KR102640021B1 - A sampling methods for analysis and evaluation of the over-motor radiological properties of a permanent shutdown nuclear power plant - Google Patents

Abstract

The present invention is a sample collection method for analyzing and evaluating the radiological characteristics of a permanently shut down nuclear power plant in the transient period. The purpose is to analyze and evaluate the radiological characteristics of the transient period for each design space and each system/equipment of the site and structure within the permanently shut down nuclear power plant. The goal is to secure valid samples safely and systematically so that the dismantling task for permanently shut down nuclear power plants can be safely and efficiently completed in the future, and its composition is based on the sample collection method for radiological characteristic analysis during the transition period of permanently shut down nuclear power plants. , the sample collection method collects and analyzes various information on the site, structures, systems, and devices within the permanently shut down nuclear power plant, and based on the analysis results, samples are collected among the sites, structures, systems, and devices within the permanently shut down nuclear power plant. Non-collection targets and destructive sampling exclusion targets by dismantling time are determined, destructive sampling targets by sampling target and dismantling time and execution plan information for sample collection are displayed separately, and are carried out later during sample collection. A sample collection preparatory step of creating a sample collection planning blueprint that reflects the situation and displays, and includes detailed blueprints for each site, structure, system, and device in the permanently shut down nuclear power plant; Confirm the type of each sample collection target based on the sample collection planning design created in the sample collection preliminary preparation stage, inspect the environment and condition of the sample collection target for which the type has been confirmed, and then collect samples for each sample collection target. A sample collection method decision step of determining the method; It is characterized in that it consists of a sample collection step in which sample collection is performed using the sample collection method determined for each sample collection target in the sample collection method determination step.

Description

{A sampling methods for analysis and evaluation of the over-motor radiological properties of a permanent shutdown nuclear power plant}

The present invention relates to a sample collection method for analyzing and evaluating the radiological characteristics of a permanently shut down nuclear power plant in the transient period. More specifically, it analyzes the radiological characteristics of the transient period for each design space and each system/equipment of the site and structure within the permanently shut down nuclear power plant. and sample collection methods for analysis and evaluation of radiological characteristics in the transition period of permanently shut down nuclear power plants, which safely and systematically secure valid samples for evaluation and enable the safe and efficient completion of decommissioning tasks for permanently shut down nuclear power plants to be performed in the future. will be.

Recently, as various nuclear reactors and power generation facilities using them have been newly developed and constructed, it has become necessary to safely dismantle existing old facilities and restore the site.

The final purpose of decommissioning a nuclear facility is to release the decommissioning site and remaining buildings from restrictions under nuclear energy laws and make them usable for other purposes after completing the decommissioning work of the facility.

Therefore, nuclear facilities and sites that have reached the end of their design life need to be decontaminated and dismantled for limited use or free use by the general public.

The site of a nuclear facility where decontamination and dismantlement have been completed must undergo a final open suitability evaluation to determine whether it radiologically satisfies the standards for reuse.

As a standard for the decommissioning site of such nuclear facilities, in Korea, the Nuclear Safety and Security Commission Notice No. 2017-62 (Notice on Radiation Harm Prevention Standards for Intermediate and Low Level Radioactive Waste Disposal Facilities) In order to prevent radiation harm to health and the environment, the performance target of the disposal facility is set at 0.1 mSv (MILLI-SIEVERT) per year as the personal dose limit for a critical group due to normal natural phenomena after closure.

In addition, Nuclear Safety and Security Commission Notice No. 2019-10 (Standard Notice on Radiation Protection, etc.) provides annual validity at the boundary of the restricted area when multiple nuclear-related facilities are operated on the same site to prevent harm caused by nuclear facilities in operation. The dose is specified as 025 mSv.

In overseas cases, the IAEA (INTERNATIONAL ATOMIC ENERGY AGENCY) stipulates that the annual effective dose for individuals in the decision group for unlimited reuse of decommissioned sites should be maintained below 03 mSv through optimization of protection.

On the other hand, in the case of limited reuse, the annual effective dose must not exceed 03 mSv through appropriate restrictions, and even if the restrictions imposed on the decommissioning site are not achieved in the future, the annual effective dose is stipulated not to exceed 1 mSv.

