CN106991511A - The recombination radiation source strength backstepping method and system of nuclear power plant's point source line source face source combination - Google Patents

Abstract

The invention discloses a kind of recombination radiation source strength backstepping method and system of nuclear power plant's point source line source face source combination, in this method, the close rate of multiple positions is obtained by detector, normalization radiation source intensity is spatially carried out discrete, optical distance is calculated using ray tracing method, the information such as bond material, buildup factor carry out the calculating of equation group coefficient, and backstepping goes out source strength；Then close rate calculating is carried out to detector position, by the way that measured value and calculated value are carried out linear regression analysis, calculates the key parameters such as standard deviation, slope, intercept, and then calculate quality factor to weigh the acceptable degree of each result of calculation；Propose the Weighted Iterative Methods simultaneously, the error that the larger detector of reduction uncertainty is introduced, using the mode of iteration, above steps may be repeated multiple times until quality factor reach pre-set value, obtains desired radiation source intensity information.

Description

The recombination radiation source strength backstepping method and system of nuclear power plant's point source line source face source combination

Technical field

The present invention relates to the computational methods of radiation source intensity in nuclear power plant and system, and in particular to a kind of nuclear power plant's point source line The recombination radiation source strength backstepping method and system of source face source combination.

Background technology

The active region of the radioactivity of nuclear power plant fuel assembly in pressure vessel, radiation source mainly by fission product, Actinides and activating product composition.In system operation, radiation source is with coolant flow through primary Ioops main system (including pressure Container, main pump, voltage-stablizer, main pipeline etc.), chemical vessel control system etc., Distribution of radiation source is in cooling agent and relevant device table Face.Radiation source radioactivity itself is strong, and the dosage suffered by daily routines of the staff when nuclear power plant normally runs accounts for year total agent 20% or so of amount, and during nuclear power station overhaul, the dosage suffered by staff will account for the 80% of year accumulated dose, in core Mainly radioactive dose is reduced during power plant's overhaul by shortening staff in the residence time of radiation area.

Distribution of radiation source is especially passed through by prolonged than wide using with after overhaul according to engineering in nuclear power plant Test and be increasingly difficult to be inferred to the radiation intensity of each position radiation source, so in very multidata calculating, especially foundation In the calculating of radiation source intensity, because it is difficult to obtain accurate Back ground Information and greatly affected accuracy and practicality, together When, in the case that current protective equipment and means are not very complete at home, also make it that the illuminated risk of staff is big Big increase.

In the prior art, it is necessary to when calculating radiation source intensity, Sources term analysis method typically be used, first, according to radioactive material The generation of matter and disappearance approach determine its generation item (as flowed into item, decay produces item etc.) and disappearance item (such as filtering item, leakage item Deng), and clearly every physical model, nucleon concentration balance equation is then set up to radioactive substance according to above-mentioned items (group), last simultaneous equations (group) solve, but there is substantial amounts of simplification and approximate calculation in these calculating process, so its As a result it is often larger with actual value gap, in practical application in the presence of many obstacles, in addition, in view of radiation source in itself Complicated geometry, radionuclide accurate information are difficult to obtain inside the harm that is caused to human body, nuclear power plant, nuclear power plant is visited When surveying the factors such as the uncertainty of device measured value, the above method is problematic in that in terms of security, accuracy, it would be highly desirable to improved Or propose new radiation source intensity acquiring way.

For these reasons, the present inventor furthers investigate to the method for existing calculating source strength information, rule of thumb, Part radioactive components can be reduced to a point source or one group of point source in usual nuclear power plant, can also be simplified to a line source Or one group of line source, one or one group of face source can also be simplified to, a such as thermal valve can be reduced to a point source, a pipe Road can be reduced to a point source or multiple point sources, can also be simplified to a line source, and some pipelines can also be reduced to one Cylindrical surface source, can carry out sliding-model control, and then carry out source strength according to the information after sliding-model control for face source and line source Backstepping obtains radiation source intensity information, so as to design a kind of nuclear power plant's point source line source face source combination that can solve the problem that above mentioned problem Recombination radiation source strength backstepping method and system.

The content of the invention

In order to overcome above mentioned problem, present inventor has performed studying with keen determination, a kind of nuclear power plant's point source line source face source is designed The recombination radiation source strength backstepping method and system of combination, this method and system can fully ensure the situation of human body radiation safety Under, obtain point source, line source and the source strength data in face source under complex geometry space structure inside nuclear power plant；In this method, in core Detector is placed in precalculated position in power plant, and is also placed in the position with shielded detector, and then obtains radiation source Release the average energy of gamma ray；In addition, the detector of multiple monitoring nuclear power plants radiation value is additionally provided with nuclear power plant, with The close rate of part sampling site is obtained, the mode combined using Point- kernel integral and weighted least-squares method, while normalization is radiated Source strength spatially carries out discrete, judges gamma-rays that each point source, line source and face source release in sky using ray tracing method Between walk distance and calculate optical distance, the information such as bond material, buildup factor carry out equation group coefficient calculating, and then Backstepping goes out source strength；Then the calculated value to close rate at detector position is obtained, linear regression is carried out to measured value and calculated value Analyzing and processing, obtains the key parameters such as standard deviation, slope, intercept, and then obtains that the quality factor of physical meaning can be represented, should Quality factor can weigh the acceptable degree of each result of calculation；A kind of the Weighted Iterative Methods are proposed simultaneously, reduce uncertainty The error that larger detector is introduced, using the mode of iteration, above steps may be repeated multiple times until quality factor meet default bar Part, and then the uncertainty of desired radiation source intensity and radiation field result is obtained, so as to complete the present invention.

