents the time it takes for the container to enter the control body, and t represents the time it takes for the container to enter the control body.

[0015] First intermediate process quantity β m The calculation formula is as follows:

[0016]

[0017] In formula (2):

[0018] ε m Where G is the circulating filtration efficiency, F is the circulating flow rate, and λ is the outlet flow rate. m Let m be the decay constant of nuclide m.

[0019] A2: If nuclide m is derived from the decay of nuclide m-1 or nuclide m-2, and nuclide m-1 is the parent nuclide of nuclide m, and nuclide m-2 is the parent nuclide of nuclide m-1, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0020]

[0021] In formula (3),

[0022] For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0023] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0024]

[0025]

[0026]

[0027] ε m-k For the cyclic filtration efficiency of the mk nuclide, λ m-k Let mk be the decay constant of the nuclide mk;

[0028] A3: If nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0029]

[0030] In formula (7) This is the fourth intermediate process quantity, and the formula for calculating the fourth intermediate process quantity is as follows:

[0031]

[0032] β m-k In this case, k takes the value 1 or 2.

[0033] Furthermore, when the control body is in a state where the external circulation is closed and the internal circulation is running, the concentration of the nuclide in the control body loop is calculated based on the operating parameters during the internal circulation of the control body. Specifically, this includes calculating the concentration of the nuclide in the control body loop based on any one of the following conditions B1, B2, or B3:

[0034] B1: If nuclide m decays directly, calculate the concentration of nuclide m in the control loop. The formula is as follows:

[0035]

[0036] In formula (9):

[0037] Let β be the initial concentration of nuclide m in the control volume loop. m This is the quantity for the first intermediate process;

[0038] First intermediate process quantity β m The calculation formula is as follows:

[0039]

[0040] In formula (10):

[0041] ε m For the circulating filtration efficiency, λ m Let be the decay constant of nuclide m, G be the circulation velocity, F be the outlet velocity, and V be the control volume.

[0042] B2: If nuclide m is derived from the decay of nuclide m-1 or nuclide m-2, and nuclide m-1 is the parent nuclide of nuclide m, and nuclide m-2 is the parent nuclide of nuclide m-1, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0043]

[0044]

[0045] In formula (11),

[0046] For m-nuclide deposition fraction, λ represents the proportion of mk parent nuclei that decay into m nuclides. m-k Let mk be the decay constant of the nuclide mk. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0047] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0048]

[0049]

[0050] in:

[0051]

[0052] In formula (14):

[0053] ε m-k For the cyclic filtration efficiency of the mk nuclide, λ m-k Let be the decay constant of nuclide mk, where k takes the value 1 or 2;

[0054] B3: If nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0055]

[0056] In formula (15):

[0057] The proportion of m-nuctoplasm entering the control medium from the inlet medium. According to formula (13).

[0058] Furthermore, when the control body is a containment ventilation system, the circulation filtration efficiency ε is obtained based on the type of radioactive gas and the parameters of the containment. m The inlet flow velocity g, outlet flow velocity F, circulation flow velocity G, and m-nucleoside deposition fraction of the control volume inlet. The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes:

[0059]

[0060] In formula (16):

[0061] When the radioactive gas is an inert gas, the circulation filtration efficiency ε m The efficiency ε is 0 when the radioactive gas is iodine. m The circulating filtration efficiency ε is 0.999 when the radioactive gas is an aerosol. m It is 0.99;

[0062] g = D1; F = D2; G = D3; (17)

[0064] In formula (17):

[0065] The inlet velocity g of the control body inlet is the inflow flow rate D1 of the containment, the outlet velocity F is the outflow flow rate D2 of the containment, and the circulation velocity G is the circulation flow rate D3 of the containment.

[0066]

[0067] In formula (18):

[0068] m-nucleoside deposition fraction =1;

[0069]

[0070] In formula (19):

[0071] When the radioactive gas is an inert gas, the proportion of nuclide m entering the control body from the inlet medium. Let k1 be the fraction of nuclide m that enters the control medium from the inlet medium when the radioactive gas is iodine. For k2, when the radioactive gas is an aerosol, the fraction of nuclide m entering the control medium from the inlet medium is k2. Let k3 be the volatile factor, where k1, k2, and k3 are all volatile factors.

