CN112000922B

CN112000922B - Special nuclide radiation environment influence evaluation system for post-treatment plant

Info

Publication number: CN112000922B
Application number: CN202010662389.1A
Authority: CN
Inventors: 杨洁; 廉冰; 王彦; 赵杨军; 王猛; 康晶; 罗恺
Original assignee: China Institute for Radiation Protection
Current assignee: China Institute for Radiation Protection
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2023-08-29
Anticipated expiration: 2040-07-10
Also published as: CN112000922A

Abstract

The invention discloses a system for evaluating the influence of special nuclide radiation environment in a post-treatment plant, which comprises the following components: the special nuclide basic information module is used for storing basic information of each special nuclide; the field characteristic data module is used for storing field basic information; the nuclide release source item module is used for storing release parameters and pollutant parameters; the atmosphere diffusion module is used for modulating parameters of the site characteristic data module and the nuclide release source item module, and outputting an atmosphere diffusion factor and the nuclide ambient air concentration after calculation by corresponding calculation formulas; the environment medium special nuclide concentration calculation module is used for calling parameters of the atmosphere diffusion module and the nuclide release source item module, embedding evaluation parameters and calculating the concentration of special nuclides in soil, plant products and animal products; and the nuclide dose evaluation result output module is used for calculating the public dose caused by each special nuclide. The invention can realize the public radiation dose evaluation of the emission of key pollutants of the post-treatment plant.

Description

Special nuclide radiation environment influence evaluation system for post-treatment plant

Technical Field

The invention relates to the field of radiation environment influence evaluation, in particular to a system for evaluating the radiation environment influence of special nuclides in a post-treatment plant.

Background

The main process of nuclear fuel post-treatment is a PUREX flow, and radioactive waste gas can be generated in the processes of shearing, dissolving, waste liquid evaporating, treating and the like of waste fuel. The national atom radiation effect committee statistics show that: post-treatment plant air load in 1998-2002 ³ H release amount is 2001TBq, liquidState of ³ The H release amount is 84473TBq; airborne vehicle ¹⁴ C release amount was 44.16TBq, liquid state ¹⁴ The release amount of C is 105.5TBq; airborne vehicle ⁸⁵ Kr release amount was 2.16X10 ⁶ TBq; airborne vehicle ¹²⁹ I release amount was 0.14TBq, liquid state ¹²⁹ The amount of I released was 12.18TBq. It can be seen that T, T in the post-treatment process, ¹⁴ C、 ⁸⁵ Kr and ¹²⁹ the I species are contributors to primary emissions.

T、 ¹⁴ C is the most ubiquitous element in living cells compared to other nuclides, which is prone to enrichment and exchange in organisms, taking into account the public doses caused by the different chemical forms of T, such as inorganic tritium HTO and organic tritium OBT. ¹²⁹ I has a long half-life of 1570 ten thousand years, and its entry into the human body is selectively enriched in the thyroid gland, thus ¹²⁹ I is the focus of internal irradiation of the thyroid gland. ⁸⁵ Kr belongs to a radioactive inert gas nuclide which rapidly diffuses in the atmosphere, cannot be absorbed by the human body, and mainly produces external irradiation to the human body. It can be seen that T, compared to other nuclides, ¹⁴ C、 ⁸⁵ Kr and ¹²⁹ the existence form and migration behavior of the I nuclide in the environment are different from other nuclides, so that a special nuclide T is required to be independently developed, ¹⁴ C、 ⁸⁵ Kr and ¹²⁹ i, research work of migration rules and evaluation methods.

And (3) establishing a special nuclide evaluation system to evaluate the dosage of the main contribution nuclides for evaluating the environmental impact of the post-treatment plant. The method is suitable for post-treatment plants and the like and involves the following four radionuclides T, ¹⁴ C、 ⁸⁵ Kr and ¹²⁹ i nuclear facilities for emission. At present, the post-treatment facilities in China are still in a preliminary research stage, and no special nuclide evaluation system is established. Differences in migration behavior of different specific nuclides, differences in nuclide properties, lead to differences in the assessment model and the critical illuminated pathways of personnel.

In order to solve the problem of effective evaluation of public radiation influence caused by nuclide release from effluent of a post-treatment plant in the future, the invention aims to establish a special nuclide radiation environment influence evaluation system of the post-treatment plant, determine main radiation dose sources of nuclides through migration behavior research of special nuclides and identification of key paths, acquire evaluation modes of different nuclides and establish the evaluation system of the special nuclides of the post-treatment plant.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a special nuclide radiation environment influence evaluation system for a post-treatment plant, which can realize the public radiation dose evaluation of the emission of key pollutants of the post-treatment plant.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

an aftertreatment plant specific nuclide radiation environmental impact evaluation system comprising:

the special nuclide basic information module is used for storing basic information of each special nuclide, wherein the basic information comprises half-life period, decay constant and dose conversion factor of each special nuclide; the method is also used for screening the key irradiation paths of the public caused by each special nuclide according to the property of each special nuclide;

the site characteristic data module is used for storing site basic information, wherein the site basic information comprises plant site environment parameters and population recipe parameters;

the nuclide release source item module is used for storing release parameters and pollutant parameters;

the atmosphere diffusion module is used for calling the parameters of the site characteristic data module and the nuclide release source item module, outputting an atmosphere diffusion factor and the nuclide ambient air concentration after calculation by corresponding calculation formulas, and determining different calculation formulas according to the height of the emission source, the height of the adjacent highest building and the distance from the receiving point to the emission point;

the environment medium special nuclide concentration calculation module is used for calling parameters of the atmosphere diffusion module and the nuclide release source item module, embedding evaluation parameters and calculating the concentration of special nuclides in soil, plant products and animal products;

And the nuclide dose evaluation result output module is used for calling information parameters in the special nuclide basic information module, the site characteristic data module, the nuclide release source item module, the atmosphere diffusion module and the environment medium special nuclide concentration calculation module, and calculating the public dose caused by each special nuclide based on the key irradiation path of the public caused by each screened special nuclide.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant, as described above, wherein the special nuclide basic information module, the field characteristic data module, the nuclide release source item module, the atmospheric diffusion module, the environment medium special nuclide concentration calculation module and the nuclide dosage evaluation result output module are further configured to: various data stored by the device is managed, including input, modification, export and inquiry, and related data is output according to radiation environment influence evaluation requirements.