The U.S. NRC (NUCLEAR REGULATORY COMMISSION US) is a radiological standard for unlimited reuse of decommissioned sites. The determined group dose (TEDE) from residual radioactivity does not exceed 025 mSv per year, including from groundwater used for drinking water. It is stipulated that it is suitable for unlimited reuse when the residual radioactivity is minimized by introducing the ALARA (As Low As Reasonably Achievable) concept, and it is stipulated that the permit can be conditionally terminated if certain conditions are met.

In addition, the U.S. EPA (ENVIRONMENTAL PROTECTION AGENCY) sets standards so that the general public will not receive an effective dose exceeding 015 mSv/yr compared to natural radiation dose for 1,000 years after completion of site decommissioning.

[0012] An example of a case of decommissioning and restoration of a nuclear facility is the Fort St Vrain (FSV) nuclear power plant in the United States, which ceased operation and was decommissioned in 1989.

For the unrestricted opening of the decommissioning site, the Fort St Vrain (FSV) nuclear power plant is considering the potential contamination within the site, selection of required measurement and sampling locations, detailed investigation requirements, and comparison of measurement results with applicable regulatory values. Contaminated areas were classified into UNAFFECTED SURVEY UNIT, NON-SUSPECT AFFECTED UNIT, and SUSPECT AFFECTED SURVEY UNIT.

In addition, the classification of each investigation unit is based on data such as the FSV's initial radiological site characteristics report, history or potential contamination with radioactive materials, survey data conducted to perform decommissioning, periodic inspections, accident reports and characterization surveys, etc. and classified them.

In order to establish a plan for on-site radiation measurement and site characterization during decontamination and dismantling, the United States developed a standard procedure called MARSSIM (MULTI-AGENCY RADIATION SURVEY AND SITEINVESTIGATION MANUAL) by integrating various existing radiation measurement and on-site dosimetry standards. It is being used.

When dismantling a nuclear reactor, various nuclides have been detected due to radioactivity caused by neutrons generated during the operation process and trace amounts of impurities present in concrete.

It is necessary to quantify radioactive waste from nuclear power plant decommissioning in order to use it in decommissioning design and decommissioning cost evaluation, or for other purposes. This quantification requires a modeling process, and for this, a database must be prepared.

In other words, since each nuclear fuel that makes up the core has a different composition, each combustion calculation must be performed for all nuclear fuels that make up the core, and the composition corresponding to the combustion state must be applied to construct the core according to the core loading model. In order to automate a series of calculations, basic data must be converted into a database.

In addition, since the extent of radiation in the core outer structures that are radiated by neutrons is different for each area, the vast outer core structures are subdivided into small pieces in the axial and radial directions to calculate the neutron flux and nuclear reaction by location required for radiation calculation. The cross-sectional area must be derived, and since this is a very large task, a process to automatically quantify it is necessary.

However, since there is currently no system that automatically configures the combustion core according to user definitions, when configuring the core, combustion calculations are performed for each nuclear fuel placed in each core region and the combustion state within the core of each assembly is considered. Therefore, a separate program to derive the nuclear fuel composition must be created to construct the core. This makes modeling very time consuming.

In addition, even if the core is completed and the neutron source distribution outside the core can be derived and radiological calculations on the outside of the core can be performed, current technology only allows evaluation of a single area. There is a problem that it requires a very large amount of work time and specialized manpower to quantify the entire outer structure.

In addition, even if the radioactivity level and amount of waste are derived for each area, it takes a considerable amount of time because the waste must be manually sorted one by one.

To solve this problem, Domestic Patent No. 10-0916491, “Evaluation system for nuclear reactor decommissioning waste and its evaluation method,” calculates the nuclide inventory over time by reflecting the decay chain of nuclides present in nuclear reactor decommissioning waste, and decommissioning waste. A technology has been described on how to evaluate decommissioning waste by establishing a database containing data for waste evaluation and quantifying the entire core outer structure rather than a single area.

In addition, in Domestic Patent No. 10-1024039, “Method for dismantling concrete of nuclear reactor shield for research purposes,” samples collected by core boring multiple points of the concrete shield are collected from the center of the core after correcting the density for a certain volume of the source. Methods for measuring the degree of radioactivity depending on the distance to the surface have been described.

However, Domestic Patent No. 10-0916491 only provides a method for evaluating the amount of decommissioning waste, and does not specifically mention a method for evaluating the suitability for opening a decommissioning site through the amount of waste.