In particular it is object of the present invention to provide following aspect：

(1) a kind of recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination, it is characterised in that this method Comprise the following steps：

Step one, the close rate D in nuclear power plant is detected with detector₁,D₂,D₃…D_i,

Step 2, according to the close rate information detected, sets up super containing radiation source intensity as shown in following formula (one) Determine equation group,

(1)

Wherein, the coefficient matrix a of the over-determined systems_i,jObtained by following formula (two) and (three),

(2)

(3)

In formula (three), when radiation source is point source, p=0, M=1, N=1；When radiation source is line source, p=1, N= 1；When radiation source is face source, p=1；

Step 3, radiation source intensity information is obtained by the over-determined systems in least square method calculation procedure two, described Radiation source intensity is following formula (four)

S_j,0=(a_j,i·a_i,j)^-1·a_j,i·D_i(4)

Wherein, D_iRepresent the close rate that i-th of detector detection is obtained；J represents the number of radiation source；M represents radiation source The maximum that number can reach；S_jRepresent the intensity of j-th of radiation source；S_j,0Represent j-th of spoke that initial calculation is not iterated Penetrate the intensity in source；a_i,jCoefficient matrix is represented, is dose response coefficient of j-th of radiation source to i-th of detector；BD(E,L(μ (E),r₀→r_p) buildup factor is represented, it is E and L (μ (E), r₀→r_p) function；L(μ(E),r₀→r_p) optical distance is represented, be μ (E) and r₀→r_pFunction；μ (E) represents section/linear attenuation coefficient；r₀→r_pRepresent radiation source to the distance of sensing point；C (E) fluence-dose conversion factor is represented, is E function；E represents energy, is the gamma rays that radiation source is sent in nuclear power plant Average energy；Represent discrete source strength；M and N represent respectively face source on two-dimensional coordinate in latter two discrete reference axis from Dissipate label；

Preferably, after step 3, methods described also comprises the following steps,

Step 4, according to the close rate at the radiation source intensity information calculating detector position obtained in step 3, D₁′, D₂′,D₃′…D_i′；

The close rate information at detector position that step 5, the close rate information detected to detector and calculating are obtained Linear fit, the linear equation of the both sides relation after being fitted are carried out, and then obtains fitting parameter, the fitting parameter bag Include：Average uncertainty, the goodness of fit and corresponding weight matrix；

Step 6, over-determined systems of the new weight matrix iteration obtained in step 5 into step 2 are added The overdetermined equation of power, and then repeat step two, step 3 and step 4, until obtaining desired radiation source intensity information；

Wherein, D_iThe close rate at i-th of detector position that ' expression is calculated.

(2) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (1), it is special Levy and be, when radiation source is face source, the discrete source strengthObtained by following formula (five)：

(5)；

Wherein, S_UAnd S (M)_V(N) source strength weight factor of the face source on two-dimensional coordinate on discrete rear U coordinate axle is represented respectively With the source strength weight factor in V reference axis；

Preferably, when the face source is cylindrical surface source, S_UAnd S (M)_V(N) obtained respectively by following formula (six) and (seven)：

(6)

(7)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, Z represents the height of cylindrical surface source,Represent circle The angle of Cylindrical source；

Preferably, when the face source is spherical source, S_UAnd S (M)_V(N) obtained respectively by following formula (eight) and (nine)：

(8)

(9)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, θ represents the level angle of spherical source,Represent The vertical angle of spherical source；

Preferably, when the face source is rectangular surfaces source, S_UAnd S (M)_V(N) obtained respectively by following formula (ten) and (11) ：

(10)

(11)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, Z represents the length in rectangular surfaces source, and y represents rectangle The width in face source；

Preferably, when the face source is disc face source, S_UAnd S (M)_V(N) obtained respectively by following formula (12) and (13) ：

(12)

(13)

Wherein, η_1,1、η_1,2、η_3,1And η_3,2Cosine distribution constant is all represented,The angle in disc face source is represented, R represents round The radius in card source.

(3) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (1), it is special Levy and be, the average energy E of the gamma rays sent for radiation source in the nuclear power plant, its measuring method includes following sub-step Suddenly：

Sub-step 1, chooses precalculated position inside nuclear power plant, and the precalculated position is t apart from the distance of radiation source, pre- at this Placement location detector is positioned, the close rate I that the detector is detected is collected₀,

Sub-step 2, fetches the detector, is coated outside it and the precalculated position is placed on after screen layer, collect institute State the close rate I that detector is detected；

Or, the detector is fetched, shield is placed in precalculated position, then the detector is placed on shield It is interior, collect the close rate I that the detector is detected；

Sub-step 3, the I and I obtained according to sub-step 1 and step 2₀, clad or shielding are calculated by following formula (14) The mass attentuation coefficient μ of body,

I/I₀=BDe^-μt(14)

Sub-step 4, according to the result of calculation of sub-step 3, obtains the average energy E for the gamma rays that radiation source is sent.

(4) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (1), it is special Levy and be, calculating the method for the optical distance L includes following sub-step,

Sub-step a, tracking gamma ray walks process from radiation source to sensing point, and record gamma ray passes through radiation area The order in domain,

Sub-step b, calculates the distance of each radiation areas respectively, with reference to the linear taper system of each radiation areas material Number, finally obtains total optical distance L.

(5) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (1), it is special Levy and be, using the over-determined systems in Least Square in Processing step 2, and obtain the process of radiation source intensity information and include Following sub-step：

Sub-step 3-1, by over-determined systemsAX=b is expressed as with the form of matrix；

Sub-step 3-2, seeks the normal equation A of the matrix^TAX=A^TB, i.e. X=(A^TA)^-1A^Tb；

Sub-step 3-3, with the triangle decomposition method solution normal equation of symmetrical matrix, remembers G=A^TA, wherein, G is symmetrical matrix；

Sub-step 3-4, G=LDL is solved using triangle decomposition method^T, wherein L is small triangular matrix, and D is diagonal matrix；

Sub-step 3-5, solves lower triangular matrix equation group:LY₁=A^Tb；

Sub-step 3-6, solves diagonal matrix equation group：DY₂=Y₁；

Sub-step 3-7, solves upper triangular matrix equation group：L^TX=Y₂。

(6) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (2), it is special Levy and be, in step 5, linear fit is carried out by following formula (15),

(15)

Wherein,Represent the close rate of estimation；The slope of estimation is represented, The intercept of estimation is represented,

N represents the maximum that detector number i can reach,Close rate is flat at the detector position that expression is calculated Average,Represent the average value for the close rate that detector is detected.