Further, a post-treatment plant specific nuclide radiation environmental impact assessment system as described above, the plant site environmental parameters including average wind speed and stability at release altitude, the population recipe parameters including plant site assessment range demographics and site recipe data including yield of food in the plant site area, intake of different types of food, and intake share of the assessment area;

The release parameters include a release stack number, stack height, exhaust rate, adjacent building height, and the pollution source parameters include nuclide name and annual release.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the atmospheric diffusion module is specifically used for:

1) If the height H of the discharge source is greater than 2.5 times the height H of the adjacent highest building _b I.e. H > 2.5H _b The atmospheric diffusion factor is calculated by the following formula:

C _air，i (x) The method comprises the following steps The concentration of the nuclide i in air, bq/m, at the release point x ³ The method comprises the steps of carrying out a first treatment on the surface of the i is nuclide T, ¹⁴ C、 ⁸⁵ Kr or ¹²⁹ I；

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

P _p : the time share of the fan-shaped azimuth p where the wind blows to the receiving point in one year is 0.25;

f: gaussian diffusion factor of release height, i.e. discharge source height H, at lee distance release point x, 1/m ² ；

u _a : average annual wind speed at release altitude, m/s;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

x: releasing the distance from the point to the calculated point, m;

u in equation (1) is calculated by the following equation _a ：

u ₁₀ : wind speed at a height of 10m from the ground, m/s;

h: discharge source height, m;

n: wind profile coefficients;

F in formula (1) is calculated by the following formula:

x: releasing the distance from the point to the calculated point, m;

σ _z : vertical diffusion parameter, m;

if H is less than or equal to 45m, in the formula (3)

2) If the height H of the discharge source is less than or equal to 2.5H _b And (2) andthe atmospheric diffusion factor is calculated by the following formula:

C _air，i (x) The method comprises the following steps The concentration of the nuclide i in air, bq/m, at the release point x ³ The method comprises the steps of carrying out a first treatment on the surface of the I is a nuclide T, 14C, 85Kr, or 129I;

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

b: gaussian diffusion factor at lee distance x, 1/m ² ；

u _a : average annual wind speed at release altitude, m/s;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: releasing the distance from the point to the calculated point, m;

b in formula (4) is calculated by the following formula:

σ _z : vertical diffusion parameter, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: releasing the distance from the point to the calculated point, m;

3) If the height H of the discharge source is less than or equal to 2.5H _b And (2) andand the receiving point is not on the surface of the building where the releasing point is located, the atmospheric diffusion factor is calculated by the following formula:

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

u _a : average annual wind speed at release altitude, m/s;

k: experience constant, 1m;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: the distance from the release point to the calculation point, m.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the module for calculating the concentration of the special nuclide in the environment medium is specifically used for: calculating the HTO concentration in soil, the HTO concentration in plant products, the HTO concentration in drinking water and forage water, the HTO concentration in terrestrial animal and plant products, the OBT concentration in terrestrial products and the OBT concentration in animal products;

1) HTO concentration in soil is calculated by the formula:

C _sw，HTO (x) The method comprises the following steps The concentration of HTO in the soil water, bq/L, at a distance x from the release point;

CR _s-a : an empirical constant;

C _air，HTO (x) The method comprises the following steps The concentration of HTO in air, bq/m, at a distance x from the release point ³ ；

H _a : absolute humidity, L/m ³ ；

x: releasing the distance from the point to the calculated point, m;

2) HTO concentration in the plant product is calculated by the formula:

C _f，HTO (x) The method comprises the following steps The concentration of HTO in the plant product, fresh weight, bq/kg, at the release point x;

WC _P : the water content, fresh weight and L/kg of plants;

RH: relative humidity;

H _a : absolute humidity, L/m ³ ；

gamma: the ratio of HTO saturated vapor pressure in water;

x: releasing the distance from the point to the calculated point, m;

3) HTO concentrations in drinking water and forage water were calculated by the following formula:

CR _f，HTO (x) The method comprises the following steps The HTO concentration in the drinking water/forage water (assuming 50% intake from drinking water, 50% from forage), bq/L;

C _sw，HTO (x) The method comprises the following steps Release at a distanceThe concentration of HTO in soil water at the placing point x, bq/L;

C _{pasture，HTO} (x) The method comprises the following steps Concentration of HTO in soil water, bq/kg, at a distance x from the release point;

WC _P : the water content (fresh weight) of the plants, L/kg;

x: releasing the distance from the point to the calculated point, m;

4) HTO concentration in terrestrial animal and plant products is calculated by the formula:

C _f，HTO (x)＝CR _a，HTO ·CR _f，HTO (x) (11)

C _f，HTO (x) The method comprises the following steps HTO concentration, bq/kg in terrestrial animal and plant products;

CR _a，HTO (x) The method comprises the following steps The proportion of the activity concentration of the ingested HTO in the water tritium absorption is L/kg;

x: releasing the distance from the point to the calculated point, m;

5) The concentration of OBT in terrestrial products was calculated by the following formula:

C _f，OBT (x) The method comprises the following steps Concentration of OBT, bq/kg in animal products;

WC _P : the water content (fresh weight) of the plants, L/kg;

WEQ _P : water equivalent factor, L/kg;

R _p : branching factors;

C _f，HTO (x) The method comprises the following steps The concentration of HTO, bq/kg in the plant product;

x: releasing the distance from the point to the calculated point, m;

6) The concentration of OBT in the animal product is calculated by the formula:

C _f，OBT (x)＝CR _a，OBT ·C _{pasture，OBT} (x) (13)

CR _a，OBT (x) The method comprises the following steps The activity concentration of the ingested OBT is on feedThe ratio of the tritium to L/kg;

C _{pasture，OBT} (x) The method comprises the following steps Average concentration of OBT in feed, bq/kg;

x: the distance from the release point to the calculation point, m.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the module for calculating the concentration of the special nuclide in the environment medium is specifically used for: calculating plant products ¹⁴ C concentration and polluted river irrigation plant product ¹⁴ C concentration and animal products ¹⁴ C concentration;

1) Plant product ¹⁴ C concentration, calculated by the formula:

C _air，14C (x) The method comprises the following steps C-14 concentration at the release point x, bq/m3;

S _p : the concentration of stable carbon in the plant product, g C/kg fresh weight;

S _air : concentration of stable carbon in air g C/m ³ ；

SA _air : plant product specific activity Bq/g C;

x: releasing the distance from the point to the calculated point, m;