In addition, Domestic Patent No. 10-1024039 requires a process of drilling and analyzing samples through core boring at the dismantlement site and then evaluating the depth of contamination to gradually remove the contaminated soil. This process The investigation period was prolonged due to the distribution of continuous contamination, resulting in a significant waste of time and cost.

Therefore, among the element technologies to ensure decommissioning-related safety when decommissioning a permanently shut down nuclear power plant, there is an urgent need to develop a radiological characteristic survey system that can confirm site residual radioactivity and technologies related to standard safety evaluation related to decommissioning, and these related technologies are urgently needed. In order to promote development, it is time to proactively develop radiological sampling technology for the permanent shutdown of nuclear power plants, which is the basis for radiological characteristic investigation systems and standard safety assessments related to decommissioning.

The present invention was developed in consideration of the above-described conventional problems, and its purpose is to provide effective samples for analysis and evaluation of transient radiological characteristics for each design space of the site and structure and each system/equipment within a permanently shut down nuclear power plant. It provides a sample collection method for analysis and evaluation of radiological characteristics in the transition period of a permanently shut down nuclear power plant, which can safely and systematically secure and safely and efficiently complete the decommissioning task for the permanently shut down nuclear power plant to be performed in the future.

The object of the present invention is to provide a sample collection method for analyzing radiological characteristics during the transition period of a permanently shut down nuclear power plant. The sample collection method collects and analyzes various information on the site, structures, systems and devices within a permanently shut down nuclear power plant, and analyzes them. Based on the results, among the sites, structures, systems, and devices within the permanently shut down nuclear power plant, the subjects subject to sampling, non-objects of sampling, and subjects excluded from destructive sampling by dismantling time are determined. Execution plan information for sample collection is displayed separately, progress is reflected and displayed during future sample collection, and detailed design drawings for each site, structure, system, and device within a permanently shut down nuclear power plant are attached. A preliminary preparation step for sample collection to produce a planning blueprint; Confirm the type of each sample collection target based on the sample collection planning design created in the sample collection preliminary preparation stage, inspect the environment and condition of the sample collection target for which the type has been confirmed, and then collect samples for each sample collection target. A sample collection method decision step of determining the method; A sample collection method for analysis and evaluation of radiological characteristics in the transition period of a permanently shut down nuclear power plant, characterized in that it consists of a sample collection step of conducting sample collection using the sample collection method determined for each sample collection target in the sample collection method decision step. This can be achieved by

According to the sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant according to the present invention, the unit area for each design space, system, and device of the site and structure within the permanently shut down nuclear power plant is preset, and each unit area is set. By safely and systematically securing samples that are radiologically representative, we lay the foundation for the development of standardization technology for radiological characteristic evaluation during the transition period of permanently shut down nuclear power plants, while at the same time making it safe and efficient to dismantle the permanently shut down nuclear power plants that will be performed in the future. By allowing this to be done, it has the effect of reducing the time and cost required to dismantle a permanently shut down nuclear power plant.

Figure 1 is a block diagram illustrating the configuration of a sample collection method for analysis and evaluation of radiological characteristics in the transient phase of a permanently shut down nuclear power plant according to the present invention;
Figure 2 is a flowchart illustrating the configuration of the sample collection preliminary preparation stage among the sample collection method for analyzing and evaluating radiological characteristics in the transient phase of a permanently shut down nuclear power plant according to the present invention illustrated in Figure 1,
FIG. 3 is a flowchart illustrating the configuration of the sample collection target decision step among the sample collection preparatory steps illustrated in FIG. 2;
Figure 4 is a flow chart illustrating another embodiment of the sample collection preliminary preparation step illustrated in Figure 2,
Figures 5 and 6 are schematic descriptions of the state of conducting preliminary radiation (activity) measurements on sites, structures, and the inside of structures within a permanent site using radiation (ability) detection means (drones and UGVs). It's a degree.
all.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. The present embodiments are merely provided to ensure that the disclosure of the present invention is complete, and that the present invention is known to those skilled in the art. It is provided to fully inform those who have the invention and scope, and is limited by the claims of the present invention.

In describing embodiments of the present invention, if it is determined that detailed descriptions of already known functions or configurations may unnecessarily obscure the gist of the present invention, the detailed descriptions will be omitted. In addition, the terms described below are terms defined in consideration of functions in embodiments of the present invention, and may vary depending on the intention or custom of the user or operator. Therefore, the definition should be made based on the contents throughout this specification.

