JP2015219046A - Radioactive waste radioactivity measuring method and radioactive waste radioactivity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radioactive waste radioactivity measuring method and a radioactive waste radioactivity measuring device capable of ensuring accurate quantization even if a radioactivity concentration distribution is present in a waste container.SOLUTION: A radioactive waste radioactivity measuring method comprises: a radiation energy spectrum analysis procedure of simulating a measurement of energy spectrum of radiations leaking from within a storage container outside of the storage container and analyzing the radiation energy spectrum in a state of storing radioactive waste in the storage container; a radiation energy spectrum measuring procedure; a radiation energy spectrum search procedure of comparing a radiation energy spectrum analysis result with a radiation energy spectrum measuring result while referring to the radiation energy spectrum analysis result, repeating a search of the radiation energy spectrum analysis result on the basis of a difference, and determining the radiation energy spectrum analysis result small in the difference from the radiation energy spectrum measuring result; and a radioactivity estimation procedure of estimating a radiation dose or a radioactivity concentration on the basis of the determined radiation energy spectrum analysis result.

Description

  The present invention relates to a radioactivity measurement method and apparatus for radioactive waste, and more particularly, a radioactivity suitable for measuring the radioactivity concentration of radioactive waste generated with decommissioning of nuclear power generation facilities with high accuracy. The present invention relates to a radioactivity measurement method and apparatus for waste.

  In the decommissioning of nuclear power generation facilities, a large amount of waste materials such as metal materials and concrete are generated with the dismantling of the facilities. Since these wastes include those that have been activated and contaminated, it is necessary to measure their radioactivity concentration and to treat and dispose of them according to the level of radioactivity concentration. For example, wastes with a relatively low level of radioactivity, such as used ion exchange resins and filters, are classified as L2 wastes and disposed of in concrete pits installed in shallow areas relatively close to the ground surface. Is made.

  Conventionally, these wastes have been stored in drums and simultaneously filled with mortar. For the waste housed in the drum, gamma rays derived from the waste body are measured in a non-destructive manner outside the drum, and the radioactivity and radioactivity concentration are quantified from the measurement results. As a method of quantifying the radioactive concentration of waste contained in a drum, the radiation emitted from the radioactive waste is measured as an energy spectrum while rotating the drum, using the rotational symmetry of the drum. There is one that evaluates the attenuation of radiation based on the ratio of scattered ray intensity and non-scattered ray intensity obtained from the spectrum and measures the radioactivity of the waste (see, for example, Patent Document 1).

JP 2000-56025 A

  By the way, in the case of the drum can which accommodated the conventional waste body, since a clearance gap is produced when it accommodates in the buried disposal site which embeds a drum can, there exists a subject that a storage place is not used effectively. For this reason, it replaces with a drum can and exists in the direction where a square container is utilized as a storage container.

  When a waste body is stored in a container as well as a rectangular container, a radioactive concentration distribution may be generated in the container. It is not difficult to imagine that when measuring and evaluating radioactivity assuming that the concentration in the container is uniform without considering the concentration distribution, an evaluation error may occur. According to the above-described prior art, measurement is performed by rotating the drum can to suppress the influence of the concentration distribution and approximate the uniform concentration.

  In the case of a square container, since there is no rotational symmetry like a drum can, it is difficult to apply the above-described conventional technology. In addition, when there is a concentration distribution in the container, there is a problem that the influence cannot be evaluated.

  The present invention has been made on the basis of the above-described matters, and its purpose is to determine the radioactive concentration of the radioactive waste housed in the waste container when the radioactive concentration distribution exists in the container. An object of the present invention is to provide a radioactivity measurement method and apparatus for radioactive waste that can be accurately quantified.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, in the radioactivity measurement method for radioactive waste stored in a storage container, the radioactive waste is stored in a storage container. The radiation energy spectrum analysis procedure for analyzing the radiation energy spectrum by simulating the measurement of the energy spectrum of radiation leaking from the inside of the storage container outside the storage container, and the radiation analyzed by the energy spectrum analysis procedure A radiation energy spectrum analysis result storing procedure for storing an energy spectrum analysis result in a storage device, and a radiation energy spectrum leaking from the inside of the storage container outside the storage container in a state where the radioactive waste is stored in the storage container. Radiation energy spectrum measurement procedure to be measured and In response to the radiation energy spectrum analysis result storage procedure, the radiation energy spectrum analysis result stored in the storage device is read out, and the radiation energy spectrum analysis result read out by the radiation energy spectrum readout procedure is read out. Refer to the radiation energy spectrum measurement result measured by the radiation energy spectrum measurement procedure, derive a difference, repeat the search for the radiation energy spectrum analysis result based on the derived difference, and compare with the radiation energy spectrum measurement result. Radiation energy spectrum search procedure for determining the radiation energy spectrum analysis result having a small difference, and radiation energy spectrum analysis determined by the radiation energy spectrum search procedure Based on results, characterized by comprising a radiation estimation procedure for estimating the amount of radioactivity or radioactive concentration.