(7) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (6), it is special Levy and be, in step 5, weighting function is obtained according to uncertainty, then weight matrix W, the power are obtained by weighting function Weight matrix W is obtained by following formula (16),

(16)

Wherein, f represents to be fitted uncertainty, Average fit uncertainty is represented, f_iRepresent the fitting uncertainty of i-th of detector position；；Represent weighting function.

(8) the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to above-mentioned (6), it is special Levy and be,

In step 6, work as S_i＞ 0, and quality factor M stops weighted iteration, and output radiation source strength when reaching maximum Information is spent, the radiation source intensity information now exported is the desired radiation source intensity information；

Wherein, quality factor a M, the quality factor M are all correspondingly made available when performing step 6 every time and passes through following formula (17) are obtained,

(17)

Wherein, R²Represent the goodness of fit,

(9) a kind of recombination radiation source strength backstepping system of nuclear power plant's point source line source face source combination, it is characterised in that the system The recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination described in 1-8 is required for perform claim.

(10) the recombination radiation source strength backstepping system of nuclear power plant's point source line source face source combination according to above-mentioned (9), its It is characterised by, the system includes detector, gamma rays average energy computing module and radiation source intensity computing module；

The detector has multiple, including precalculated position detector and nuclear power plant's radiation value monitoring detector,

The precalculated position detector is arranged in nuclear power plant radiation areas the pre-determined bit that distance is determined between radiation source Put, and dismountable screen layer is optionally coated with outside the precalculated position detector；

The precalculated position detector be used for will the radiation dose rate information transmission that detect to gamma rays average energy Computing module,

Nuclear power plant's radiation value monitoring detector is distributed in the radiation areas of nuclear power plant, for that will separately detect Nuclear power plant's middle dosage rate information transmission to radiation source intensity computing module,

The gamma rays average energy computing module is used for the average energy E for calculating gamma rays,

The radiation source intensity computing module is used to calculate radiation source intensity in nuclear power plant.

The present invention have the advantage that including：

(1) the recombination radiation source strength backstepping method combined according to nuclear power plant's point source line source face source for providing of the present invention can be In the case of fully ensureing human body radiation safety, the point source inside nuclear power plant under complex geometry space structure and the source in face source are obtained Strong data；

(2) the recombination radiation source strength backstepping method that the nuclear power plant's point source line source face source provided according to the present invention is combined passes through many Secondary iterative calculation, it is ensured that the source strength information in the point source, line source and the face source that finally give more is adjacent to actual value, with very high work Journey application value.

Brief description of the drawings

Fig. 1 shows the overall workflow figure according to a kind of preferred embodiment of the invention.

Embodiment

Below by drawings and examples, the present invention is described in more detail.Illustrated by these, the features of the present invention It will be become more apparent from clearly with advantage.

Special word " exemplary " is meant " being used as example, embodiment or illustrative " herein.Here as " exemplary " Illustrated any embodiment should not necessarily be construed as preferred or advantageous over other embodiments.

The recombination radiation source strength backstepping method that the nuclear power plant's point source line source face source provided according to the present invention is combined, this method bag Include following steps：

Step one, the close rate information D that the detector in power plant is detected is received₁,D₂,D₃…D_i, it is above-mentioned many in order to detect Individual close rate in the present invention, can place multiple detectors, it is necessary to use multiple detectors into power plant, can also direct profit With the detector existed in nuclear power plant, the detector existed in nuclear power plant is nuclear power plant's radiation value monitoring detector, It can be combined with using above two mode, be for the status requirement where above-mentioned detector：Radiation source and the position it Between there is no a shield, heretofore described close rate is radiation dose rate.In the present invention, the quantity of the detector is more than nuclear power The quantity of radiation source in factory.

Step 2, according to the close rate information detected, sets up the over-determined systems containing radiation source intensity, the overdetermination Equation group is following formula (one),

(1)

Step 3, radiation source intensity information is obtained by the over-determined systems in least square method calculation procedure two, described Radiation source intensity is following formula (four)

S_j,0=(a_j,i·a_i,j)^-1·a_j,i·D_i(4)

The coefficient matrix a of the over-determined systems_i,jIt is by following formula after Jiang Mianyuan is discrete on radiation space coordinate (2) obtained with (three),

(2)

(3)；

In formula (three), when radiation source is point source, p=0, M=1, N=1；When radiation source is line source, p=1, N= 1；When radiation source is face source, p=1；

In the present invention, due to needing the region for calculating radiation source intensity many, it is necessary to the radiation of measuring and calculating in a nuclear power plant Source also has a lot, in different regions or for different radiation sources, and selection can be caused to be intended chemical conversion point source or line Source or face source, and can be calculated by above-mentioned formula (three), when radiation source is point source, p=0, M=1, N=1； When radiation source is line source, p=1, N=1；When the radiation source is face source, p=1., can not be right when radiation source is point source Radiation source does discrete processes, i.e.,

After step 3, have been able to obtain the strength information of radiation source, but the strength information is possible and inadequate Accurately, so continuing to calculate by following step, to obtain the radiation source intensity information for more pressing close to actual value；

Step 4, according to the close rate at the radiation source intensity information calculating detector position obtained in step 3, D₁′, D₂′,D₃′…D_i′；

The close rate information at detector position that step 5, the close rate information detected to detector and calculating are obtained Linear fit, the linear equation of the both sides relation after being fitted are carried out, and then obtains fitting parameter, the fitting parameter bag Include：Average uncertainty, the goodness of fit and corresponding weight matrix；Heretofore described weight matrix can be interior weight square Battle array or outer weight matrix, its preparation method are consistent, and uncertainty is not by system if difference is outer weight matrix Calculate what is obtained, but the detector error range inputted by operator's means.