2) Plant product for irrigation of polluted river water ¹⁴ C concentration, calculated by the formula:

SA _air : plant product specific activity Bq/g C;

CD _s : dilution factor, value 0.15;

I _irr : irrigation rate of 0.005m ³ /m ² ；

C _uw，s : concentration of nuclide activity in water, bq/m ³ ；

Fc: plant product residuesRate of decomposition to carbon, 0.66 (g C)/m ² ；

x: releasing the distance from the point to the calculated point, m;

3) Animal products ¹⁴ C concentration, calculated by the formula:

f _C ： ¹⁴ c, the feeding share of the plant is 1 by default;

C _{pasture，14C} (x) The method comprises the following steps The concentration of C-14 in the forage at the release point x;

S _a : the concentration of stable carbon in animal products, fresh weight, g C/kg;

S _p : the concentration of stable carbon in the forage, the fresh weight, g C/kg;

x: the distance from the release point to the calculation point, m.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the module for calculating the concentration of the special nuclide in the environment medium is specifically used for: nuclides in computing environment media ¹²⁹ The concentration of I is calculated by the formula:

C _f，i (x)＝C _f，unit，i ·d _i (x) (17)

d _i (x)＝V _T C _air，i (x) (18)

C _f，unit，i : concentration of nuclide i in plants, bq/kg/Bq (m ² s) or Bq/L/Bq (m) ² s); i is a nuclide ¹²⁹ I；

d _i (x) The method comprises the following steps Annual average deposition rates of nuclide i, including dry and wet deposition, bq s/m ² ；

V _T : dry and wet deposition rates, m/s, ¹²⁹ i, taking 0.002;

C _air，i (x) The method comprises the following steps The concentration of the nuclide i in air, bq/m, at the release point x ³ ；

x: the distance from the release point to the calculation point, m.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the nuclide dose evaluation result output module is specifically configured to: calculating the public doses caused by nuclide T, wherein the public doses caused by tritium comprise inhalation doses and ingestion doses, and the public doses are calculated by the following formula:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ing)，f，r，i} (x) (19)

1) Inhalation dose, calculated by the formula:

H _E(inh)，i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide T;

C _air，i (x) The method comprises the steps of carrying out a first treatment on the surface of the The concentration of the nuclide i in air, bq/m, at the release point x ³ ；

D _inh，i : inhalation dose-converting factor of nuclide i, sv/Bq, H-3, 4.5X10 ^-11 ；

I _inh : respiration rate, m ³ D, taking 20;

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (20) is calculated by the following formula _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance from the point to the calculated point, km;

n: experience factor, T, takes 1.2;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

2) The intake dose is calculated by the following formula:

H _{E(ing)，f，r，i} (x)＝C _f，i (x)·D _ing，i ·F _local ·I _f，r (22)

H _{E(ing)，f，r，i} (x) The method comprises the following steps The feeding dose of nuclide i, sv;

C _f，i (x) The method comprises the following steps The concentration of nuclide i in the product, bq/kg or Bq/L;

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : the yield of food in the area, kg or L.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the nuclide dose evaluation result output module is specifically configured to: calculating nuclides ¹⁴ The public dose caused by C is given by the formula, ¹⁴ the public dose caused by C comprises inhalation dose, air immersion external irradiation dose and eating dose, and is calculated by the following formula:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ing)，f，r，i} (x) (23)

1) Inhalation dose, calculated by the formula:

H _E(inh)，i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide ¹⁴ C；

D _inh，i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ D, taking 20 by adults;

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (24) is calculated by _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹⁴ c, taking 1.4;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

2) The air immersion external irradiation dose is calculated by the following formula:

H _{E(ex，cloud)，i} (x)＝C _air，i (x)·D _{ex，cloud，i} ·O _ann ·(O _out +(1-O _out )·L _cloud ) (26)

H _{E(ex，cloud)，i} (x) The method comprises the following steps The dose caused by the smoke plume immersion of the nuclide i at a distance x from the release point, sv/a;

O _ann : annual residence time, s/a;

D _{ex，cloud，i} : smoke plume immersion dose conversion factor, sv/(Bq s/m) ³ )；

O _out : outdoor shareTaking 0.2;

L ^c _loud : taking 0.2 of shielding factor of the building;

C _air，i (x) The method comprises the following steps The activity concentration, bq/m, of the nuclide i in air at a distance x from the release point ³ ；

3) The intake dose is calculated by the following formula:

H _{E(ing)，f，r，i} (x)＝C _f，i (x)·D _ing，i ·F _local ·I _f，r (27)

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : the yield of food in the area, kg or L.

Further, the system for evaluating the influence of the radiation environment of the special nuclide in the post-treatment plant is as described above, and the nuclide dose evaluation result output module is specifically configured to: calculating nuclides ¹²⁹ The public dose caused by the factor I, ¹²⁹ the public dose caused by I comprises inhalation dose, air immersion external irradiation dose, surface deposition external irradiation dose and feeding dose, and is calculated by the following formula:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ex，cloud)} ，i(x)+H _{E(ex，deposit)，i} (x)+H _{E(ing)，f，r，i} (x) (28)

1) Inhalation dose, calculated by the formula:

H _E(inh)，i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide ¹²⁹ I；

C _air，i (x) The method comprises the steps of carrying out a first treatment on the surface of the Release at a distanceThe concentration of nuclide i in air, bq/m, at the discharge point x ³ ；

D _inh，i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ /d；

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ^7w；

x: releasing the distance from the point to the calculated point, m;

c in the formula (29) is calculated by _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹²⁹ i, 1.42;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

H _{E(ex，cloud)，i} (x)＝C _air，i (x)·D _{ex，cloud，i} ·O _ann ·(O _out +(1-O _out )·L _cloud ) (31)

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

3) The surface deposition external irradiation dose is calculated by the following formula:

H _{E(ex，deposit)，i} (x)＝d _i (x)·t _discharge ·D _{ex，deposit，i} ·(O _out +(1-O _out )·L _deposit ) (32)

H _{E(ex，deposit)，i} (x) The method comprises the following steps Dose, sv, caused by external irradiation of surface deposition of nuclide i;

t _discharge : deposition time, 3.15X10 ⁷ s；

D _{ex，deposit，i} : dose-conversion factor of nuclide i, sv/(Bq/m) ² )；

O _out : taking an outdoor share of 0.2;

L _deposit : building shielding factors, taking 0.1;

4) The intake dose is calculated by the following formula:

H _{E(ing)，f，r，i} (x)＝C _f，i (x)·D _ing，i ·F _local ·I _f，r (33)

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : yield of food in the area, kg or L;

the nuclide dose evaluationThe price result output module is specifically used for: calculating nuclides ⁸⁵ The public dose caused by Kr, ⁸⁵ the public radiation path caused by Kr is air immersed external radiation, and is calculated by the following formula:

H _{E(ex，cloud)，i} (x)＝C _air，i (x)·D _{ex，cloud，i} ·O _ann ·(O _out +(1-O _out )·L _cloud ) (34)

H _{E(ex，cloud)，i} (x) The method comprises the following steps The dose caused by the smoke plume immersion of the nuclide i at a distance x from the release point, sv/a; i is a nuclide ⁸⁵ Kr；

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

x: the distance from the release point to the calculation point, m.