  According to the present invention, it is possible to accurately estimate / evaluate the radioactivity concentration of a radioactive waste housed in a waste container even if the radioactivity concentration distribution exists in the waste container.

It is a system conceptual diagram which shows an example of the measurement system using 1st Embodiment of the radioactivity measurement method and apparatus of the radioactive waste of this invention. It is a flowchart figure which shows an example of the processing flow of 1st Embodiment of the radioactivity measurement method and apparatus of the radioactive waste of this invention. In the first embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention, it is a system conceptual diagram showing an example of a region dividing method in a container when the behavior of radiation is evaluated by simulation. It is a system conceptual diagram which shows an example of the method of collating and estimating a calculation spectrum and an actual measurement spectrum in 1st Embodiment of the radioactivity measurement method and apparatus of the radioactive waste of this invention. An example of a method for collating and estimating a calculated spectrum and an actually measured spectrum by using two gamma ray detectors for energy spectrum measurement in the first embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention It is a system conceptual diagram shown. The system which shows an example of the method of implementing the measurement in several directions using the gamma ray detector for one energy spectrum measurement in 1st Embodiment of the radioactivity measurement method and apparatus of the radioactive waste body of this invention It is a conceptual diagram. Using the first embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention, gamma ray detectors for energy spectrum measurement are arranged on each side surface of the container, respectively, to enable measurement in a plurality of directions. It is a conceptual diagram which shows an example of a structure of a measurement system. Using the first embodiment of the radioactive waste radioactive measuring method and apparatus of the present invention, two gamma ray detectors for energy spectrum measurement are arranged on each side of the container, and measurement in multiple directions is possible It is a conceptual diagram which shows an example of a structure of the measurement system made into. The concept which showed an example of the display screen which displays the measurement condition and the estimation / evaluation condition on a screen in the measurement system using the radioactivity measurement method and apparatus of the first embodiment of the present invention FIG. It is a conceptual diagram which shows an example of a structure of the measurement system using 2nd Embodiment of the radioactivity measurement method and apparatus of the radioactive waste of this invention. It is a system conceptual diagram which shows an example of the method of implementing the measurement which made object the drum can in 3rd Embodiment of the radioactivity measurement method and apparatus of the radioactive waste of this invention.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the radioactive waste body radioactivity measurement method and apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a system conceptual diagram showing an example of a measurement system using the first embodiment of the radioactivity measurement method and apparatus of the present invention, and FIG. 2 is the radioactivity measurement method of the radioactivity waste according to the present invention. FIG. 3 is a flow chart showing an example of the processing flow of the first embodiment of the apparatus, and FIG. 3 shows the radiation behavior in the first embodiment of the radioactive waste body measuring method and apparatus of the present invention by simulation. FIG. 4 is a conceptual diagram of a system showing an example of a region dividing method in a container for evaluation. FIG. 4 shows a calculation spectrum and an actual measurement spectrum in the first embodiment of the radioactive waste radioactive measuring method and apparatus of the present invention. It is a system conceptual diagram which shows an example of the method of collation estimation.

  As shown in FIG. 1, the measurement system using this embodiment includes a waste container 1 that stores radioactive waste, and a gamma ray energy spectrum derived from radionuclides in the waste container 1. 1, a gamma ray detector 2 that is detected from the outside, an energy spectrum measuring device 3 that measures an energy spectrum of gamma rays based on a signal from the gamma ray detector 2, an actual spectrum data 4 that is measured by the energy spectrum measuring device 3, An energy spectrum calculation device 5 for simulating that the gamma ray energy spectrum from the waste body and the waste container 1 is measured from the outside of the waste container 1, and calculated spectrum data 6 calculated by the energy spectrum calculation device 5; , A database 7 for storing the calculated spectrum data 6, and a calculation scan read from the database 7. And Kutorudeta 6, the energy spectrum measuring device 3 detects the gamma ray detector 2 compares the measured spectrum data 4 measured, and a radioactivity of comparator 8 to evaluate the amount of radioactivity or radioactive concentration. Here, the measured spectrum data 4 and the calculated spectrum data 6 can be represented by characteristics in which the horizontal axis indicates the energy width and the vertical axis indicates the gamma ray count rate.