[0072] Furthermore, when the control body is a water tank ventilation system, the inlet flow velocity g, outlet flow velocity F, circulation flow velocity G, and m-nucleoside deposition fraction of the control body are obtained based on the type of radioactive gas and the parameters of the containment. The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes:

[0073] g = D1; G = F = 0 (20)

[0075] In formula (20):

[0076] The inlet velocity g of the control body is the inflow flow rate D1 of the water tank, and the outlet velocity F and the circulation velocity G are both zero;

[0077]

[0078] In formula (21):

[0079] When the radioactive gas is an inert gas, the m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. Both are c1. When the radioactive gas is iodine, the m-nuclide deposition fraction is... The proportion of m-nuclides entering the control body from the inlet medium. Both are c2. When the radioactive gas is an aerosol, the deposition fraction of the m nuclide is... The proportion of m-nuclides entering the control body from the inlet medium. All are c3, where c1, c2 and c3 are all sedimentation factors.

[0080] Furthermore, when the control body is a factory ventilation system, the inlet velocity g, outlet velocity F, circulation velocity G, and m-nucleoside deposition fraction of the control body are obtained based on the type of radioactive gas and the parameters of the factory ventilation system. The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes:

[0081] g = D1; G = F = 0 (twenty two)

[0083] In formula (22):

[0084] The inlet velocity g at the control body inlet is the inflow flow rate D1 of the plant ventilation system, and the outlet velocity F and the circulation velocity G are both zero;

[0085]

[0086] In formula (23):

[0087] m-nucleoside deposition fraction =1;

[0088]

[0089] In formula (24):

[0090] When the radioactive gas is an inert gas, the proportion of nuclide m entering the control body from the inlet medium. For K1, when the radioactive gas is iodine, the proportion of nuclide m entering the control medium from the inlet medium. For K2, when the radioactive gas is an aerosol, the fraction of nuclide m entering the control medium from the inlet medium. All are K3, where k1, k2 and k3 are all volatile factors.

[0091] Secondly, the present invention provides a device for calculating the radioactive source term of a control body.

[0092] The device is used to calculate the radioactive source term of a control body, which includes an inner circulation structure and an outer circulation structure. The inner circulation structure forms an inner circulation within the control body, and the outer circulation structure includes a control body inlet and a control body outlet, which together form an outer circulation outside the control body. The state of the inner circulation within the control body includes an inner circulation running state and an inner circulation closed state, and the state of the outer circulation outside the control body includes an outer circulation running state and an outer circulation closed state.

[0093] The device includes a first computing unit and a second computing unit connected in parallel.

[0094] The first calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the external circulation and the internal circulation of the control body when the control body is in the state of external circulation operation and internal circulation operation.

[0095] The second calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the control body during the internal loop operation when the external loop is closed and the internal loop is running.

[0096] Furthermore, the first computing unit includes a first computing module, a second computing module, and a third computing module connected in parallel.

[0097] The first calculation module is used to calculate the concentration of nuclide m in the control body loop when nuclide m enters the container directly into the control body.

[0098] Calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0099]

[0100] In formula (25):

[0101] g represents the inlet flow velocity at the control volume inlet. The activity concentration of the upstream nuclide of nuclide m. Let m be the fraction of nuclide m entering the control volume from the inlet medium, G be the circulation velocity, F be the outlet velocity, V be the control volume, and β be the volume of the control volume. m The first intermediate process quantity is t, where t is the time it takes to enter the container of the control body.

[0102] First intermediate process quantity β m The calculation formula is as follows:

[0103]

[0104] In formula (26):

[0105] ε m For the circulating filtration efficiency, λ m Let m be the decay constant of nuclide m.

[0106] The second calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is derived from the decay of nuclide m-1 or nuclide m-2.

[0107] Nuclide m-1 is the parent nuclide of nuclide m, and nuclide m-2 is the parent nuclide of nuclide m-1. The concentration of nuclide m in the control loop... The calculation formula is as follows:

[0108]

[0109]

[0110] In formula (27),

[0111] For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0112] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0113]

[0114]

[0115]

[0116] ε m-kLet λ be the circulating filtration efficiency of nuclide mk, G be the circulating flow rate, F be the outlet flow rate, and λ be the filtration efficiency. m-k Let mk be the decay constant of the nuclide mk;

[0117] The second calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m.