The present invention safely and systematically collects radiological samples representative of the transition period of a permanently shut down nuclear power plant, thereby laying the foundation for the development of standardization technology for evaluating the radiological characteristics of a permanently shut down nuclear power plant, while also providing for the decommissioning task for permanently shut down nuclear power plants to be performed in the future. This relates to sample collection methods for analysis and evaluation of radiological characteristics during the transition period of permanently shutting down nuclear power plants, which are necessary to ensure safe and efficient completion.

In order to develop a highly complete technology for the standardization of radiological characteristics evaluation during the transition period of permanently shut down nuclear power plants and to complete the decommissioning task for permanently shut down nuclear power plants to be carried out in the future, waste disposal plans, public acceptance, and restoration of waste generated during the decommissioning process of permanently shut down nuclear power plants are to be completed. A restoration strategy must be established considering the required budget, schedule, and regulatory requirements.

The residual contamination must be reduced to a radiologically acceptable level by removing contaminants quickly and efficiently so that the residual contamination level, which is the final goal of the decommissioning task for these permanently shut down nuclear power plants, is lower than the open suitability standard.

For this purpose, in the present invention, various information on sites, structures, systems, and devices within permanently shut down nuclear power plants are collected and analyzed, and based on the analysis results, sampling targets and sample collection among sites, structures, systems, and devices within permanently shut down nuclear power plants are selected. Determine the subjects excluded from destructive sampling by non-object and dismantlement time, distinguish destructive sampling targets and sampling execution plan information by sampling target and dismantling time, and determine the type of each sampling subject based on this. After checking the environment and condition of the sample collection target whose type has been confirmed, the sampling method for each sample collection target is determined, and sample collection is conducted using the sampling method determined for each sample collection target. Provides a sample collection method for analysis and evaluation of radiological characteristics during the transition period of a nuclear power plant at a standstill.

Hereinafter, with reference to the attached drawings FIGS. 1 to 6, a preferred embodiment of the sample collection method for analyzing and evaluating radiological characteristics of a permanently shut down nuclear power plant transition period according to the present invention will be described in detail.

Referring to Figure 1, the sample collection method for analysis and evaluation of radiological characteristics during the transition period of permanently shut down nuclear power plant according to the present invention includes a sample collection preparatory step (S100), a sample collection method determination step (S200), and a sample collection step ( S300).

Referring to Figures 1 and 2, the sample collection preliminary preparation step (S100) collects and analyzes various information on the site, structure, system, and equipment within the permanently shut down nuclear power plant, and based on the analysis results, Among sites, structures, systems, and devices, determine sampling targets, non-sampling targets, and destructive sampling exclusions by dismantling time, and provide destructive sampling targets and sample collection action plan information by sampling target and dismantling time. A preparatory stage to produce a sampling planning blueprint, which is displayed separately, reflects the progress during future sampling, and includes detailed blueprints for each site, structure, system, and device within the permanently shut down nuclear power plant. It consists of a sample collection plan production step (S110), a sample collection target decision step (S120), and a sample collection point selection step (S130).

The sample collection planning design production step (S110) produces an integrated design drawing that integrates the design drawings of the site, structure, system, and equipment within the permanently shut down nuclear power plant, and uses a grid on the produced integrated design drawing to determine a preset unit area. Create a sample collection planning design by dividing it into sections.

Referring to Figures 1 and 3, the sample collection target determination step (S120) analyzes the design documents and site history survey of the site, structure, system, and equipment within the permanently shut down nuclear power plant, and determines the permanently shut down nuclear power plant based on the analysis results. For each unit area of the site, structure, system, and equipment, it is determined that each unit area is subject to sampling, not subject to sampling, or excluded from destructive sampling by time of dismantling, and based on that decision, the sample collection planning blueprint and the attached detailed design drawing are consulted. This is the step of displaying the decision result for each corresponding unit area, and it consists of a unit area type confirmation step (S121), a site sampling target decision step (S122), a structure sample collection target decision step (S123), It consists of a determining step for sampling targets for systems and devices (S124) and a determining step for destructive sampling targets by dismantling time (S125).

The unit area type confirmation step (S121) confirms whether the unit area falls under any one of the following exclusions from sampling by site, structure, system and equipment, and dismantling time.

In the unit area type confirmation step (S121), if the type of unit area is site, review the site history survey, underground piping-related drawings, engineering design information, radioactive waste storage area, and radioactive waste transfer route. Therefore, the unit area where pipes and devices containing radioactive fluid are located is determined as the sample collection target.