Step 6, over-determined systems of the weight matrix iteration obtained in step 5 into step 2 are weighted Overdetermined equation, and then repeat step two, step 3 and step 4, until obtaining desired radiation source intensity information；

In the present invention, D represents the close rate that detector is detected；D_iRepresent the close rate that i-th of detector detection is obtained； I represents the number of detector；J represents the number of radiation source, and m represents the maximum that radiation source number can reach；S represents radiation source Intensity；S_jRepresent the intensity of j-th of radiation source；S_j,0Represent the intensity for j-th of radiation source that initial calculation is not iterated； a_i,jCoefficient matrix is represented, is dose response coefficient of j-th of radiation source to i-th of detector, point source pair is represented in the present invention The response coefficient of detector also illustrates that face source after discrete to the response coefficient of detector；BD(E,L(μ(E),r₀→r_p) represent accumulation The factor, is E and L (μ (E), r₀→r_p) function；L(μ(E),r₀→r_p) optical distance is represented, it is μ (E) and r₀→r_pFunction, That is, optical distance is the function of energy and actual range；μ (E) represents linear attenuation coefficient；r₀→r_pRepresent radiation source to detection The distance of point；C (E) represents fluence-dose conversion factor, is E function；E represents energy, is that radiation source is sent in nuclear power plant The average energy of gamma rays；D_iThe close rate at i-th of detector position that ' expression is calculated；Represent discrete source strength； M and N represent discrete label of the face source on two-dimensional coordinate in latter two discrete reference axis respectively.Wherein, the sensing point is represented The position of detector, is more precisely the position that radiation information is received on detector.

Heretofore described discrete source strengthObtained by following formula (five)：

(5)；

Wherein, S_UAnd S (M)_V(N) source strength weight factor of the face source on two-dimensional coordinate on discrete rear U coordinate axle is represented respectively With the source strength weight factor in V reference axis；

Preferably, when the face source is cylindrical surface source, S_UAnd S (M)_V(N) obtained respectively by following formula (six) and (seven)：

(6)

(7)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, the cosine distribution constant default value is zero, can To be configured according to actual conditions, Z represents the height of cylindrical surface source,Represent the angle of cylindrical surface source；That is,

Preferably, when the face source is spherical source, S_UAnd S (M)_V(N) obtained respectively by following formula (eight) and (nine)：

(8)

(9)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, the cosine distribution constant default value is zero, can To be configured according to actual conditions, θ represents the level angle of spherical source,Represent the vertical angle of spherical source；That is, η is worked as_2,1 S when=0_U(M)=cos θ_M-cosθ_M+1,

Work as η_2,1When ≠ 0：S_U(M) value is：

Work as η_2,1When=0

Work as η_2,1When ≠ 0：

Preferably, when the face source is rectangular surfaces source, S_UAnd S (M)_V(N) obtained respectively by following formula (ten) and (11) ：

(10)

(11)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, the cosine distribution constant default value is zero, can To be configured according to actual conditions, Z represents the length in rectangular surfaces source, and y represents the width in rectangular surfaces source；I.e.

Preferably, when the face source is disc face source, S_UAnd S (M)_V(N) obtained respectively by following formula (12) and (13) ：

(12)

(13)

Wherein, η_1,1、η_1,2、η_3,1And η_3,2Cosine distribution constant is all represented, the cosine distribution constant default value is zero, can To be configured according to actual conditions,The angle in disc face source is represented, R represents the radius in disc face source, i.e.,

Work as η_1,1When=0

Work as η_2,1When ≠ 0：S_U(M) value is

Heretofore described buildup factor is professional term commonly used in the art, can refer to generally containing in this area Justice is explained and calculated, and its calculation formula generally is provided in the present invention as follows：

Wherein K^xFitting formula it is as follows：

K (E, x)=cx^a+d[tanh(x/X_k-2)-tanh(-2)]/[1-tanh(-2)]；

Wherein E is photon energy, MeV；_xFor source point to the distance for calculating point, mfp；B is the product at a mean free path The tired factor；a,c,d,X_kFor empirical parameter, when tiring out the selection of factor coefficient, it can select to use log difference mode, i.e.,：

a(E_a)={ a (E₁)·[log(E₂)-log(E_a)]+a(E₂)·[log(E_a)-log(E₁)]}/[log(E₂)-log (E₁)]

In one preferred embodiment, the average energy E for the gamma rays that radiation source is sent in the nuclear power plant Measuring method includes following sub-step：

Sub-step 1, chooses precalculated position inside nuclear power plant, and the precalculated position is t apart from the distance of radiation source, pre- at this Placement location detector is positioned, the close rate I that the detector is detected is collected₀,

Sub-step 2, fetches the detector, is coated outside it and the precalculated position is placed on after screen layer, collect institute State the close rate I that detector is detected；

Or, the detector is fetched, shield is placed in precalculated position, then the detector is placed on shield It is interior, collect the close rate I that the detector is detected；

Sub-step 3, the I and I obtained according to sub-step 1 and step 2₀, clad or shielding are calculated by following formula (14) The mass attentuation coefficient μ of body,

I/I₀=BDe^-μt(14)

Sub-step 4, according to the result of calculation of sub-step 3, tables look-up and obtains the average energy for the gamma rays that radiation source is sent E.The table tabled look-up can be material section table, and the token is loaded in ANSI/ANS 6.4.3, " Gamma-ray Attenuation Coefficients and Buildup Factor for Engineering Materials”, American Nuclear Society, 16-67 pages of 1991..In the present invention, all use emittance, all with above-mentioned Average energy is calculated, if its capacity volume variance of different zones is larger in nuclear power plant, it may be considered that the region is individually calculated, i.e., single Solely measuring and calculating average energy, individually calculates radiation source intensity.

In one preferred embodiment, calculating the method for the optical distance L includes following sub-step, sub-step a, Track gamma ray and walk process from radiation source to sensing point, record gamma ray passes through the order of radiation areas, that is, passed through Ray tracking method calculates radiation source to sensing point apart from r₀→r_p, wherein r₀The position of radiation source is represented, sensing point is represented Position r_p.Sub-step b, calculates the distance of each radiation areas respectively, with reference to the linear taper coefficient of each radiation areas material, Finally obtain total optical distance L.