[0118] Concentration of nuclide m in the control loop The formula is as follows:

[0119]

[0120] In formula (31) This is the fourth intermediate process quantity, and the formula for calculating the fourth intermediate process quantity is as follows:

[0121]

[0122] β m-k In this case, k takes the value 1 or 2.

[0123] Furthermore, the second computing unit includes a fourth computing module, a fifth computing module, and a sixth computing module connected in parallel.

[0124] The fourth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m decays directly. Concentration of nuclide m in the control loop The calculation formula is as follows:

[0125]

[0126] In formula (33):

[0127] Let β be the initial concentration of nuclide m in the control volume loop. m This is the quantity for the first intermediate process;

[0128] First intermediate process quantity β m The calculation formula is as follows:

[0129]

[0130] In formula (34):

[0131] ε m For the circulating filtration efficiency, λ m Let be the decay constant of nuclide m, G be the circulation velocity, F be the outlet velocity, and V be the control volume.

[0132] The fifth calculation module is used to calculate the concentration of nuclide m in the control volume loop, since nuclide m-1 is the parent nuclide of nuclide m-1 and nuclide m-2 is the parent nuclide of nuclide m-1.

[0133] Concentration of nuclide m in the control loop The formula is as follows:

[0134]

[0135] In formula (35),

[0136] For m-nuclide deposition fraction, λ represents the proportion of mk parent nuclei that decay into m nuclides. m-k Let mk be the decay constant of the nuclide mk. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0137] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0138]

[0139]

[0140] in:

[0141]

[0142] In formula (38):

[0143] ε m-k For the cyclic filtration efficiency of the mk nuclide, λ m-k Let be the decay constant of nuclide mk, where k takes the value 1 or 2;

[0144] The sixth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m.

[0145] Concentration of nuclide m in the control loop The calculation formula is as follows:

[0146]

[0147] In formula (39):

[0148] The proportion of m-nuctoplasm entering the control medium from the inlet medium. According to formula (37).

[0149] Thirdly, the present invention provides a method for evaluating the radioactive source term of a control body, the method comprising the steps of:

[0150] Using the aforementioned method for calculating the radioactive source term of the control system, the active concentrations of radionuclides transported, accumulated, and emitted in each process loop are obtained.

[0151] Determine whether the active concentration is less than a preset threshold, and determine the radiation impact based on the determination result: if the determination result is yes, determine that the active concentration meets the radiation requirements; if the determination result is no, determine that the active concentration does not meet the radiation requirements.

[0152] Beneficial effects achieved:

[0153] (1) This invention provides a general method for calculating the radioactive source terms of multiple control bodies such as containment structures, water tanks, and plant ventilation systems;

[0154] (2) This invention unifies the mathematical model for calculating nuclide activity, while taking into account the effects of two generations of daughter nuclei decay and the effects of dynamic equilibrium.

[0155] (3) This invention has a wide range of applications and can be used to calculate the activity accumulation and emission of radionuclides in the containment, water tank and plant ventilation system of nuclear power units under normal operation, expected operating events and accident conditions; it can also be used to calculate and analyze the activity concentration of radionuclides transported, accumulated and emitted in each process loop.

[0156] (4) This invention provides a method for evaluating radioactive source terms to determine whether the activity concentration meets radiation requirements;

[0157] (5) The calculation results obtained according to the present invention are widely used in radiation shielding, emission source terms and accident emergency response, and are also the basis for public and biological radiation environmental impact assessment, providing technical support for plant site capacity and plant site license application. Attached Figure Description

[0158] Figure 1 This is the general nuclide accumulation dynamic equilibrium mathematical model in the embodiments of the present invention;

[0159] Figure 2 This is a physical model for the dynamic equilibrium of nuclide accumulation in the containment structure in this embodiment of the invention;

[0160] Figure 3 The radioactive source term calculation device is the control body in the embodiment of the present invention.

[0161] In the diagram, the labels are: I - inlet velocity, F - outlet velocity, G - circulation system velocity, and ε. m - Circulation system filtration efficiency, V- Control volume. Detailed Implementation

[0162] To enable those skilled in the art to better understand the technical solution of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0163] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0164] It is understood that, without conflict, the various embodiments and features in the embodiments of the present invention can be combined with each other.

[0165] It is understood that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, while the parts unrelated to the present invention are not shown in the drawings.

[0166] It is understood that each unit or module involved in the embodiments of the present invention may correspond to only one entity structure, or may be composed of multiple entity structures, or multiple units or modules may be integrated into one entity structure.