In addition, the sampling target determination step (S122) for the site is a unit area for additional sampling with respect to the surrounding unit area of the sampling target unit area corresponding to the most dominant (highest occurrence frequency) wind direction around the permanently shut down nuclear power plant. can be decided.

The sample collection target decision step (S123) for the structure is determined in the unit area type confirmation step (S121). If the type of the unit area is a structure, the unit area is determined by site history, design characteristics, and engineering judgment. Considering this, the unit area expected to have a high possibility of contamination is determined as the target for sampling.

In addition, in the determination step (S123) of the structure's sample collection target, if the structure is a building, the unit area is the compartments and areas of the building, and ① among the compartments and areas within the building, it is classified as a radiation management area and includes radioactive devices. ② A place that does not contain radioactive equipment, but is located within a radiation control area and has a high possibility of cross-contamination, so a place where the possibility of radioactive contamination due to physical location has been confirmed; ③ A place that is not classified as a radiation control area However, there is a high possibility that significant contamination, including potential radioactive devices, will be discovered, so sample collection targets are determined in places where potential radioactive contamination has been confirmed, and ④ places that are radiologically and physically accessible and have confirmed accessibility.

The sample collection target determination step for the system and device (S124) is determined in the unit area type confirmation step (S121). If the type of the unit area is a system or device, the pressure and flow of the radioactive fluid are determined. The sample collection target is determined for one or more of the following: the location is located, the distance from the radioactive contamination source is close, or there is a filter and desalination device.

In addition, the sample collection target determination step (S124) of the above-mentioned systems and devices is ① a location that directly contains radioactive fluid and has been confirmed as a radioactive system, ② a location that is in direct contact with the system and device containing radioactive fluid and has been identified as a potential radioactive system. ③ A location with similar contamination characteristics is selected as the target for sample collection.

The destructive sampling target determination step (S125) is determined in the unit area type confirmation step (S121). If the type of unit area is excluded from destructive sampling by dismantling time, the unit area is selected at the dismantling time. Each item is excluded from destructive sampling.

The subjects excluded from sample collection by the above dismantlement time include ① the reactor cooling system, ② the chemical and volume control system, ③ the residual heat removal system, and the intrinsic safety function system in the permanently shut down nuclear power plant, which are the system decontamination target and related systems in the permanently shut down nuclear power plant. Spent nuclear fuel storage tank cooling and purification system ② Essential equipment cooling system and normal operating function system in a permanently shut down nuclear power plant ① Boron recovery system ② Liquid/gas/solid waste system ③ Radiation monitoring system ④ Exhaust system for each building ⑤ Pump actual circulation system ⑥ Including the power plant drainage system, destructive sampling of each sampling exclusion object at the time of dismantling is performed after each sampling exclusion object has terminated its own or normal operation function.

Referring to Figures 1 and 2, the sample collection point selection step (S130) selects a sample collection point for each unit area determined as the sample collection target in the sample collection target determination step (S120). In other words, in the case of a structure within a permanently shut down nuclear power plant, ① a point with a high possibility of contamination, ② if it is difficult to select a point, a randomly selected point on the floor or a wall less than 2m from the floor, ③ a point where the radioactivity concentration in the air is expected to be high. Select a randomly selected point on the wall and ceiling surface 2m or more from the floor of the expected compartment or area as the sampling point.

Referring to FIG. 1, the sample collection method determination step (S200) confirms the type of each sample collection target based on the sample collection planning design created in the sample collection preliminary preparation step (S100), and samples of which the type has been confirmed After inspecting the environment and condition of the collection target, the sampling method for each sample collection target is determined. In other words, the sampling method determination step (S200) determines the sampling method according to the type of unit area subject to sampling, and when the unit area subject to sampling is a site and a concrete structure, samples of the ground and underground or floor surfaces, The drilling method that collects samples from the ceiling, the surface of the wall, and the deep part at once is determined as the sampling method. If the unit area subject to sampling is a system and device, the sample is collected by cutting the system and device to a certain size. If the cutting method is determined as the sampling method, the unit area subject to sampling is a compartment or zone of a building, and air samples within the compartment or zone are to be collected, the intake collection method is determined as the sampling method, and the unit area subject to sampling is determined as the sampling method. If it is a structure where liquid accumulates within the area, such as a water sump, and you want to collect liquid samples within the structure, the sampling method is determined as the sampling method.