The invention has the beneficial effects that: according to the invention, through the special nuclide basic information module, the site characteristic data module, the nuclide release source item module, the atmospheric diffusion module, the environment medium special nuclide concentration calculation module and the nuclide dosage evaluation result output module, the atmospheric concentration in the environment air of the special nuclide airborne effluent and the effective dosage of the public year caused by the atmospheric concentration in the environment air are calculated under the normal working condition, and the public radiation dosage evaluation of the key pollutant emission of the post-treatment plant is realized.

Drawings

FIG. 1 is a schematic diagram of a system for evaluating the influence of a specific nuclide radiation environment in a post-treatment plant according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the key irradiation paths of public doses caused by specific nuclides provided in an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the drawings and the detailed description.

In order to solve the problem of effective evaluation of public radiation influence caused by nuclide release from effluent of a post-treatment plant in the future, the invention needs to establish a special nuclide radiation environment influence evaluation system of the post-treatment plant, determine main radiation dose sources of nuclides through migration behavior research of special nuclides and identification of key paths, acquire evaluation modes of different nuclides and establish the special nuclide evaluation system of the post-treatment plant.

As shown in fig. 1, an after-treatment plant special nuclide radiation environmental impact evaluation system includes: the system comprises a special nuclide basic information module, a field characteristic data module, a nuclide release source item module, an atmosphere diffusion module, an environment medium special nuclide concentration calculation module and a nuclide dosage evaluation result output module. The module is also used for data storage management, comprising data input, modification, export and inquiry functions, and outputting related data according to radiation environment influence evaluation requirements. The main function of the system is to calculate the atmospheric concentration in the air of the special nuclide airborne effluent under the normal working condition and the effective dose of the special nuclide airborne effluent in public years.

(1) Special nuclide basic information module

The special nuclide basic information module mainly comprises nuclide T, ¹⁴ C、 ⁸⁵ Kr and ¹²⁹ basic information of I, half-life (T _1/2 ) Decay constant (λ), dose conversion factor.

The key irradiation path of the public caused by the special nuclide is screened according to the property of the special nuclide. Wherein the tritium-induced public doses include inhaled doses and ingested doses. ¹⁴ The public dose caused by C comprises inhalation dose, air immersion external irradiation dose and eating dose. ¹²⁹ The public doses caused by I include inhalation doses, air immersion external irradiation doses, surface deposition external irradiation doses and eating doses. ⁸⁵ The public radiation pathway caused by Kr is air-immersed external radiation. Setting an inhalation dose rate conversion factor (DF) in a module _inh ) Conversion factor of air immersion external irradiation (DF) _clo ) Surface deposition external irradiation conversion factor (DF) _dep ) Food intake dose conversion factor (DF) _ing ) Is provided. The settings of the parameters are shown in Table 1.

TABLE 1 basic information parameters of specific nuclides

(2) Address feature data module

The site characteristic data module refers to site basic information and mainly comprises plant site environment parameters and population recipe parameters. The plant site environmental parameters include average wind speed at release altitude, stability. Stability may be obtained from weather station data in the vicinity of the facility. The population recipe parameters include site-wide population distribution and site recipe data. The site recipe data includes the yield of food (meat, milk, eggs, vegetables, grains, etc.), the intake of different kinds of food (meat, milk, eggs, vegetables, grains, etc.) and the intake share of the evaluation area in the site area.

(3) Nuclide release source item module

The nuclide release source term module mainly comprises release parameters and pollutant parameters. The release parameters include release stack number, stack height, exhaust rate, and adjacent building height. Pollution source parameters include nuclide name and annual release.

(4) Atmospheric diffusion module

The atmospheric diffusion module uses a dilution mode calculation. And calling basic parameters from the site characteristic data module and the nuclide release source term module, and outputting diffusion factors and nuclide ambient air concentration after calculation by corresponding formulas.

The atmosphere dispersion mode adopts a dilution mode, and takes the dilution effect of the atmosphere into consideration, and does not take the lifting of smoke plumes into consideration. And according to the height of the emission source, the height of the adjacent highest building and the distance between the receiving point and the emission point, determining a calculation formula adopting different forms.

1) If the height of the discharge source, i.e. the release height H, is greater than 2.5 times the height H of the adjacent highest building _b I.e. H > 2.5H _b The atmospheric diffusion factor is calculated by the following formula:

Q _i : nuclide release rate, bq/s;

D _i : atmospheric diffusion factor, s/m ³ ；

f: gaussian diffusion factor of release height (H) at a distance x km from the release point down wind, 1/m ² ；

u _a : the annual average wind speed at release altitude, m/s. The method comprises the steps of carrying out a first treatment on the surface of the

H: discharge source height, m;

H _b : adjacent the height of the highest building, m.

U in equation (1) is calculated by the following equation _a ：

u ₁₀ : wind speed at a height of 10m from the ground, m/s;

h: discharge source height, m;

n: wind profile coefficient.

The values of the wind profile coefficients n are shown in Table 2 below.

TABLE 2 wind profile coefficient

F in formula (1) is calculated by the following formula:

x: releasing the distance from the point to the calculated point, m;

σ _z : vertical diffusion parameter, m.