  Next, the processing flow of the measurement system using this embodiment will be described with reference to FIGS. In the present embodiment, when there is a distribution of radioactivity concentration in the waste container 1, the radioactivity amount or radioactivity concentration in the waste container 1 is estimated / evaluated. For this purpose, the radiation behavior is simulated in advance, and the evaluation result is stored in the database 7 and used.

  First, the energy spectrum calculation device 5 constructs a calculation region simulating the waste container 1 and the waste as a prior simulation. Area division is performed on this calculation area (step S101). Specifically, as shown in FIG. 3, the waste container inner area 1 ′ inside the waste container 1 is used as a calculation area, which is divided into 3 × 3 × 3 areas. Each divided region is labeled with a divided region R1, R2,. By dividing the region in this way, it is possible to consider the influence of the density distribution. The number of divisions and the division size are set by the user depending on the size of the waste container 1 and the accuracy of the evaluation.

  Returning to FIG. 2, the energy spectrum calculation device 5 performs spectrum calculation for each of the divided regions R1, R2,... (Step S102). Specifically, as shown in FIG. 3, assuming that there is a radioactive substance in only one divided region among the divided regions R1, R2,..., Gamma rays flying from that region are disposed of the waste container 1. The energy spectrum measured and measured from outside is simulated by calculation. This calculation is performed for all the divided regions, and the energy spectrum derived from each region is stored in the database 7 as the calculated spectrum data 6.

  Returning to FIG. 2, the gamma ray energy spectrum is actually measured from the outside of the waste container 1 by the gamma ray detector 2 and the energy spectrum measuring device 3 to obtain actually measured spectrum data 4 (step S103).

  Next, processing after the measurement is performed is executed. First, the radioactivity comparison device 8 reads out the calculated spectrum data (step S104). Specifically, the calculated spectrum data 6 is read from the database 7.

  The radioactivity amount comparison device 8 sets initial conditions (step S105). Specifically, since the concentration distribution is unknown at the beginning of the calculation, the initial condition is set by a method such as setting a uniform concentration distribution or giving a concentration distribution by applying a weighting factor to each divided area by a random number. Set.

  The radioactivity amount comparison apparatus 8 performs the calculation spectrum synthesis (step S106). Specifically, based on the initial condition set in (Step S105), the calculated spectrum data 6 is synthesized (linear combination) by the following formula 1 to obtain the calculated spectrum synthesized value Scalc.

Here, si represents an energy spectrum from each divided region R1, R2,..., And ai represents a weighting factor for the energy spectrum from each divided region R1, R2,.

  The concept of the processing method according to Equation 1 described above is shown in FIG. 4, where the calculated spectrum s1 indicates the energy spectrum from the divided region R1, and the calculated spectrum s2 indicates the energy spectrum from the divided region R2. Here, since the gamma rays emitted from the radioactive materials in the respective divided regions do not interfere with each other, the actual spectrum actually measured by the gamma ray detector 2 and the energy spectrum measuring instrument 3 is as shown in Equation 1. It can be expressed as the sum of contributions by gamma rays from each region. In actual measurement, there is a possibility of pile-up, but in the case of the radioactive waste targeted here, there is no problem because the amount of gamma rays emitted is small.

  Returning to FIG. 2, the radioactivity amount comparison device 8 performs a comparison process between the synthesized calculated spectrum (calculated spectrum synthesized value Scalc) and the actually measured spectrum 4 (step S107). Specifically, for example, the difference between the calculated spectrum synthesized based on the set initial condition and the actually measured spectrum is compared. The difference between the two spectra is obtained by, for example, equally dividing the entire energy range, which is the horizontal axis of the energy spectrum, by the minute section width, and taking the square error of the gamma ray count rate on the vertical axis for each minute section width showing the same energy value. Calculate the sum of the squared errors over the entire spectrum. The difference between the sum of the square errors and a preset threshold value is compared.