[0167] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of this invention may occur in a different order than that marked in the accompanying drawings.

[0168] It is understood that the flowcharts and block diagrams of this invention illustrate the possible architecture, functions, and operations of systems, apparatuses, devices, and methods according to various embodiments of this invention. Each block in the flowchart or block diagram may represent a unit, module, program segment, or code, containing executable instructions for implementing the specified function. Furthermore, each block or combination of blocks in the block diagram and flowchart can be implemented using a hardware-based system to achieve the specified function, or using a combination of hardware and computer instructions.

[0169] It is understood that the units and modules involved in the embodiments of the present invention can be implemented by software or by hardware. For example, the units and modules can be located in a processor.

[0170] When the inventors filed this application, they had studied single-line type of double busbar connection, single-line type of double busbar connection with reserved expansion bay, and double-break isolation of busbar disconnect switch:

[0171] Example 1:

[0172] like Figure 1 and Figure 2 As shown in the figure, this embodiment provides a method for calculating the accumulation and emission of radionuclides in the containment, water tank, and plant ventilation system during normal operation and accident conditions of a pressurized water reactor.

[0173] During the operation of a nuclear power plant, the inflow rate of most process loop components is constant. The concentration of nuclides in the process loop components is mainly determined by 1) the inflow of nuclides and their decay; 2) the decay of the parent nuclide and the next generation parent nuclide; 3) the decay of the next generation parent nuclide to the parent nuclide, and then the decay of the parent nuclide.

[0174] Nuclide m enters the container directly.

[0175]

[0176] make:

[0177]

[0178]

[0179] A m Let m be the activity concentration of nuclide m in the process loop assembly, and g be the inlet flow rate. This refers to the activity concentration of the upstream nuclide. Let m be the fraction of nuclide m entering the control volume from the inlet medium, G be the circulation velocity, F be the outlet velocity, and ε be the circulatory velocity. m For the circulating filtration efficiency, λ m Let be the decay constant of nuclide m, and V be the volume of the container.

[0180] Nuclide m is derived from the decay of nuclide m-1 and nuclide m-2.

[0181]

[0182] make:

[0183]

[0184]

[0185]

[0186] For m-nuclide deposition fraction, This represents the proportion of mk parent nuclei that decay into m nuclides.

[0187] Nuclide m is derived from the decay of nuclide m-2 → m-1 → m.

[0188]

[0189] make:

[0190]

[0191]

[0192] Stagnation phase, where the inlet flow rate is zero:

[0193] nuclide m decay

[0194]

[0195] make:

[0196]

[0197]

[0198] Nuclide m is derived from the decay of nuclide m-1 and nuclide m-2.

[0199]

[0200] make:

[0201]

[0202]

[0203]

[0204] Nuclide m is derived from the decay of nuclide m-2 → m-1 → m.

[0205]

[0206]

[0207] Assume the following flow velocities are known:

[0208] D1 Inflow rate, L / h

[0209] D2 outflow rate, L / h

[0210] D3 circulation flow rate, L / h

[0211] Therefore, the activity concentrations in the containment vessel, water tank, and plant ventilation system are:

[0212] 1) Containment

[0213] Assume that the primary loop leakage velocity is constant, the specific activity of the leaking medium is constant, and the ventilation and filtration system is operating.

[0214]

[0215] g = D1; F = D2; G = D3;

[0216]

[0217]

[0218] 2) Water tank (pre-storage tank for waste liquid treatment system)

[0219] Assume that water is injected to the control line, the inflow velocity is constant, and the specific activity of the inflow medium is constant;

[0220] g = D1; G = F = 0

[0221]

[0222] c j Deposition factor, j = 1, 2 or 3;

[0223] 3) Factory ventilation system

[0224] Assuming the leakage rate is constant and the specific activity of the leaking medium is constant, the iodine adsorber and the high-efficiency particle filter will stop operating.

[0225] g = D1; G = F = 0

[0226]

[0227]

[0228] k j Volatile factors;

[0229] This is a conservative estimate, as there are no relevant experiments to establish empirical parameters for the precipitation and spraying processes of nuclides.

[0230] Example 2:

[0231] like Figure 1 and Figure 3 As shown, this embodiment provides a device for calculating the radioactive source term of a control body.