If H is less than or equal to 45m, in the formula (3)

2) If the release height H is less than or equal to 2.5H _b And (2) andthe atmospheric diffusion factor is calculated by the following formula: />

Q _i : nuclide release rate, bq/s;

D _i : atmospheric diffusion factor, s/m ³ ；

b: gaussian diffusion factor at lee distance x, 1/m ² ；

u _a : average annual wind speed at release altitude, m/s;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² 。

B in formula (4) is calculated by the following formula:

σ _z : vertical diffusion parameter, m;

A _b : cross-sectional area adjacent to the highest building, m ² 。

3) If the release height H is less than or equal to 2.5H _b And (2) andand the receiving point is not on the surface of the building where the releasing point is located, the atmospheric diffusion factor is calculated by the following formula:

Q _i : nuclide release rate, bq/s;

D _i : atmospheric diffusion factor, s/m ³ ；

u _a : average annual wind speed at release altitude, m/s;

k: experience constant, 1m;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² 。

(5) Environment medium special nuclide concentration calculation module

The environmental medium special nuclide concentration calculation module is obviously different from the evaluation system of other nuclides. The module can call parameters of an atmospheric diffusion module and a nuclide release source module, embeds evaluation parameters, and calculates the concentration of special nuclides of soil, plant products and animal products. The module is internally provided with evaluation parameters.

1. Nuclide T

The method specifically comprises the following steps: HTO concentration in soil, HTO concentration in plant products, HTO concentration in drinking water and forage water, HTO concentration in terrestrial animal and plant products, OBT concentration in Liu Shengchan (crops, vegetables, forage), and OBT concentration in animal products.

1) HTO concentration in soil is calculated by the formula:

CR _s-a : an empirical constant;

H _a : absolute humidity, L/m ³ 。

2) HTO concentration in the plant product is calculated by the formula:

WC _P : the water content (fresh weight) of the plants, L/kg;

RH: relative humidity;

H _a : absolute humidity, L/m ³ ；

gamma: ratio of HTO saturated vapor pressure in water.

WC _P : the water content (fresh weight) of the plants, L/kg.

C _f，HTO (x)＝CR _a，HTO ·CR _f，HTO (x) (11)

CR _a，HTO (x) The method comprises the following steps The ratio of the activity concentration of the ingested HTO to the water tritium absorption, L/kg.

5) The concentration of OBT in terrestrial products (crops, vegetables, forage) is calculated by the formula:

WC _P : the water content (fresh weight) of the plants, L/kg;

WEQ _P : water equivalent factor, L/kg;

R _p : branching factors;

C _f，HTO (x) The method comprises the following steps HTO concentration, bq/kg in plant products.

6) The concentration of OBT in the animal product is calculated by the formula:

C _f,OBT (x)＝CR _a,OBT ·C _pasture,OBT (x) (13)

CR _a，OBT (x) The method comprises the following steps The ratio of the activity concentration of ingested OBT to the tritium in the feed, L/kg;

C _{pasture，OBT} (x) The method comprises the following steps Average concentration of OBT in feed, bq/kg.

7) Related parameters

The relevant parameters for T are shown in table 3 below.

Parameters (parameters)	(symbol)	Value of	Unit (B)
				HTO：H ₂ Vapor pressure of O saturation	γ	0.909	/
Absolute humidity	H _a	6×10 ^-3	L/m ³
				Relative humidity of	RH	0.7	/
Empirical constant	CR _s-a	0.3	/
				Water content share in crops (fresh weight)	WC _p	0.12	L/kg
Moisture content of vegetables (fresh weight)	WC _p	0.92	L/kg
				Moisture content in forage (fresh weight)	WC _p	0.76	L/kg
HTO concentration due to milk intake	CR _a，HTO	0.87	Bq/kg fresh weight/Bq/L
				HTO concentration due to meat ingestion	CR _a，HTO	0.66	Bq/kg fresh weight/Bq/L
Crop water equivalent factor	WEQ _p	0.56	L/kg
				Vegetable water equivalent factor	WEQ _p	0.51	L/kg
Forage water equivalent factor	WEQ _p	0.56	L/kg
				Plant product branching factor	R _p	0.54	/
OBT concentration due to milk intake	CR _a，OBT	0.24	Bq/kg fresh weight/Bq/kg dry weight
				OBT concentration due to meat ingestion	CR _a，OBT	0.4	Bq/kg fresh weight/Bq/kg dry weight

Table 3T calculate the relevant parameters

2. Nuclide species ¹⁴ C

Assume that ¹⁴ The C concentration is the same as the stable C concentration in plants, air. For computing in terrestrial products ¹⁴ Concentration of C, C _f，C-14 (x) Plant product at a distance x from the release point ¹⁴ C concentration and polluted river irrigation plant product ¹⁴ C concentration and animal products ¹⁴ The concentration of C is calculated as follows。

1) Plant product ¹⁴ C concentration, calculated by the formula:

S _air : concentration of stable carbon in air g C/m ³ ；

SA _air : plant product specific activity Bq/g C.

SA _air : plant product specific activity Bq/g C;

CD _s : dilution factor, value 0.15;

I _irr : irrigation rate of 0.005m ³ /m ² ；

C _uw，s : concentration of nuclide activity in water, bq/m ³ ；

F _c : the rate of carbon production by decomposition of plant product residues was 0.66 (g C)/m ² 。

3) Animal products ¹⁴ C concentration, calculated by the formula:

f _C ： ¹⁴ c, the feeding share of the plant is 1 by default;

C _{pasture，14C} (x) The method comprises the following steps The concentration of C-14 in the forage at distance x;

S _a : dynamic movementThe concentration of stable carbon in the product is g C/kg fresh weight;

S _p : the concentration of stable carbon in the forage was g C/kg fresh weight.

4) Related parameters

¹⁴ The relevant parameters for C are shown in table 4 below.

TABLE 4 Table 4 ¹⁴ C calculating related parameters

3. Nuclide species ¹²⁹ I

1) Nuclides in ambient medium ¹²⁹ The concentration of I is calculated by the formula:

C _f，i (x)＝C _f，unit，i ·d _i (x) (17)

d _i (x)＝V _T C _air，i (x) (18)

C _f，unit，i : radionuclide concentration in plants (100 years deposition considerations), bq/kg/Bq (m ² s) or Bq/L/Bq (m) ² s)；

d _i (x) The method comprises the following steps Annual average deposition rate, including dry and wet deposition, bq s/m ² ；

V _T : dry and wet deposition rates, m/s, I-129, taken at 0.002;

C _air，i (x) The method comprises the following steps Concentration of nuclide i in air, bq/m ³ 。

2) Related parameters

¹²⁹ Relevant parameters for I are shown in table 5 below.