  The radioactivity amount comparison device 8 determines whether or not the sum of square errors is equal to or less than a threshold value (step S108). If the sum of the square errors is equal to or less than the threshold value, the process proceeds to (Step S109). Otherwise, the process proceeds to (Step S110).

  When the total sum of square errors is less than or equal to the threshold, the radioactivity amount comparison device 8 determines the radioactivity amount or radioactivity concentration of each region from the spectrum of each of the divided regions R1, R2,. S109). After executing (Step S109), the process is terminated.

  On the other hand, when the sum of the square errors is not less than or equal to the threshold value in (Step S108), the radioactivity amount comparison device 8 changes the weight of the calculated spectrum in each region (Step S110). Specifically, the value of the weighting factor of the initial condition set in (Step S105) is changed. After executing (Step S110), the process proceeds to (Step S106), and the calculated spectrum is synthesized again, and (Step S107) and (Step S108) are executed. According to the above flow, repeated calculation is performed (searching for a radiation energy spectrum), and an optimal calculation spectrum (calculated spectrum composite value Scalc) is estimated. Evaluate the radioactivity or radioactivity concentration from the estimated synthetic spectrum.

  As a method of changing the weighting factor in (Step S110), a method of updating and evaluating the weighting factor of each region with a certain step width can be considered. The radioactivity concentration of radioactive waste stored in the waste container 1 has an upper limit value and a lower limit value that are determined according to the level, so select a weighting factor to satisfy the condition of being within that range. do it.

  Another method for changing the weighting coefficient is a method using a probabilistic estimation method. For example, a certain divided area Ri (i = 1, 2,...) Is randomly selected by a random number or the like, and weighting factors in the divided area Ri are set to 0.0, 0.5, 1.0, 1.5 in advance. ················································································································· The calculation of the probability is performed by, for example, Expressions 2 and 3 similar to Gibbs sampling which is a probabilistic estimation method in image processing described below.

Here, wl represents a weighting coefficient and is defined by wl∈Ω. Ω represents a set of weighting factors such as 0.0, 0.5, 1.0, 1.5,. T is an arbitrary coefficient. Sexp represents the measured spectrum 4. M represents an index of each energy width when the energy spectrum is divided by a certain width in the energy direction.

  Which weight coefficient is selected is determined by a random number according to the calculated probability. In this case, the greater the probability, the higher the possibility that the weighting factor will be selected. The calculation spectrum is synthesized using the weighting factor changed in this way, and the comparison evaluation is repeatedly performed (the search for the radiation energy spectrum is performed), and the final convergence value is used as the estimated solution. The amount of radioactivity or radioactivity concentration is determined from the concentration distribution as a solution. By this method, the concentration distribution can be estimated with probability.

  The above-described method shows a case where an energy spectrum is measured by a pair of gamma ray detectors 2 and energy spectrum measuring device 3, but in order to estimate / evaluate more accurately, gamma ray detection is performed from a plurality of directions. A method of increasing the number of actually measured spectra to be compared by measuring with the instrument 2 and the energy spectrum measuring instrument 3 can be considered. FIG. 5 shows a method for collating and estimating a calculated spectrum and an actually measured spectrum using two gamma ray detectors for measuring energy spectrum in the first embodiment of the method and apparatus for measuring the radioactivity of radioactive waste according to the present invention. It is a system conceptual diagram which shows an example.

  Even when measurement is performed in a plurality of directions, a method of updating and evaluating the above-described weighting factor of each region with a certain step width or a probabilistic method can be applied. Even in the case of the probabilistic method, Expression 2 can be used, and Expression 3 at this time can be expressed as Expression 4.

Here, Sexp1 and Sexp2 represent the actual measured spectra 4 when the energy spectra are measured by the two sets of the gamma ray detector 2 and the energy spectrum measuring device 3, respectively.

  Further, FIG. 6 shows a case where an energy spectrum is measured from a plurality of directions with one set of gamma ray detector 2 and energy spectrum measuring device 3. FIG. 6 shows an example of a method for carrying out measurement in a plurality of directions using a gamma ray detector for measuring one energy spectrum in the first embodiment of the method and apparatus for measuring the activity of radioactive waste according to the present invention. It is a system conceptual diagram which shows. By carrying out such a method, the same effect as in the case of FIG. 5 can be obtained.