Specifically, gamma-rays is calculated when walking distance, describes space with combinatorial geometry method, and by different medium Space is divided into different regions.Obtain respectively the distance between the intersection point of gamma ray and each basic body and entrance Di and With outlet the distance between Do.Obtain all basic body numbering plus and minus with "+" and "-", the process in each region It may include six following steps,

(1) the starting point r of every line₀Region Ipstart determination：

If not having "-" basic body in some region, then in the region, all "+" basic bodies must all have been fulfilled for Point r₀In all "+" basic bodies, then it is considered that the initiation region of ray is the region；If having in the region "-" basic body, then all "+" basic bodies must all are fulfilled for starting point r in the region₀In all "+" basic bodies, and And all "-" basic bodies must all are fulfilled for the starting point r not comprising this ray₀, then the initiation region for thinking ray is the area Domain.

(2) the terminal r of every line_pRegion Ipend determination：

If likewise, not having "-" basic body in some region, then in the region, all "+" basic bodies are all necessary Meet terminal r_pIn all "+" basic bodies, then it is considered that the termination area of ray is the region；If the region In have "-" basic body, then all "+" basic bodies must all are fulfilled for terminal r in the region_pPositioned at all "+" basic bodies In, and all "-" basic bodies must all are fulfilled for the terminal r not comprising this ray_p, then the termination area for thinking ray is The region.

(3) the starting point r of every line₀Determination of the corresponding regional export in region number apart from Zo：

If do not have in gamma-rays initiation region number the basic body conveying ends of "+" all in "-" basic body, initiation region away from It is with a distance from the outlet of the gamma-rays initiation region from reckling in Do.If there is "-" basic body in gamma-rays initiation region, rise first The basic body conveying end for owning "+" in beginning region is minimum in Do, then own "-" basic bodies take import in Di most Small, take the outlet distance that both maximums are the gamma-rays initiation region.

(4) the numbering IP in each region that ray passes through determination：

Terminal is not under outermost areas case, if not having "-" basic body in regional number, and adjacent subarea domain is carried out first Judgement, for all "+" basic bodies, basic body import distance is less than or equal to the import distance in region and less than basic body Outlet apart from when (Di<=Zin<Do), the region is the adjacent area in a upper region, obtains corresponding zone number IP； If there is "-" basic body in gamma-rays regional number, for all "+" basic bodies, basic body import distance is less than or equal to region Import distance and the outlet distance (Di for being less than basic body<=Zin<Do), and to all "-" basic bodies, basic body import Distance is more than zone inlet distance or basic body outlet distance is less than or equal to zone inlet distance (Di>Zin or Do<=Zin) When, the region is the adjacent area in a upper region, obtains corresponding zone number IP.

(5) import in each region that ray passes through is apart from Zi and exports the determination apart from Zo：

If not having "-" basic body in the above-mentioned adjacent area obtained, the regional export distance is the basic body of all "+" Outlet is minimum in Do, and the import distance in the region is the outlet distance in a upper region；If the above-mentioned adjacent region obtained There is "-" basic body in domain, first obtain the basic body conveying end of all "+" reckling in Do, obtaining the basic of all "-" Body import reckling in Di, then takes the outlet distance that both maximums are the region, and the import distance in the region is For the outlet distance in a upper region.

(6) terminal finds all basic body numbering aa of outermost layer under outermost areas case, first, for region Middle "+" basic body includes basic body aa, when "-" basic body does not include basic body aa region, looks for whether there is ray process In region "-" import of basic body distance is more than the import distance (Di (k, minus (i, m)) in region>Zi (k, n)) "-" base Body, if it does, regional export distance takes all "-" basic body import recklings in Di, if it does not, region goes out Mouth distance is ray length.

Trace into r_pPoint region IPend and radiation exit distance be equal to ray length when terminate.So as to obtain γ Ray walks distance.

The number of times of ray crossing area is carried out again and walks the calculating of distance every time：

If the crossing area numbering of ray is not 0, then the gamma-ray distance of walking in the region is equal to zone inlet distance Cut regional export distance, gamma-rays walks number of times and plus 1；If gamma-ray crossing area numbering is 0, stop tracking.

γ section μ are obtained using the material of γ mass attentuation coefficients and Region Medium_n；

Then by above-mentioned record gamma-rays by the process of walking during region, the optical distance in each region is obtained respectively Sum again, i.e.,：Wherein, N represents the quantity of radiation areas, and the quantity is mainly by factory What room internal environment was determined.

In one preferred embodiment, using the over-determined systems in Least Square in Processing step 2, and obtain The process of radiation source intensity information includes following sub-step：

Sub-step 3-1, by over-determined systemsAX=b is expressed as with the form of matrix；

Sub-step 3-2, seeks the normal equation A of the matrix^TAX=A^TB, i.e. X=(A^TA)^-1A^Tb；

Sub-step 3-3, with the triangle decomposition method solution normal equation of symmetrical matrix, remembers G=A^TA, wherein, G is symmetrical matrix；

Sub-step 3-4, G=LDL is solved using triangle decomposition method^T, wherein L is small triangular matrix, and D is diagonal matrix；

Sub-step 3-5, solves lower triangular matrix equation group:LY₁=A^Tb；

Sub-step 3-6, solves diagonal matrix equation group：DY₂=Y₁；

Sub-step 3-7, solves upper triangular matrix equation group：L^TX=Y₂。

Wherein, X=(A^TA)^-1A^TB withIt is corresponding, pass through the sub-step 3-1 The evaluation of radiation source intensity is obtained to sub-step 3-7, heretofore described least square method is general in this area Overdetermined equation calculation method.

In one preferred embodiment, in step 5, linear fit is carried out by following formula (15),

(15)

Wherein,Represent the close rate of estimation；The slope of estimation is represented, Represent The intercept of estimation,

N represents the maximum that detector number i can reach,Close rate is averaged at the detector position that expression is calculated Value,Represent the average value for the close rate that detector is detected.

In one preferred embodiment, after linear fit, the average not true of linear fit is also respectively obtained Fixed degree, the goodness of fit, quality factor, weighting function and corresponding weight matrix, the quality factor represent current iteration calculating Confidence level.In step 5, weighting function is obtained according to uncertainty, then by weighting function acquisition weight matrix W, it is described Weight matrix W is obtained by following formula (16),

(16)

Wherein, f represents to be fitted uncertainty,f_iRepresent the fitting uncertainty of i-th of detector position；Average fit uncertainty is represented, Represent weighting function.