Parameters (parameters)	(symbol)	Value of	Unit (B)
				In cereals ¹²⁹ I concentration	C _f，unit，i	6.00E+05	Bq/kg/Bq(m ² s)
In plants and fruits ¹²⁹ I concentration	C _f，unit，i	2.30E+05	Bq/kg/Bq(m ² s)
				In milk ¹²⁹ I concentration	C _f，unit，i	3.10E+05	Bq/L/Bq(m ² s)
In meat ¹²⁹ I concentration	C _f，unit，i	2.10E+05	Bq/kg/Bq(m ² s)
				Deposition rate	V _T	0.002	m/s

TABLE 5 ¹²⁹ I calculating relevant parameters

(6) Nuclide dose evaluation result output module

The nuclide dose evaluation result output module is used for outputting the normal working condition suction internal irradiation dose, the air immersion external irradiation dose, the surface deposition external irradiation dose and the feeding internal irradiation dose of each nuclide. Each nuclide includes: nuclide T, nuclide ¹⁴ C. Nuclide species ¹²⁹ I. Nuclide species ⁸⁵ Kr. In particular, tritium-induced public doses include inhaled and ingested doses. ¹⁴ The public dose caused by C comprises inhalation dose, air immersion external irradiation dose and eating dose. ¹²⁹ Public doses caused by I include inhalation doses, air immersion external radiation doses, surface deposition external radiation and ingestion doses. ⁸⁵ The public radiation pathway caused by Kr is air-immersed external radiation. As shown in fig. 2.

1. Nuclide T

Tritium-induced public doses include inhaled and ingested doses. The total dose formula is as follows:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ing)，f，r，i} (x) (19)

1) Inhalation dose, calculated by the formula:

I _inh : respiration rate, m ³ D, taking 20;

86400: conversion factor, s/d;

O _ann : time of residence of 3.15×10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (20) is calculated by the following formula _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance from the point to the calculated point, km;

n: experience factor, T, takes 1.2;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

2) The intake dose is calculated by the following formula:

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : the yield of food in the area, kg or L.

2. Nuclide species ¹⁴ C

Nuclide species ¹⁴ The public dose caused by C comprises inhalation dose, air immersion external irradiation dose and eating dose, and is calculated by the following formula:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ing)，f，r，i} (x) (23)

1) Inhalation dose, calculated by the formula:

D _inh，i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ D, taking 20 by adults;

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (24) is calculated by _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹⁴ c, taking 1.4;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

H _{E(ex，clouir，i} (x)＝C _air，i (x)·D _{ex，cloud，i} ·O _ann ·(O _out +(1-O _out )·L _cloud ) (26)

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

3) The intake dose is calculated by the following formula:

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : the yield of food in the area, kg or L.

3. Nuclide species ¹²⁹ I

Nuclide species ¹²⁹ The public dose caused by I comprises inhalation dose, air immersion external irradiation dose, surface deposition external irradiation dose and feeding dose, and is calculated by the following formula:

H _E(atoms)，i (x)＝H _E(inh)，i (x)+H _{E(ex，cloud)，i} (x)+H _{E(ex，deposit)，i} (x)+H _{E(ing)，f，r，i} (x) (28)

1) Inhalation dose, calculated by the formula:

D _inh，i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ /d；

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (29) is calculated by _air，i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹²⁹ i, 1.42;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

H _{E(ex，cloud)，i} (x)＝C _air，i (x)·D _{ex，cloud，i} ·C _ann ·(O _out +(1-O _out )·L _cloud ) (31)

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

3) Surface deposition external irradiation is calculated by the following formula:

H _{E(ex，deposit)，i} (x) The method comprises the following steps Surface deposition external irradiation of nuclide i, sv;

t _discharge : deposition time, 3.15X10 ⁷ s；

D _{ex，deposit，i} : dose-conversion factor of nuclide i, sv/(Bq/m) ² )；

O _out : taking an outdoor share of 0.2;

L _deposit : building shielding factors, taking 0.1;

4) The intake dose is calculated by the following formula:

H _{E(ing)，f，r，i} (x) The method comprises the following steps Feeding of nuclide iDose, sv;

D _ing，i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f，r : yield of food in the area, kg or L;

4. nuclide species ⁸⁵ Kr

Nuclide species ⁸⁵ The public radiation path caused by Kr is air immersed external radiation, and is calculated by the following formula:

H _{E(ex，cloud)} ， _i (x)＝C _air，i (x)·D _{ex，cloud，i} ·O _ann ·(O _out +(1-O _out )·L _cloud ) (34)

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

x: the distance from the release point to the calculation point, m.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A post-treatment plant specific nuclide radiation environmental impact evaluation system, comprising:

the nuclide dose evaluation result output module is used for calling information parameters in the special nuclide basic information module, the site characteristic data module, the nuclide release source item module, the atmosphere diffusion module and the environment medium special nuclide concentration calculation module, and calculating the public dose caused by each special nuclide based on the key irradiation path of the public caused by each screened special nuclide;

the specific steps of the atmospheric diffusion module for calculating and outputting the atmospheric diffusion factor are as follows: first, it is determined whether the height H of the discharge source is greater than 2.5 times the height H of the adjacent highest building _b If yes, calculating an atmospheric diffusion factor by using a preset formula I; if not, further judging whether the distance x from the release point to the calculation point is more than 2.5 times of the sectional area A of the adjacent highest building _b If yes, calculate large using the preset formula IIA gas diffusion factor; if not, calculating an atmospheric diffusion factor by using a preset formula III;

the environmental medium special nuclide concentration calculation module is particularly used for calculating the HTO concentration in soil, the HTO concentration in plant products, the HTO concentration in drinking water and forage water, the HTO concentration in terrestrial animal and plant products, the OBT concentration in terrestrial products, the OBT concentration in animal products and plant products ¹⁴ C concentration and polluted river irrigation plant product ¹⁴ C concentration and animal products ¹⁴ C concentration and nuclides in ambient medium ¹²⁹ Concentration of I;

the nuclide dose evaluation result output module is particularly used for calculating the public dose caused by nuclide T, wherein the public dose caused by tritium comprises inhalation dose and ingestion dose, and calculating nuclide ¹⁴ The public dose caused by C is given by the formula, ¹⁴ public doses caused by C include inhalation dose, air immersion external irradiation dose and feeding dose and nuclides ¹²⁹ Public doses caused by I.