  A specific example of the system described with reference to FIGS. 5 and 6 will be described with reference to FIGS. FIG. 7 shows the first embodiment of the radioactive waste body radioactivity measurement method and apparatus according to the present invention, wherein gamma ray detectors for energy spectrum measurement are arranged on each side of the container, respectively, and measurement in a plurality of directions is performed. FIG. 8 is a conceptual diagram showing an example of the configuration of a measurement system that can be used, and FIG. 8 uses the first embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention to measure two energy spectra on each side of the container. It is a conceptual diagram which shows an example of a structure of the measurement system which arrange | positions the gamma ray detector for each, and enables the measurement in multiple directions. 7 and 8, the same reference numerals as those shown in FIGS. 1 to 6 are the same parts, and detailed description thereof is omitted.

  The measurement system shown in FIG. 7 is one in which a gamma ray detector 2 for energy spectrum measurement is installed one by one outside each side surface of the waste container 1, and each side surface is scanned to measure an energy spectrum.

  Specifically, a gamma ray detector scanning device 10 is arranged outside the side surface of the waste container 1. The gamma ray detector scanning device 10 includes a horizontal scanning mechanism 11 that scans the gamma ray detector 2 for energy spectrum measurement in the horizontal direction, a vertical scanning mechanism 12 that similarly scans the gamma ray detector 2 in the vertical direction, and the gamma ray detector 2 vertically. A fixing jig 13 fixed to the direction scanning mechanism 12 and a scanning mechanism control device 14 for controlling the horizontal direction scanning mechanism 11 and the vertical direction scanning mechanism 12 are provided. By using the gamma ray detector scanning device 10 in this manner, the entire surface of each waste container 1 can be measured at a desired measurement interval with a relatively small number of gamma ray detectors 2 for energy spectrum measurement. It becomes possible.

  The gamma ray detector scanning device 10 shown in FIG. 7 includes one horizontal scanning mechanism 11 and one vertical scanning mechanism 12, and one gamma ray detector 2 is provided on each side of the waste container 1. Although it arrange | positions, it is not restricted to this. As shown in FIG. 8, in the case of the gamma ray detector scanning device 10 composed of one horizontal scanning mechanism 11 and two vertical scanning mechanisms 12, two gamma ray detectors 2 are arranged on each side of the waste container 1. can do. Further, the gamma ray detector scanning device 10 may be configured so that a larger number of gamma ray detectors 2 are arranged.

  Next, in the measurement system of the present embodiment, the screen display of the radioactivity amount comparison device 8 when evaluating the radioactivity concentration will be described with reference to FIG. FIG. 9 shows an example of a display screen for displaying the measurement status and estimation / evaluation status on the screen in the measurement system using the radioactive waste body radioactivity measurement method and apparatus according to the first embodiment of the present invention. It is the conceptual diagram shown.

  In the screen display example in FIG. 9, the measured spectrum 4, the calculated spectrum 6 of the divided areas R1, R2,..., The weighting factor of each divided area evaluated in the calculation, and the expression 3 or 4 in the evaluation And a radioactivity concentration estimated and evaluated based on the displayed weighting factor.

  As described above, in order to perform estimation / evaluation by iterative calculation (search), the weighting factor, the square error, the radioactivity concentration, etc. at each iteration stage may be displayed in time series. By setting it as such a display screen, there exists an effect which the validity and explanatoryity of evaluation improve.

  According to the first embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention described above, the radioactive concentration of the radioactive waste housed in the waste body container 1 is stored in the waste body container. Even if there is a radioactive concentration distribution, it can be estimated / evaluated with high accuracy.

  A second embodiment of the radioactive waste body radioactivity measurement method and apparatus according to the present invention will be described below with reference to the drawings. FIG. 10 is a conceptual diagram showing an example of the configuration of a measurement system using the second embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention. In FIG. 10, the same reference numerals as those shown in FIGS. 1 to 9 are the same parts, and detailed description thereof is omitted.

  In the second embodiment of the radioactive waste body radioactivity measurement method and apparatus according to the present invention, the measurement system has a configuration in which the waste container 1 is rotated 90 degrees and the measurement surface is changed as shown in FIG. The difference from the first embodiment is that the gamma ray detector 2 for energy spectrum measurement includes a moving device 20 for scanning and measuring each side surface.

  The moving device 20 mounts the waste container 1 and can move the rotating base 21 that can rotate 360 degrees in the horizontal direction and the rotating base 21 on which the waste container 1 is mounted from one end side to the other end side. And a moving mechanism control device 23 that controls the movement of the rotary base 21 in the moving mechanism 22.