In the above water sampling method, when the water depth is more than 1 m, liquid samples are collected for surface water, middle water, and deep water, respectively. When the water depth is less than 1 m, liquid samples are collected after stirring the water to be collected.

In the sample collection step (S300), sample collection is performed using the sample collection method determined for each sample collection target in the sample collection method determination step (S200).

Additionally, referring to FIG. 4, the sample collection preliminary preparation step (S100) may further include a preliminary radiation (activity) measurement step (S140).

In the preliminary radiation (capacity) measurement step (S140), after the sample collection plan production step is completed, radiation (capacity) measurement for each unit area of the site and structure within the permanently shut down nuclear power plant is performed based on the completed sample collection plan blueprint. Roughly speaking, it is carried out using radiation detection means.

When the preliminary radiation (activity) measurement step (S140) is included in the sample collection preliminary preparation step (S100), the sample collection target decision step (S120) includes the design documents and site of the site, structure, system, and equipment within the permanently shut down nuclear power plant. By referring to the radiation (capacity) measurement data for each unit area obtained through the preliminary radiation (capacity) measurement step above along with the analysis results of the history survey, sample collection targets and samples are collected for each unit area of the site and structure within the permanently shut down nuclear power plant. It is determined as either non-collection or exclusion from destructive sampling at the time of dismantlement.

As the radiation detection means, a portable radiation detector, a remote control drone, and a remote control unmanned ground vehicle (UGV) can be optionally used.

The portable radiation detector is a typical portable radiation detector, which is relatively inexpensive to purchase, and can be easily carried by workers while moving around to provide radiation (radiation) to sites, structures, systems, and devices within a permanently shut down nuclear power plant. There is an advantage in being able to measure radiation (activity) on a site with a large area, but it requires a long time and involves labor, as well as the risk of safety accidents in areas with high radiation (activity). The disadvantage is that access to the outer surface of tall structures is limited.

Referring to FIG. 5, the remote control drone has a radiation (capability) detection unit that measures radiation (capability) and transmits the measurement signal, measures the distance by irradiating a distance measurement laser, and transmits the measurement signal. one or more laser distance measurement units, one or more camera units that photograph the surrounding situation and transmit the acquired images, and are respectively connected to the radiation (ability) detection unit, the laser distance measurement unit, and the camera unit, and each unit It is equipped with a data communication module that transmits the data received from the control panel, and its operation is remotely controlled by the control panel, so that it can quickly measure radiation (activity) on the outer surface of the site and structure within a permanently shut down nuclear power plant while flying at a set altitude and speed. It has the advantage of being able to be carried out easily, but it has the disadvantage of not being able to measure radiation (activity) on the inside of the structure because it is an aircraft, and that the availability of equipment is relatively high.

Referring to FIG. 6, the remotely controlled unmanned ground vehicle (UGV) measures the distance by irradiating a radiation (capability) detection unit that measures radiation (capacity) and transmits the measurement signal, and a distance measurement laser. and one or more laser distance measurement units that transmit the measurement signal, one or more camera units that photograph the surrounding situation and transmit the acquired images, the radiation (ability) detection unit, the laser distance measurement unit, and the camera unit, respectively. It is connected and equipped with a data communication module that transmits the data received from each unit, and its operation is controlled remotely by the control panel, so it moves around the inside of the structure in the permanently shut down nuclear power plant and covers each unit area (format and area). It can be useful for radiation (capacity) measurement, especially in restricted areas with high radiation (capacity), but it can also measure radiation (capacity) on the external surface of a structure, and the purchase cost is low. There is a downside to being tall.

The sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant according to the present invention having the above configuration includes a sample collection preliminary preparation step (S100), a sample collection method determination step (S200), and a sample collection step ( S300) to safely and systematically secure valid samples to analyze and evaluate the transient radiological characteristics of each design space and each system/equipment of the site and structure within the permanently shut down nuclear power plant. It has the advantage of allowing dismantling tasks to be completed safely and efficiently.

As such, a person skilled in the art will understand that the technical configuration of the present invention described above can be implemented in other specific forms without changing the technical idea or essential features of the present invention.

Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive, and the scope of the present invention is indicated by the claims described later rather than the detailed description above, and the meaning and scope of the claims and their equivalents. All changes or modified forms derived from the concept should be construed as falling within the scope of the present invention.