In one preferred embodiment, in step 6, the judgement of the desired radiation source intensity information is obtained Condition is to work as S_iDuring ＞ 0, and quality factor M reaches maximum, that is, works as S_i＞ 0, and quality factor M stop when reaching maximum plus Iteration, and output radiation source strength information are weighed, the radiation source intensity information is exactly the desired radiation source intensity finally given, It is closest to the radiation source intensity of actual value.

It is an object of the invention to obtain the radiation source intensity closest to actual value, and the radiation source intensity that step 3 is obtained Reliability ratio it is relatively low, its error between actual value can be than larger, so the accuracy in order to improve the numerical value, that is, obtain Closest to the radiation source intensity of actual value, step 4 is given to the weighted iteration process of step 6 in the present invention, and finally set The condition of iteration ends is determined, to reduce workload as far as possible in the case of ensureing that result is accurate, has shortened the activity duration, improve number According to the efficiency of acquisition.According to the criterion of above-mentioned the Weighted Iterative Methods and iteration ends.In addition, the radiation obtained in the present invention Source strength than Sources term analysis method obtain radiation source intensity it is more accurate, more press close to actual value, ensure that acquisition value with Actual value is within an order of magnitude.In one preferred embodiment, one is all correspondingly made available when performing step 6 every time Individual quality factor M, the quality factor M is obtained by following formula (17),

(17)

Wherein, R²Represent the goodness of fit,

In one preferred embodiment, over-determined systemsMatrix form see below formula (18)

(18)

Wherein, ε represents the error that each detector is introduced；Consider caused by physics meaning, actually each sensing point Error may be considered caused by radiation source, then above-mentioned equation simplification is following formula (19),

(19),

And then it can be found that, coefficient matrix a_i,jDose response coefficient of j-th of radiation source to i-th of detector is equivalent to, Wherein, the dose response coefficient of detector is calculated using Point- kernel integral technology, and the Point- kernel integral technology meter is this area Middle conventional computational methods.

The recombination radiation source strength backstepping system that a kind of nuclear power plant's point source line source face source provided according to the present invention is combined, this is Unite for the recombination radiation source strength backstepping method for performing the above nuclear power plant's point source line source face source combination of the present invention.

Preferably, the system includes detector, gamma rays average energy computing module and radiation source intensity computing module；

The detector has multiple, including precalculated position detector and nuclear power plant's radiation value monitoring detector,

The precalculated position detector is arranged in nuclear power plant radiation areas the pre-determined bit that distance is determined between radiation source Put, and dismountable screen layer is optionally coated with outside the precalculated position detector；The precalculated position distance radiation The distance in source can occur in follow-up calculating as known quantity；

The precalculated position detector be used for will the radiation dose rate information transmission that detect to gamma rays average energy Computing module, to calculate gamma rays average energy；

Nuclear power plant's radiation value monitoring detector is distributed in the radiation areas of nuclear power plant, respectively the institute in the present invention The key position stated, for the nuclear power plant's middle dosage rate information transmission that will separately detect to radiation source intensity computing module,

The gamma rays average energy computing module is used for the average energy E for calculating gamma rays,

The radiation source intensity computing module is used to calculate radiation source intensity in nuclear power plant.

Experimental example：

Using NB281 rooms in No. 1 unit nuclear island of Daya Bay nuclear power plant as experimental subjects, the room is in nuclear island control zone For placing the place that radioactive wastewater collecting vessel is housed, wastewater collection bucket is a hydrostatic column, inner radiation fluid supply It is 0.7586E+10MeV/cm by force³.s (or 4.2898E+14/s).The top half of the hydrostatic column is reduced to 2 points Source, middle part is reduced to 1 cylindrical surface source, and the latter half is reduced to 2 line sources, is set in wastewater collection bucket center section every 50cm A detector is put, totally five detectors, the probe value that each detector is obtained is respectively 2.032mSv/hr, 0.685mSv/ Hr, 0.255mSv/hr, 0.1446mSv/hr, 0.0929mSv/hr, are the D in the present invention₁,D₂,D₃,D₄,D_5,According to this hair The average energy acquisition methods and system of bright offer obtain average energy for 1.3MeV, the source strength backstepping side provided using the present invention Method and system, the 2 point source source strengths respectively obtained are respectively 7.0856E+13MeV/s, 7.1763E+13MeV/s, 2 line source sources By force be respectively 2.6677E+12MeV/ (cm.s) (or 7.1228E+13MeV/s), 2.7132E+12MeV/ (cm.s) (or 7.2441E+13MeV/s), the source strength in 1 face source is 2.9225E+10MeV/ (cm².s) (or 7.3413E+13MeV/s).

It was found from final result, five obtained radiation source intensity sums and the radiation intensity actual value base of the radiation source This is consistent, it is possible to illustrate that the method and system of the invention provided result in the radiation source intensity information of actual value.

Above in association with preferred embodiment the present invention is described, but these embodiments are only exemplary , only play illustrative effect.On this basis, a variety of replacements and improvement can be carried out to the present invention, these each fall within this In the protection domain of invention.