[0232] This device is used to calculate the radioactive source term of a control body. The control body includes an inner circulation structure and an outer circulation structure. The inner circulation structure forms the inner circulation of the control body, and the outer circulation structure includes a control body inlet and a control body outlet. The control body inlet and control body outlet form the outer circulation of the control body. The state of the inner circulation of the control body includes an inner circulation running state and an inner circulation closed state. The state of the outer circulation of the control body includes an outer circulation running state and an outer circulation closed state.

[0233] The device includes a first computing unit and a second computing unit connected in parallel.

[0234] The first calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the external circulation and the internal circulation of the control body when the control body is in the state of external circulation operation and internal circulation operation.

[0235] The second calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the control body during the internal loop operation when the external loop is closed and the internal loop is running.

[0236] Specifically, the first computing unit includes a first computing module, a second computing module, and a third computing module connected in parallel.

[0237] The first calculation module is used to calculate the concentration of nuclide m in the control body loop when nuclide m enters the container directly into the control body.

[0238] Calculate the concentration of nuclide m in the control volume loop. The formula is as follows:

[0239]

[0240] In formula (40):

[0241] g is the inlet flow velocity at the control volume inlet. The activity concentration of the upstream nuclide of nuclide m. Let m be the fraction of nuclide m entering the control volume from the inlet medium, G be the circulation velocity, F be the outlet velocity, V be the control volume, and β be the volume of the control volume. m Here, t represents the first intermediate process quantity, and t represents the time it takes for the container to enter the control body.

[0242] First intermediate process quantity β m The calculation formula is as follows:

[0243]

[0244] In formula (41):

[0245] ε m For the circulating filtration efficiency, λ m Let m be the decay constant of nuclide m.

[0246] The second calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is derived from the decay of nuclide m-1 or nuclide m-2.

[0247] Nuclide m-1 is the parent nuclide of nuclide m, and nuclide m-2 is the parent nuclide of nuclide m-1. The concentration of nuclide m in the control volume loop... The calculation formula is as follows:

[0248]

[0249] In formula (42),

[0250] For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0251] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0252]

[0253]

[0254]

[0255] ε m-k Let λ be the circulating filtration efficiency of nuclide mk, G be the circulating flow rate, F be the outlet flow rate, and λ be the filtration efficiency. m-k Let mk be the decay constant of the nuclide mk;

[0256] The second calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m.

[0257] Concentration of nuclide m in the control loop The formula is as follows:

[0258]

[0259] In formula (31) This is the fourth intermediate process quantity, and the formula for calculating the fourth intermediate process quantity is as follows:

[0260]

[0261] β m-k In this case, k takes the value 1 or 2.

[0262] Specifically, the second computing unit includes a fourth computing module, a fifth computing module, and a sixth computing module connected in parallel.

[0263] The fourth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m decays directly. Concentration of nuclide m in the control loop The calculation formula is as follows:

[0264]

[0265] In formula (33):

[0266] Let β be the initial concentration of nuclide m in the control volume loop. mThis refers to the quantity used in the first intermediate process.

[0267] First intermediate process quantity β m The calculation formula is as follows:

[0268]

[0269] In formula (34):

[0270] ε m For the circulating filtration efficiency, λ m Let be the decay constant of nuclide m, G be the circulation velocity, F be the outlet velocity, and V be the control volume.

[0271] The fifth calculation module is used to calculate the concentration of nuclide m in the control volume loop, since nuclide m-1 is the parent nuclide of nuclide m-1 and nuclide m-2 is the parent nuclide of nuclide m-1.

[0272] Concentration of nuclide m in the control loop The formula is as follows:

[0273]

[0274] In formula (50),

[0275] For m-nuclide deposition fraction, λ represents the proportion of mk parent nuclei that decay into m nuclides. m-k Let mk be the decay constant of the nuclide mk. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2;

[0276] The formulas for calculating the quantities of the second and third intermediate processes are as follows:

[0277]

[0278]

[0279] in:

[0280] In formula (53):

[0281] ε m-k For the cyclic filtration efficiency of the mk nuclide, λ m-k Let be the decay constant of nuclide mk, where k takes the value 1 or 2;

[0282] The sixth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m.

[0283] Concentration of nuclide m in the control loop The calculation formula is as follows:

[0284]

[0285] In formula (54):

[0286] The proportion of m-nuctoplasm entering the control medium from the inlet medium. According to formula (52).