S100: Preparation stage for sample collection
S110: Sample collection planning blueprint production stage
S120: Sample collection target decision step
S121: Unit area type confirmation step
S122: Site sampling target decision step
S123: Sampling target decision step for the structure
S124: Determination of sampling targets for systems and devices
S125: Destructive sampling target decision stage by dismantling time
S130: Sample collection point selection step
S140: Preliminary radiation (activity) measurement step
S200: Sample collection method decision step
S300: Sample collection step

Claims (14)

In the sample collection method for radiological characteristic analysis during the transition period of permanently shut down nuclear power plants,
The sample collection method is,
Collect and analyze various information on sites, structures, systems, and devices within a permanently shut down nuclear power plant, and based on the analysis results, determine sample collection targets, non-sample collection targets, and dismantling points among the sites, structures, systems, and devices within a permanently shut down nuclear power plant. The subjects excluded from destructive sampling are determined, and the destructive sampling targets and sample collection expulsion plan information are displayed separately by sampling target and dismantlement time, and the progress is reflected and displayed when sampling is carried out in the future. , a sample collection preparatory step (S100) of producing a sample collection planning blueprint attached with detailed blueprints for each site, structure, system, and device within a permanently shut down nuclear power plant;
The type of each sample collection target is confirmed based on the sample collection planning design created in the sample collection preliminary preparation step (S100), and the environment and condition of the sample collection target for which the type has been confirmed are inspected, and then each sample collection target is inspected. A sample collection method determination step (S200) of determining a sample collection method for the sample;
Analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that it consists of a sample collection step (S300) in which samples are collected using the sample collection method determined for each sample collection target in the sample collection method decision step (S200). Sample collection method for.
According to paragraph 1,
In the sample collection preliminary preparation step (S100),
An integrated design drawing that integrates the design of the site, structure, system, and equipment within a permanently shut down nuclear power plant is produced, and a sample collection planning design is created by dividing the produced integrated design into a preset unit area using a grid. Collection planning blueprint production step (S110);
Analyze design documents and site history surveys of sites, structures, systems, and devices within permanently shut down nuclear power plants, and based on the analysis results, sample collection targets and samples for each unit area of sites, structures, systems, and devices at permanently shut down nuclear power plants. A sampling target determination step (S120) in which the decision is made to be one of the non-collection targets or the destructive sampling exclusion targets at the time of dismantling, and the decision results are displayed in each corresponding unit area on the sample collection planning blueprint and the attached detailed blueprint according to the decision; ;
Analysis of radiological characteristics during the transition period of a permanent shutdown nuclear power plant, characterized in that it consists of a sampling point selection step (S130) of selecting a sample collection point for each unit area determined as a sample collection target in the sample collection target determination step (S120), and Sample collection method for evaluation.
According to paragraph 2,
The sample collection target determination step (S120) is,
A unit area type confirmation step (S121) to check whether the unit area falls under any one of the following: site, structure, system and equipment, and sample collection exclusion by dismantling time;
In the unit area type confirmation step (S121), if the type of unit area is a site, review the site history survey, underground piping-related drawings, engineering design information, radioactive waste storage area, and radioactive waste transfer route. A sampling target determination step (S122) for determining a sample collection target for a unit area where piping and equipment containing radioactive fluid are located;
In the unit area type confirmation step (S121), if the type of unit area is a structure, the unit area is expected to have a high possibility of contamination considering site history, design characteristics, and engineering judgment. With respect to the sample collection target determination step (S123) of the structure determined as the sample collection target;
In the unit area type confirmation step (S121), if the type of unit area is a system or device, it is a location where there is pressure and flow of radioactive fluid, or the distance from the source of radioactive contamination is close, or A sample collection target determination step (S124) for determining the sample collection target for a unit area corresponding to one or more of the cases where there is a filter and a desalinator;
In the unit area type confirmation step (S121), if the type of unit area is excluded from destructive sampling by dismantling time, the destructive sample by dismantling time is determined to exclude the unit area from destructive sampling by dismantling time. A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that it consists of a collection target determination step (S125).
According to paragraph 3,
Those excluded from sample collection by the above dismantling time are:
The systems and related systems subject to system decontamination in permanently shut down nuclear power plants are: ① reactor cooling system, ② chemical and volume control system, ③ residual heat removal system;
Inherent safety function systems in permanently shut down nuclear power plants include: ① spent nuclear fuel storage tank cooling and purification system, ② essential equipment cooling system;