  The scanning device 10 described above is disposed on the other end side of the moving mechanism 22 of the moving device 20. The waste container 1 disposed on the other end side of the moving mechanism 22 by the moving device 20 is scanned by the horizontal scanning mechanism 11, the vertical scanning mechanism 12, and the vertical scanning controlled by the scanning mechanism control device 14 of the scanning device 10. One side of the mechanism 12 is scanned / measured by the gamma ray detector 2 for energy spectrum measurement fixed to the mechanism 12 by a fixing jig 13.

  After the measurement of this one side is completed, the rotary base 21 on which the waste container 1 is placed is moved to one end side thereof by the moving mechanism 22. At this position, the rotary base 21 on which the waste container 1 is placed is rotated 90 degrees in a predetermined rotation direction clockwise or counterclockwise. After that, the moving mechanism 22 moves again to the other end side, and a new one side surface of the waste container 1 is scanned / measured. In this way, all four sides of the waste container 1 are scanned / measured.

  Also, two sets of the radiation scanning device 2 for measuring the energy spectrum fixed to the horizontal scanning mechanism 11, the vertical scanning mechanism 12, and the vertical scanning mechanism 12 by the fixing jig 13 are prepared. It may be arranged in a mold. In this case, the two side surfaces of the waste container 1 can be measured simultaneously, and then the remaining two side surfaces can be measured by rotating the waste container 1 by 180 degrees.

  According to the second embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  Further, according to the second embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention described above, even if there is only one radiation detector 2 for energy spectrum measurement, the waste container 1 Each side can be measured all over, and even if there is a distribution of radioactivity concentration inside the waste container 1, the amount of radioactivity or the radioactivity concentration in the waste container 1 can be accurately estimated and evaluated. .

  Hereinafter, a third embodiment of the radioactive waste body measuring method and apparatus of the present invention will be described with reference to the drawings. FIG. 11 is a system conceptual diagram showing an example of a method for performing measurement on a drum can in the third embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention. In FIG. 11, the same reference numerals as those shown in FIGS. 1 to 10 are the same parts, and detailed description thereof is omitted.

  The radioactive waste body radioactivity measurement method and apparatus according to the third embodiment of the present invention is different from the first embodiment in that the waste container 1 to be measured is a drum can. Others are the same as those in the first and second embodiments.

  Even when the waste container 1 to be measured is in the shape of a drum, basically, the same measurement method as that when the waste container 1 is a square container can be applied. For example, an example of a method for performing measurement in a plurality of directions using one gamma ray detector for energy spectrum measurement according to the first embodiment shown in FIG. 6 is the same measurement method as shown in FIG. Applicable.

  Further, a measurement device in the measurement system, for example, the scanning device 10 or the like can also be measured with an apparatus configuration equivalent to that shown in FIGS. Furthermore, the moving device 20 of the second embodiment can be measured with an apparatus configuration equivalent to that of FIG. Here, when the waste container 1 is rotated, if the rotating pedestal 64 is changed from a square to a circular turntable, translational movement by the moving mechanism 22 becomes unnecessary, and the same measurement can be performed.

  Compared to the conventional radioactivity measurement method performed by rotating a drum can, the radiation measurement method of the present embodiment can accurately consider the influence of the concentration distribution, so the distribution of the radioactivity concentration inside the drum can. Even in some cases, the amount of radioactivity or radioactivity concentration in the container can be accurately estimated and evaluated.

  According to the second embodiment of the radioactive waste body radioactivity measurement method and apparatus of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  Note that the present invention is not limited to the first to third embodiments described above, and includes various modifications. The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace another configuration for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Waste container 1 'Area | region 2 in a waste container 2 Gamma ray detector 3 Energy spectrum measuring device 4 Actual spectrum data 5 Energy spectrum calculation device 6 Calculation spectrum data 7 Database 8 Radioactivity amount comparison device 10 Scanning device 11 Horizontal scanning mechanism 12 Vertical direction scanning mechanism 13 Fixed jig 14 Scanning mechanism control device 20 Moving device 21 Rotating base 22 Moving mechanism 23 Moving mechanism control device

Claims (6)