[0287] Both Examples 1 and 2 provide general methods for calculating radioactive source terms in multiple control bodies, including containment vessels, water tanks, and plant ventilation systems. Both Examples 1 and 2 unify the mathematical models for calculating nuclide activity, considering the effects of two generations of nuclear decay and dynamic equilibrium. Both Examples 1 and 2 are widely applicable, capable of calculating the activity accumulation and emissions of radionuclides in containment vessels, water tanks, and plant ventilation systems under normal operation, anticipated operating events, and accident conditions. They can also be used to calculate and analyze the activity concentrations of radionuclides transported, accumulated, and emitted in various process loops. Both Examples 1 and 2 provide methods for assessing radioactive source terms to determine whether the activity concentration meets radiation requirements. The calculation results obtained from Examples 1 and 2 are widely used in radiation shielding, emission source terms, and accident emergency response, and also serve as the basis for public and biological radiation environmental impact assessments, providing technical support for site capacity and site license applications.

[0288] Example 3:

[0289] Based on the same technical concept as in Embodiment 1, this embodiment provides a method for evaluating the radioactive source term of a control body, the evaluation method comprising the following steps:

[0290] Using the radioactive source term calculation method of the control body in Example 1, the active concentrations of radionuclides transported, accumulated, and emitted in each process loop were obtained.

[0291] Determine whether the active concentration is less than a preset threshold, and determine the radiation impact based on the determination result: if the determination result is yes, determine that the active concentration meets the radiation requirements; if the determination result is no, determine that the active concentration does not meet the radiation requirements.

[0292] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for calculating the radioactive source term of a control volume, characterized in that, The control body includes an inner circulation structure and an outer circulation structure. The inner circulation structure forms an inner circulation within the control body, and the outer circulation structure includes a control body inlet and a control body outlet. The control body inlet and control outlet form an outer circulation outside the control body. The state of the inner circulation within the control body includes an inner circulation running state and an inner circulation closed state, and the state of the outer circulation outside the control body includes an outer circulation running state and an outer circulation closed state. The method includes: When the control body is in the state of external circulation operation and internal circulation operation at the same time, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the external circulation and internal circulation of the control body at the same time. as well as, When the control body is in a state where the outer circulation is closed and the inner circulation is running, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the inner circulation during the operation of the control body. When the control body is in the state of external circulation operation and internal circulation operation simultaneously, the concentration of the nuclide in the control body loop is calculated based on the operating parameters of the external circulation and internal circulation of the control body operating simultaneously. Specifically, this includes calculating the concentration of the nuclide in the control body loop according to any one of the following conditions A1, A2, or A3: A1: If nuclide m enters the control volume container directly, calculate the concentration of nuclide m in the control volume loop. The formula is as follows: (1) In formula (1): To control the inlet flow velocity at the body inlet, The activity concentration of the upstream nuclide of nuclide m. The proportion of m-nuctoplasm entering the control medium from the inlet medium. Here, t represents the time it takes for the container to enter the control body, and t represents the time it takes for the container to enter the control body. First intermediate process quantity The calculation formula is as follows: (2) In formula (2): For circulation filtration efficiency, For circulation flow rate, For export flow rate, To control the volume, Let m be the decay constant of nuclide m. A2: If nuclide m is derived from the decay of nuclide m-1 or nuclide m-2, and nuclide m-1 is the parent nuclide of nuclide m, and nuclide m-2 is the parent nuclide of nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows: (3) In formula (3), For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2; The formulas for calculating the quantities of the second and third intermediate processes are as follows: (4) （5） (6) The cyclic filtration efficiency of mk nuclides. Let mk be the decay constant of the nuclide mk; A3: If nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows: （7） In formula (7) This is the fourth intermediate process quantity, and the formula for calculating the fourth intermediate process quantity is as follows: （8） In this context, k takes the value 1 or 2; When the control body is in a state where the external circulation is closed and the internal circulation is running, the concentration of the nuclide in the control body loop is calculated based on the operating parameters during the internal circulation of the control body. Specifically, this includes calculating the concentration of the nuclide in the control body loop based on any one of the following conditions B1, B2, or B3: B1: If nuclide m decays directly, calculate the concentration of nuclide m in the control loop. The formula is as follows: (9) In formula (9): denoted as the initial concentration of nuclide m in the control volume loop. This is the quantity for the first intermediate process; First intermediate process quantity The calculation formula is as follows: (10) In formula (10): For circulation filtration efficiency, Let m be the decay constant of nuclide m. For circulation flow rate, For export flow rate, To control the volume; B2: If nuclide m is derived from the decay of nuclide m-1 or nuclide m-2, where nuclide m-1 is the parent nuclide of nuclide m and nuclide m-2 is the parent nuclide of nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows: （11） In formula (11), For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. Let mk be the decay constant of the nuclide mk. This represents the initial concentration of nuclide mk in the control volume loop. This is the quantity for the third intermediate process, where k takes the value 1 or 2; The formula for calculating the quantity of the third intermediate process is as follows: （13） in: (14) In formula (14): The cyclic filtration efficiency of mk nuclides. Let be the decay constant of nuclide mk, where k takes the value 1 or 2; B3: If nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m, then calculate the concentration of nuclide m in the control volume loop. The formula is as follows: (15) In formula (15): The proportion of nuclide m-2 entering the control volume from the inlet medium. This represents the initial concentration of nuclide m-2 in the control volume loop. and According to formula (13).