2. The post-treatment plant special nuclide radiation environmental impact evaluation system according to claim 1, wherein the special nuclide basic information module, the site feature data module, the nuclide release source item module, the atmospheric diffusion module, the environmental medium special nuclide concentration calculation module, and the nuclide dose evaluation result output module are further configured to: various data stored by the device is managed, including input, modification, export and inquiry, and related data is output according to radiation environment influence evaluation requirements.

3. An after-treatment plant specific nuclide radiation environmental impact assessment system according to claim 1, wherein said site environmental parameters comprise mean wind speed and stability at release altitude, said population recipe parameters comprise site assessment range demographics and site recipe data comprising yield of site area foods, food intake of different kinds of foods and intake share of assessment area;

the release parameters include a release stack number, stack height, exhaust rate, adjacent building height, the pollutant parameters include nuclide name and annual release.

4. The system for evaluating the environmental impact of post-treatment plant specific nuclear radiation according to claim 1, wherein the atmospheric diffusion module calculates the atmospheric diffusion factor by specifically:

1) If the height H of the discharge source is greater than 2.5 times the height H of the adjacent highest building _b I.e. H>2.5H _b The atmospheric diffusion factor is calculated by the following preset formula one:

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

u _a : average annual wind speed at release altitude, m/s;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

x: releasing the distance from the point to the calculated point, m;

u in equation (1) is calculated by the following equation _a ：

u ₁₀ : wind speed at a height of 10m from the ground, m/s;

h: discharge source height, m;

n: wind profile coefficients;

f in formula (1) is calculated by the following formula:

x: releasing the distance from the point to the calculated point, m;

σ _z : vertical diffusion parameter, m;

if H is less than or equal to 45m, in the formula (3)

2) If the height H of the discharge source is less than or equal to 2.5H _b And (2) andthe atmospheric diffusion factor is calculated by the following preset formula two:

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

b: gaussian diffusion factor at lee distance x, 1/m ² ；

u _a : average annual wind speed at release altitude, m/s;

H: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: releasing the distance from the point to the calculated point, m;

b in formula (4) is calculated by the following formula:

σ _z : vertical diffusion parameter, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: releasing the distance from the point to the calculated point, m;

3) If the height H of the discharge source is less than or equal to 2.5H _b And (2) andand the receiving point is not positioned on the surface of the building where the releasing point is positioned, the atmospheric diffusion factor is calculated by the following preset formula III:

Q _i : the release rate of nuclide i, bq/s;

D _i : atmospheric diffusion factor of nuclide i, s/m ³ ；

u _a : average annual wind speed at release altitude, m/s;

k: experience constant, 1m;

h: discharge source height, m;

H _b : adjacent the height of the highest building, m;

A _b : cross-sectional area adjacent to the highest building, m ² ；

x: the distance from the release point to the calculation point, m.

5. The post-treatment plant specific nuclide radiation environmental impact evaluation system according to claim 1, wherein the environmental medium specific nuclide concentration calculation module specifically calculates by the following formula: the method comprises the steps of carrying out a first treatment on the surface of the

1) HTO concentration in soil is calculated by the formula:

CR _s-a : an empirical constant;

H _a : absolute humidity, L/m ³ ；

x: releasing the distance from the point to the calculated point, m;

2) HTO concentration in the plant product is calculated by the formula:

C _f，HTO (x) The method comprises the following steps The concentration of HTO in the plant product, fresh weight, bq/kg, at the release point x; WC (Wolfram carbide) _P : the water content, fresh weight and L/kg of plants;

RH: relative humidity;

H _a : absolute humidity, L/m ³ ；

gamma: the ratio of HTO saturated vapor pressure in water;

x: releasing the distance from the point to the calculated point, m;

CR _f，HTO (x) The method comprises the following steps HTO concentration in drinking water/forage water, bq/L;

WC _P : the water content, fresh weight and L/kg of the plants;

x: releasing the distance from the point to the calculated point, m;

C _f,HTO (x)＝CR _a,HTO ·CR _f,HTO (x) (11)

CR _a，HTO (x) The method comprises the following steps The proportion of the activity concentration of the ingested HTO in the water tritium absorption is L/kg; x: releasing the distance from the point to the calculated point, m;

C _f-p，OBT (x) The method comprises the following steps The concentration of OBT, bq/kg in the plant product;

WC _P : the water content, fresh weight and L/kg of plants;

WEQ _P : water equivalent factor, L/kg;

R _p : branching factors;

C _f-p，HTO (x) The method comprises the following steps The concentration of HTO, bq/kg in the plant product;

x: releasing the distance from the point to the calculated point, m;

6) The concentration of OBT in the animal product is calculated by the formula:

C _f-a,OBT (x)＝CR _a,OBT ·C _pasture,OBT (x) (13)

C _f-a，OBT (x) The method comprises the following steps Concentration of OBT, bq/kg in animal products;

x: the distance from the release point to the calculation point, m.

6. The system for evaluating the environmental impact of post-treatment plant specific nuclide radiation of claim 1, wherein said environmental medium specific nuclide concentration calculation module calculates the plant product by the following formula ¹⁴ C concentration and polluted river irrigation plant product ¹⁴ C concentration and animal products ¹⁴ C concentration;

1) Plant product ¹⁴ C concentration, calculated by the formula:

S _air : concentration of stable carbon in air g C/m ³ ；

SA _air : plant product specific activity Bq/g C;

x: releasing the distance from the point to the calculated point, m;

SA _air : plant product specific activity Bq/g C;

CD _s : dilution factor, value 0.15;

I _irr : irrigation rate of 0.005m ³ /m ² ；

C _uw，s : concentration of nuclide activity in water, bq/m ³ ；

F _c : the rate of carbon production by decomposition of plant product residues was 0.66 (g C)/m ² ；

x: releasing the distance from the point to the calculated point, m;

3) Animal products ¹⁴ C concentration, calculated by the formula:

f _C ： ¹⁴ c, the feeding share of the plant is 1 by default;

x: the distance from the release point to the calculation point, m.

7. A post-treatment plant specific nuclide according to claim 1The radiation environment influence evaluation system is characterized in that the environment medium special nuclide concentration calculation module calculates nuclides in the environment medium ¹²⁹ The concentration of I is calculated by the formula:

C _f,i (x)＝C _f,unit,i ·d _i (x) (17)

d _i (x)＝V _T C _air,i (x) (18)

V _T : dry and wet deposition rates, m/s, ¹²⁹ i, taking 0.002;

x: the distance from the release point to the calculation point, m.