In the radioactivity measurement method of radioactive waste stored in a storage container,
Radiation energy spectrum analysis for analyzing a radiation energy spectrum by simulating measuring an energy spectrum of radiation leaking from the inside of the storage container outside the storage container in a state where the radioactive waste is stored in the storage container Procedure and
A radiation energy spectrum analysis result storage procedure for storing in a storage device the radiation energy spectrum analysis result analyzed by the energy spectrum analysis procedure;
A radiation energy spectrum measurement procedure for measuring a radiation energy spectrum leaking from the inside of the storage container outside the storage container in a state where the radioactive waste is stored in the storage container;
A radiation energy spectrum reading procedure for reading out the radiation energy spectrum analysis result stored in the storage device by the radiation energy spectrum analysis result storing procedure, if necessary;
The radiation energy spectrum analysis result read out by the radiation energy spectrum readout procedure is referred to, and a difference is derived by comparison with the radiation energy spectrum measurement result measured by the radiation energy spectrum measurement procedure. Based on the derived difference, the radiation energy spectrum is calculated. A search for a spectrum analysis result is repeated, and a radiation energy spectrum search procedure for determining the radiation energy spectrum analysis result having a small difference from the radiation energy spectrum measurement result;
A radioactivity waste radioactivity measurement method comprising: a radioactivity estimation procedure for estimating a radioactivity amount or radioactivity concentration based on the radiation energy spectrum analysis result determined by the radiation energy spectrum search procedure. In the radioactivity measurement method of the radioactive waste body of Claim 1,
The radiation energy spectrum analysis procedure divides the area of the waste body stored in the storage container into a plurality of small areas, and when there is a radiation source in each of the small areas, the outside of the storage container Simulating the measurement of the energy spectrum of radiation leaking from the inside of the storage container, and analyzing the radiation energy spectrum,
The radiation energy spectrum analysis result storage procedure stores each of the radiation energy spectrum analysis results analyzed by the energy spectrum analysis procedure in the storage device,
In the radiation energy spectrum search procedure, when the radiation energy spectrum analysis result is searched, the radiation energy spectrum analysis result is compared with a result obtained by multiplying each of the radiation energy spectrum analysis results by a weighting factor and linearly combining them. A radioactivity measurement method for radioactive waste, characterized by In the radioactivity measurement method of the radioactive waste body of Claim 2,
In the radiation energy spectrum search procedure, when the radiation energy spectrum analysis result is multiplied by a weighting factor and linearly combined, a weighting factor to be multiplied to each of the radiation energy spectrum analysis results is added to the radiation energy spectrum measurement result. A method for measuring the radioactivity of radioactive waste, comprising a procedure for probabilistic or statistical estimation. In the radioactivity measurement apparatus for radioactive waste stored in a storage container,
At least one radiation energy spectrum measuring device for measuring an energy spectrum of radiation leaking from the inside of the storage container outside the storage container in a state where the radioactive waste is stored in the storage container;
A radiation analyzer for simulating the storage container storing the waste and the radiation energy spectrum measuring device and analyzing the energy spectrum of radiation; and
A radiation energy spectrum analysis result storage device for storing an energy spectrum analysis result of radiation leaking from the inside of the storage container, analyzed by the radiation analysis device;
A radiation energy spectrum analysis result reading device that reads out the energy spectrum analysis result of the radiation from the radiation energy spectrum analysis result storage device as necessary;
The radiation energy spectrum analysis result read from the radiation energy spectrum analysis result storage / readout device is referred to, compared with the radiation energy spectrum measurement result measured by the radiation energy spectrum measurement device, and the radiation energy spectrum analysis result and the radiation A radiation energy spectrum search device that repeatedly performs a search for the radiation energy spectrum analysis result based on a difference in the energy spectrum measurement result, and determines a radiation energy spectrum analysis result having a small difference from the radiation energy spectrum measurement result;
Based on the radiation energy spectrum analysis result determined by the radiation energy spectrum search device, comprising a radioactivity estimation device that estimates the radioactivity amount or radioactivity concentration,
A radioactivity measuring apparatus for radioactive waste. In the radioactivity measurement apparatus of the radioactive waste body of Claim 4,
A radioactivity measuring device for radioactive waste, further comprising an estimated value display device for displaying an estimation state or an estimation result of a radioactivity amount or radioactivity concentration by the radioactivity estimation device. In the radioactivity measurement apparatus of the radioactive waste body of Claim 4 or 5,
A radioactivity measurement apparatus for radioactive waste, comprising a plurality of radiation energy spectrum measurement apparatuses.

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