2. The method for calculating the radioactive source term of the control body according to claim 1, characterized in that, When the control unit is a containment ventilation system, the circulation filtration efficiency is obtained based on the type of radioactive gas and the parameters of the containment. , control the inlet flow rate Outlet flow velocity F, circulating flow velocity m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes: (16) In formula (16): When the radioactive gas is an inert gas, the circulation filtration efficiency is... The efficiency is 0 when the radioactive gas is iodine; the circulating filtration efficiency is 0. The efficiency is 0.999 when the radioactive gas is an aerosol, representing the circulating filtration efficiency. It is 0.99; （17） In formula (17): Inlet flow rate at the control body inlet The inflow velocity D1 is the containment flow rate, the outlet velocity F is the containment outflow velocity D2, and the circulation velocity is... The circulating flow rate D3 within the containment structure; (18) In formula (18): m-nucleoside deposition fraction =1; (19) In formula (19): When the radioactive gas is an inert gas, the proportion of nuclide m entering the control body from the inlet medium. for When the radioactive gas is iodine, the proportion of nuclide m entering the control medium from the inlet medium... for When the radioactive gas is an aerosol, the proportion of m nuclide entering the control medium from the inlet medium. for ,in, , and All of them are volatile factors.

3. The method for calculating the radioactive source term of the control body according to claim 1, characterized in that, When the control body is a water tank ventilation system, the inlet flow rate at the control body inlet is obtained based on the type of radioactive gas and the parameters of the containment vessel. Outlet flow velocity F, circulating flow velocity m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes: (20) In formula (20): Inlet flow rate at the control body inlet The inflow rate D1, outlet velocity F, and circulation velocity of the water tank are given. All are zero; (21) In formula (21): When the radioactive gas is an inert gas, the m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. All When the radioactive gas is iodine, the m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. All When the radioactive gas is an aerosol, the deposition fraction of m nuclides The proportion of m-nuclides entering the control body from the inlet medium. All ,in , and All of these are sedimentation factors.

4. The method for calculating the radioactive source term of the control body according to claim 1, characterized in that, When the control body is a factory ventilation system, the inlet velocity at the control body inlet is obtained according to the type of radioactive gas and the parameters of the factory ventilation system. Outlet flow velocity F, circulating flow velocity m-nuclide deposition fraction The proportion of m-nuclides entering the control body from the inlet medium. Specifically, it includes: （22） In formula (22): Inlet flow rate at the control body inlet The inflow rate D1, outlet velocity F, and circulating velocity of the factory ventilation system are given. All are zero; （23） In formula (23): m-nucleoside deposition fraction =1; (24) In formula (24): When the radioactive gas is an inert gas, the proportion of nuclide m entering the control body from the inlet medium. for When the radioactive gas is iodine, the proportion of nuclide m entering the control body from the inlet medium... for When the radioactive gas is an aerosol, the proportion of m nuclide entering the control body from the inlet medium. All ,in, , and All of them are volatile factors.