8. The system of claim 1, wherein the nuclide dose evaluation result output module is specifically configured to calculate a public dose caused by nuclide T, where the public dose caused by tritium includes an inhaled dose and an ingested dose, by the following formula:

H _E(atoms),i (x)＝H _E(inh),i (x)+H _E(ing),f,r,i (x) (19)

1) Inhalation dose, calculated by the formula:

H _E(inh),i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide T;

C _air,i (x) The method comprises the steps of carrying out a first treatment on the surface of the The concentration of the nuclide i in air, bq/m, at the release point x ³ ；

D _inh,i : nuclearThe inhaled dose conversion factor of element i, sv/Bq, H-3, is 4.5X10 ^-11 ；

I _inh : respiration rate, m ³ D, taking 20;

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (20) is calculated by the following formula _air,i (x)：

C _air,i (x) The method comprises the following steps The concentration of the nuclide i in air, bq/m, at the release point x ³ ；

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance from the point to the calculated point, km;

n: experience factor, T, takes 1.2;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

2) The intake dose is calculated by the following formula:

H _E(ing),f,r,i (x)＝C _f,i (x)·D _ing,i ·F _local ·I _f,r (22)

H _E(ing),f,r,i (x) The method comprises the following steps The feeding dose of nuclide i, sv;

C _f,i (x) The method comprises the following steps The concentration of nuclide i in the product, bq/kg or Bq/L;

D _ing,i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f,r : the yield of food in the area, kg or L.

9. The system for evaluating the influence of the radiation environment of a special nuclide in a post-treatment plant according to claim 1, wherein the nuclide dose evaluation result output module is specifically configured to calculate the nuclide by the following formula ¹⁴ The public dose caused by C is given by the formula, ¹⁴ public doses caused by C include inhalation dose, air-submerged external irradiation dose, and intake dose:

H _E(atoms),i (x)＝H _E(inh),i (x)+H _E(ing),f,r,i (x) (23)

1) Inhalation dose, calculated by the formula:

H _E(inh),i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide ¹⁴ C；C _air,i (x) The method comprises the steps of carrying out a first treatment on the surface of the The concentration of the nuclide i in air, bq/m, at the release point x ³ ；

D _inh,i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ D, taking 20 by adults;

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (24) is calculated by _air,i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹⁴ c, taking 1.4;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

H _{E(ex,cloud),i} (x)＝C _air,i (x)·D _ex,cloud,i ·O _ann ·(O _out +(1-O _out )·L _cloud ) (26)

H _{E(ex,cloud),i} (x) The method comprises the following steps The dose caused by the smoke plume immersion of the nuclide i at a distance x from the release point, sv/a;

O _ann : annual residence time, s/a;

D _ex,cloud,i : smoke plume immersion dose conversion factor, sv/(Bq s/m) ³ )；

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

C _air,i (x) The method comprises the following steps The activity concentration, bq/m, of the nuclide i in air at a distance x from the release point ³ ；

3) The intake dose is calculated by the following formula:

H _E(ing),f,r,i (x)＝C _f,i (x)·D _ing,i ·F _local ·I _f,r (27)

D _ing,i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f,r : the yield of food in the area, kg or L.

10. An after-treatment plant special core according to claim 1The element radiation environment influence evaluation system is characterized in that the nuclide dose evaluation result output module is specifically used for calculating nuclides by the following formula ¹²⁹ The public dose caused by the factor I, ¹²⁹ public doses caused by I include inhalation dose, air immersion external irradiation dose, surface deposition external irradiation dose, and intake dose:

H _E(atoms),i (x)＝H _E(inh),i (x)+H _{E(ex,cloud),i} (x)+H _{E(ex,deposit),i} (x)+H _E(ing),f,r,i (x) (28)

1) Inhalation dose, calculated by the formula:

H _E(inh),i (x) The method comprises the following steps An inhaled dose of nuclide i, sv, at a distance x from the release point; i is a nuclide ¹²⁹ I；

D _inh,i : inhalation dose-converting factor of nuclide i, sv/Bq;

I _inh : respiration rate, m ³ /d；

86400: conversion factor, s/d;

O _ann : the annual residence time is 3.15X10 ⁷ s；

x: releasing the distance from the point to the calculated point, m;

c in the formula (29) is calculated by _air,i (x)：

Q: release rate, bq/s;

D _i : diffusion factor of nuclide i at x from release point, s/m ³ ；

X: releasing the distance of the wind direction below the point, km;

n: the empirical factor is used to determine, ¹²⁹ i, 1.42;

λ _i : decay constant of nuclide i, s ^-1 ；

u _a : releasing the wind speed at altitude, km/s;

H _{E(ex,cloud),i} (x)＝C _air,i (x)·D _ex,cloud,i ·O _ann ·(O _out +(1-O _out )·L _cloud ) (31)

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

H _{E(ex,deposit),i} (x)＝d _i (x)·t _discharge ·D _ex,deposit,i ·(O _out +(1-O _out )·L _deposit ) (32)

H _{E(ex,deposit),i} (x) The method comprises the following steps Dose, sv, caused by external irradiation of surface deposition of nuclide i;

t _discharge : deposition time, 3.15X10 ⁷ s；

D _ex,deposit,i : dose-conversion factor of nuclide i, sv/(Bq/m) ² )；

O _out : outdoor useTaking the share of 0.2;

L _deposit : building shielding factors, taking 0.1;

4) The intake dose is calculated by the following formula:

H _E(ing),f,r,i (x)＝C _f,i (x)·D _ing,i ·F _local ·I _f,r (33)

D _ing,i : the feeding dose conversion factor of nuclide i, sv/Bq;

F _local : the portion of food from the local;

I _f,r : yield of food in the area, kg or L;

the nuclide dose evaluation result output module is specifically used for: calculating nuclides ⁸⁵ The public dose caused by Kr, ⁸⁵ the public radiation path caused by Kr is air immersed external radiation, and is calculated by the following formula:

H _{E(ex,cloud),i} (x)＝C _air,i (x)·D _ex,cloud,i ·O _ann ·(O _out +(1-O _out )·L _cloud ) (34)

H _{E(ex,cloud),i} (x) The method comprises the following steps The dose caused by the smoke plume immersion of the nuclide i at a distance x from the release point, sv/a; i is a nuclide ⁸⁵ Kr；

O _ann : annual residence time, s/a;

O _out : taking an outdoor share of 0.2;

L _cloud : taking 0.2 of shielding factor of the building;

x: the distance from the release point to the calculation point, m.