Claims (10)

1. a kind of recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination, it is characterised in that this method includes Following steps：

Step one, the close rate D in nuclear power plant is detected with detector₁,D₂,D₃…D_i；

Step 2, according to the close rate information detected, sets up the overdetermination side containing radiation source intensity as shown in following formula (one) Journey group,

$D_i=\underset{j=1}{\overset{m}{\&Sigma;}}{a}_{i,j}{S}_j$ (1)

Wherein, the coefficient matrix a of the over-determined systems_i,jObtained by following formula (two) and (three),

$a_{i,j}=a_{i,j}^{1,1}+a_{i,j}^{1,2}+\mathrm{....}+a_{i,j}^{1,MaxM}+a_{i,j}^{2,1}+a_{i,j}^{2,2}+\mathrm{...}+a_{i,j}^{2,MaxM}+\mathrm{...}+a_{i,j}^{MaxN,1}+a_{i,j}^{MaxN,2}+\mathrm{...}+a_{i,j}^{MaxN,MaxM}$

(2)；

$a_{i,j}^{M,N}=\frac{{\left(S_{i,j}^{M,N}\right)}^p\&CenterDot;e^{-L(E_l,r_0\&RightArrow;r_p)}}{4\mathrm{\&pi;}|r_0\&RightArrow;r_p{|}^2}BD(E_l,L(E_l,r_0\&RightArrow;r_p\left)\right)C\left(E_l\right)$ (3)；

In formula (three), when radiation source is point source, p=0, M=1, N=1；When radiation source is line source, p=1, N=1；When When radiation source is face source, p=1；

Step 3, by the over-determined systems in Least Square in Processing step 2, obtains the radiation source intensity as shown in following formula (four) Spend information,

S_j,0=(a_j,i·a_i,j)^-1·a_j,i·D_i(4)；

Wherein, D_iRepresent the close rate that i-th of detector detection is obtained；J represents the number of radiation source；M represents radiation source number energy The maximum reached；S_jRepresent the intensity of j-th of radiation source；S_j,0Represent j-th of radiation source that initial calculation is not iterated Intensity；a_i,jCoefficient matrix is represented, is dose response coefficient of j-th of radiation source to i-th of detector；BD(E,L(μ(E),r₀ →r_p) buildup factor is represented, it is E and L (μ (E), r₀→r_p) function；L(μ(E),r₀→r_p) represent optical distance, be μ (E) and r₀→r_pFunction；μ (E) represents section/linear attenuation coefficient；r₀→r_pRepresent radiation source to the distance of sensing point；C (E) is represented Fluence-dose conversion factor, is E function；E represents energy, is the average energy of the gamma rays that radiation source is sent in nuclear power plant Amount；Represent discrete source strength；M and N represent discrete label of the face source on two-dimensional coordinate in latter two discrete reference axis respectively；

Preferably, after step 3, methods described also comprises the following steps,

Step 4, according to the close rate at the radiation source intensity information calculating detector position obtained in step 3, D '₁,D′₂, D′₃…D′_i；

Step 5, the close rate information detected to detector and the close rate information calculated at obtained detector position are carried out Linear fit, the linear equation of the both sides relation after being fitted, and then fitting parameter is obtained, the fitting parameter includes：It is flat Equal uncertainty, the goodness of fit and corresponding weight matrix；

Step 6, by over-determined systems of the weight matrix iteration obtained in step 5 into step 2, the overdetermination weighted Equation, and then repeat step two, step 3 and step 4, until obtaining desired radiation source intensity information；

Wherein, D '_iThe close rate at i-th of detector position that expression is calculated.

2. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 1, its feature It is, when radiation source is face source, the discrete source strengthObtained by following formula (five)：

$S_{i,j}^{M,N}=\frac{S_U\left(M\right)\&CenterDot;S_V\left(N\right)}{\left(\underset{M=1}{\overset{MaxM}{\&Sigma;}}\underset{N=1}{\overset{MaxN}{\&Sigma;}}{S}_U\right(M)\&CenterDot;S_V(N\left)\right)}$ (5)；

Wherein, S_UAnd S (M)_V(N) source strength weight factor and V of the face source on two-dimensional coordinate on discrete rear U coordinate axle are represented respectively Source strength weight factor in reference axis；

Preferably, when the face source is cylindrical surface source, S_UAnd S (M)_V(N) obtained respectively by following formula (six) and (seven)：

$S_U\left(M\right)={\&Integral;}_{z_M}^{z_{M+1}}\cos ({\mathrm{\&eta;}}_{2,1}\&CenterDot;(z-{\mathrm{\&eta;}}_{2,2}\left)\right)dz,M=1,2,3,\mathrm{...}MaxM$ (6)

(7)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, Z represents the height of cylindrical surface source,Represent cylindrical surface source Angle；

Preferably, when the face source is spherical source, S_UAnd S (M)_V(N) obtained respectively by following formula (eight) and (nine)：

$S_U\left(M\right)={\&Integral;}_{{\mathrm{\&theta;}}_M}^{{\mathrm{\&theta;}}_{M+1}}\cos \&lsqb;{\mathrm{\&eta;}}_{2,1}\&CenterDot;(\mathrm{\&theta;}-{\mathrm{\&eta;}}_{2,2})\&rsqb;\&CenterDot;sin\mathrm{\&theta;}\&CenterDot;d\mathrm{\&theta;},M=1,2,3,...MaxM$ (8)

(9)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, θ represents the level angle of spherical source,Represent spherical source Vertical angle；

Preferably, when the face source is rectangular surfaces source, S_UAnd S (M)_V(N) obtained respectively by following formula (ten) and (11)：

$S_U\left(M\right)={\&Integral;}_{z_M}^{z_{M+1}}\cos ({\mathrm{\&eta;}}_{2,1}\&CenterDot;(z-{\mathrm{\&eta;}}_{2,2}\left)\right)dz,M=1,2,3,...MaxN$ (10)

$S_V\left(N\right)={\&Integral;}_{y_N}^{y_{N+1}}\cos ({\mathrm{\&eta;}}_{3,1}\&CenterDot;(y-{\mathrm{\&eta;}}_{3,2}\left)\right)dy,N=1,2,3,...MaxN$ (11)

Wherein, η_2,1、η_2,2、η_3,1And η_3,2Cosine distribution constant is all represented, Z represents the length in rectangular surfaces source, and y represents rectangular surfaces source Width；

Preferably, when the face source is disc face source, S_UAnd S (M)_V(N) obtained respectively by following formula (12) and (13)：

(12)

$S_V\left(N\right)={\&Integral;}_{R_N}^{R_{N+1}}R\&CenterDot;cos({\mathrm{\&eta;}}_{1,1}\&CenterDot;(R-{\mathrm{\&eta;}}_{1,2}\left)\right)dR,N=1,2,3,...MaxN$ (13)

Wherein, η_1,1、η_1,2、η_3,1And η_3,2Cosine distribution constant is all represented,The angle in disc face source is represented, R represents disc face source Radius.

3. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 1, its feature It is, the average energy E of the gamma rays sent for radiation source in the nuclear power plant, its measuring method includes following sub-step Suddenly：

Sub-step 1, chooses precalculated position inside nuclear power plant, and the precalculated position is t apart from the distance of radiation source, in the pre-determined bit Placement location detector, collects the close rate I that the detector is detected₀,

Sub-step 2, fetches the detector, is coated outside it and the precalculated position is placed on after screen layer, collects described visit Survey the close rate I that device is detected；

Or, the detector is fetched, shield is placed in precalculated position, then the detector is placed in shield, receive Collect the close rate I that the detector is detected；

Sub-step 3, the I and I obtained according to sub-step 1 and step 2₀, the matter of clad or shield is calculated by following formula (14) Measure attenuation coefficient mu,

I/I₀=BDe^-μt(14)

Sub-step 4, according to the result of calculation of sub-step 3, obtains the average energy E for the gamma rays that radiation source is sent.

4. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 1, its feature It is, calculating the method for the optical distance L includes following sub-step,

Sub-step a, tracking gamma ray walks process from radiation source to sensing point, and record gamma ray passes through radiation areas Sequentially,

Sub-step b, calculates the distance of each radiation areas respectively, with reference to the linear taper coefficient of each radiation areas material, most Total optical distance L is obtained afterwards.

5. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 1, its feature It is, using the over-determined systems in Least Square in Processing step 2, and obtains the process of radiation source intensity information including such as Lower sub-step：

Sub-step 3-1, by over-determined systemsAX=b is expressed as with the form of matrix；

Sub-step 3-2, seeks the normal equation A of the matrix^TAX=A^TB, i.e. X=(A^TA)^-1A^Tb；

Sub-step 3-3, with the triangle decomposition method solution normal equation of symmetrical matrix, remembers G=A^TA, wherein, G is symmetrical matrix；

Sub-step 3-4, G=LDL is solved using triangle decomposition method^T, wherein L is small triangular matrix, and D is diagonal matrix；

Sub-step 3-5, solves lower triangular matrix equation group:LY₁=A^Tb；

Sub-step 3-6, solves diagonal matrix equation group：DY₂=Y₁；

Sub-step 3-7, solves upper triangular matrix equation group：L^TX=Y₂。

6. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 1, its feature It is, in step 5, linear fit is carried out by following formula (15),

${\hat{D}}^{\&prime;}=\hat{a}+\hat{b}D$ (15)

Wherein,Represent the close rate of estimation；The slope of estimation is represented, $\hat{a}=\frac{1}{n}\underset{i=1}{\overset{n}{\&Sigma;}}{D}_i-\left(\frac{1}{n}\underset{i=1}{\overset{n}{\&Sigma;}}{D}^{\&prime;}\right)\hat{b};$ Expression is estimated The intercept of meter, $\hat{b}=\frac{S_{D^{\&prime;}D}}{S_{D^{\&prime;}{D}^{\&prime;}}};$ $S_{D^{\&prime;}{D}^{\&prime;}}=\underset{i=1}{\overset{n}{\&Sigma;}}{(D_i^{\&prime;}-{\stackrel{\&OverBar;}{D}}^{\&prime;})}^2;S_{D^{\&prime;}D}=\underset{i=1}{\overset{n}{\&Sigma;}}(D_i-\stackrel{\&OverBar;}{D})(D_i^{\&prime;}-{\stackrel{\&OverBar;}{D}}^{\&prime;});$

N represents the maximum that detector number i can reach,The average value of close rate at the detector position that expression is calculated,Represent the average value for the close rate that detector is detected.

7. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 6, its feature It is, in step 5, weighting function is obtained according to uncertainty, then weight matrix W, the weight are obtained by weighting function Matrix W is obtained by following formula (16),

(16)

Wherein, f represents to be fitted uncertainty, Average fit uncertainty is represented, f_iRepresent the fitting uncertainty of i-th of detector position；Represent weighting function；.

8. the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination according to claim 6, its feature It is,

In step 6, work as S_i＞ 0, and quality factor M stops weighted iteration when reaching maximum, and output radiation source strength is believed Breath, the radiation source intensity information now exported is the desired radiation source intensity information；

Wherein, quality factor a M, the quality factor M are all correspondingly made available when performing step 6 every time and passes through following formula (ten Seven) obtain,

$M=\frac{R^2}{{(\stackrel{\&OverBar;}{f}\&CenterDot;(\hat{a}-1)\&CenterDot;\hat{b})}^2}$ (17)

Wherein, R²Represent the goodness of fit, $R^2=1-\frac{RSS}{TSS},TSS=\underset{i=1}{\overset{n}{\&Sigma;}}{(D_i-\stackrel{\&OverBar;}{D})}^2,$ $RSS=\underset{i=1}{\overset{n}{\&Sigma;}}{(D_i-D_i^{\&prime;})}^2.$

9. a kind of recombination radiation source strength backstepping system of nuclear power plant's point source line source face source combination, it is characterised in that the system is used for Perform claim requires the recombination radiation source strength backstepping method of nuclear power plant's point source line source face source combination described in 1-8.

10. the recombination radiation source strength backstepping system of nuclear power plant's point source line source face source combination according to claim 9, its feature It is, the system includes detector, gamma rays average energy computing module and radiation source intensity computing module；

The detector has multiple, including precalculated position detector and nuclear power plant's radiation value monitoring detector,

The precalculated position detector is arranged in nuclear power plant radiation areas the precalculated position that distance is determined between radiation source, and Dismountable screen layer is optionally coated with outside the precalculated position detector；

Radiation dose rate information transmission to the gamma rays average energy that the precalculated position detector is used to detect is calculated Module,

Nuclear power plant's radiation value monitoring detector is distributed in the radiation areas of nuclear power plant, for by the nuclear power separately detected Factory's middle dosage rate information transmission to radiation source intensity computing module,

The gamma rays average energy computing module is used for the average energy E for calculating gamma rays,

The radiation source intensity computing module is used to calculate radiation source intensity in nuclear power plant.