5. A device for calculating the radioactive source term of a control body, characterized in that, The device is used to calculate the radioactive source term of a control body. The control body includes an inner circulation structure and an outer circulation structure. The inner circulation structure forms an inner circulation within the control body, and the outer circulation structure includes a control body inlet and a control body outlet. The control body inlet and outlet form an outer circulation outside the control body. The state of the inner circulation within the control body includes an inner circulation running state and an inner circulation closed state. The state of the outer circulation outside the control body includes an outer circulation running state and an outer circulation closed state. The device includes a first computing unit and a second computing unit connected in parallel. The first calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the external circulation and the internal circulation of the control body when the control body is in the state of external circulation operation and internal circulation operation. The second calculation unit is used to calculate the concentration of the nuclide in the control body loop based on the operating parameters of the control body during the internal loop operation when the external loop is closed and the internal loop is running. The first computing unit includes a first computing module, a second computing module, and a third computing module connected in parallel. The first calculation module is used to calculate the concentration of nuclide m in the control body loop when nuclide m enters the container directly into the control body. , Calculate the concentration of nuclide m in the control volume loop. The formula is as follows: (25) In formula (25): To control the inlet flow velocity at the body inlet, The activity concentration of the upstream nuclide of nuclide m. The proportion of m-nuctoplasm entering the control medium from the inlet medium. The first intermediate process quantity is t, where t is the time it takes to enter the container of the control body. First intermediate process quantity The calculation formula is as follows: (26) In formula (26): For circulation filtration efficiency, For circulation flow rate, For export flow rate, To control the volume, Let m be the decay constant of nuclide m. The second calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is derived from the decay of nuclide m-1 or nuclide m-2. , Nuclide m-1 is the parent nuclide of nuclide m, nuclide m-2 is the parent nuclide of nuclide m, and the concentration of nuclide m in the control volume loop. The calculation formula is as follows: (27) In formula (27), For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. This is the quantity for the second intermediate process. This is the quantity for the third intermediate process, where k takes the value 1 or 2; The formulas for calculating the quantities of the second and third intermediate processes are as follows: (28) （29） (30) The cyclic filtration efficiency of mk nuclides. Let mk be the decay constant of the nuclide mk; The third calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m. , Concentration of nuclide m in the control loop The formula is as follows: （31） In formula (31) This is the fourth intermediate process quantity, and the formula for calculating the fourth intermediate process quantity is as follows: （32） In this context, k takes the value 1 or 2; The second computing unit includes a fourth computing module, a fifth computing module, and a sixth computing module connected in parallel. The fourth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m decays directly. The concentration of nuclide m in the control loop The calculation formula is as follows: (33) In formula (33): denoted as the initial concentration of nuclide m in the control volume loop. This is the quantity for the first intermediate process; First intermediate process quantity The calculation formula is as follows: (34) In formula (34): For circulation filtration efficiency, Let m be the decay constant of nuclide m. For circulation flow rate, For export flow rate, To control the volume; The fifth calculation module is used to calculate the concentration of nuclide m in the control volume loop, since nuclide m-1 is the parent nuclide of nuclide m-1 and nuclide m-2 are the parent nuclide of nuclide m-2. , Concentration of nuclide m in the control loop The formula is as follows: （35） In formula (35), For m-nuclide deposition fraction, The proportion of mk parent nucleus decaying into m nuclide. Let mk be the decay constant of the nuclide mk. This represents the initial concentration of nuclide mk in the control volume loop. This is the quantity for the third intermediate process, where k takes the value 1 or 2; The formula for calculating the quantity of the third intermediate process is as follows: （37） in: (38) In formula (38): The cyclic filtration efficiency of mk nuclides. Let be the decay constant of nuclide mk, where k takes the value 1 or 2; The sixth calculation module is used to calculate the concentration of nuclide m in the control volume loop when nuclide m is obtained by first decaying nuclide m-2 into nuclide m-1, and then into nuclide m. , Concentration of nuclide m in the control loop The calculation formula is as follows: (39) In formula (39): The proportion of nuclide m-2 entering the control medium from the inlet medium. This represents the initial concentration of nuclide m-2 in the control volume loop. and According to formula (37).

6. A method for evaluating the radioactive source term of a control body, characterized in that, Including the following steps: Using the radioactive source term calculation method of the control body as described in any one of claims 1-4, the active concentration of radionuclides transported, accumulated, and emitted in each process loop is obtained. Determine whether the active concentration is less than a preset threshold, and determine the radiation impact based on the determination result: if the determination result is yes, determine that the active concentration meets the radiation requirements; If the result is negative, it is determined that the active concentration does not meet the radiation requirements.

Images