Normal operation function systems in permanently shut down nuclear power plants include ① boron recovery system, ② liquid/gas/solid waste system, ③ radiation monitoring system, ④ building-specific exhaust system, ⑤ pump room circulation system, and ⑥ power plant drainage system;
The subjects excluded from sampling by the time of dismantlement are the transient radiation of a permanent shutdown nuclear power plant, characterized in that destructive sampling is performed on each subject excluded from sampling at a time after the end of each unique or normal operation function. Sample collection method for analysis and evaluation of academic characteristics.
According to paragraph 3,
The determination step (S122) for sampling the site is,
Transient radiological characteristics of a permanently shut down nuclear power plant, characterized in that the unit area subject to additional sampling is determined with respect to the unit area surrounding the unit area subject to sampling corresponding to the most dominant (highest occurrence frequency) wind direction around the permanently shut down nuclear power plant. Sample collection method for analysis and evaluation.
According to paragraph 3,
The determination step (S123) for sampling the structure is,
If the structure is a building, the compartments and areas of the building are considered the unit area;
① Among the compartments and areas within the building, they are classified as radiation control areas and contain radioactive equipment, so a high possibility of radioactive contamination has been confirmed. ② They do not contain radioactive equipment, but are located within a radiation control area, so there is a high possibility of cross-contamination. Places where the possibility of radioactive contamination has been confirmed based on location, ③ Areas that are not classified as radiation control areas, but where the possibility of potential radioactive contamination has been confirmed due to the high possibility of significant contamination including potential radioactive devices, ④ Radiologically and physically A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that an area where accessibility has been confirmed is selected as the sample collection target.
According to paragraph 3,
The determination step (S124) of sampling targets for the systems and devices is,
① Places that directly contain radioactive fluid and have been confirmed to be radioactive systems, ② Places that are in direct contact with systems and devices containing radioactive fluids and have been identified as potential radioactive systems, ③ Places that have similar contamination characteristics and thus are subject to sample collection. A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that determination.
According to paragraph 2,
In the sample collection point selection step (S130),
In the case of a structure within a permanently shut down nuclear power plant,
① A point with a high possibility of contamination, ② When it is difficult to select a point, a randomly selected point on the floor or a wall less than 2m from the floor, ③ 2m from the floor of a compartment or area where the concentration of radioactivity in the air is expected to be high. A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that randomly selected points on the walls and ceiling above are selected as sample collection points.
According to paragraph 1,
In the sample collection method determination step (S200),
The sampling method is determined depending on the type of unit area to be sampled;
If the unit area subject to sampling is a site or concrete structure, a drilling method that collects samples of the ground and underground or the surface and deep portion of the floor, ceiling, and wall at once is determined as the sampling method;
If the unit area subject to sample collection is a system and device, the cutting method of collecting the sample by cutting the system and device to a certain size is determined as the sampling method;
If the unit area subject to sampling is a compartment or zone of a building, and it is desired to collect air samples within the compartment or zone, the intake air collection method is determined as the sampling method;
For the analysis and evaluation of radiological characteristics during the transition period of permanently shut down nuclear power plants, where the sample collection target unit area is a structure in which liquid is accumulated, such as a sump, and a liquid sample within the structure is to be collected, the sampling method is determined. Sample collection method.
According to clause 9,
The above water collection method is,
If the water depth is more than 1m, liquid samples are collected for surface water, middle water, and deep water, respectively.
When the water depth is less than 1 m, a sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that liquid samples are collected after stirring the water to be collected.
According to paragraph 2,
The sample collection preliminary preparation step (S100) is,
After the sample collection plan production stage is completed, radiation (capacity) measurements for each unit area of the site and structure within the permanently shut down nuclear power plant are roughly performed using radiation (capacity) detection means based on the completed sample collection plan blueprint. It further includes a preliminary radiation (ability) measurement step (S140);
The sample collection target decision step (S120) is,
Permanent shutdown by referring to the radiation (capacity) measurement data for each unit area obtained through the preliminary radiation (capacity) measurement step above, along with the analysis results of the design documents and site history survey of the site, structure, system, and equipment within the nuclear power plant. Sample collection for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that each unit area of the site and structure within the nuclear power plant is determined as one of the subjects of sampling, non-sampling, or exclusion of destructive sampling by time of dismantlement. method.
According to clause 11,
The radiation (activity) detection means is,
It is a portable radiation (capacity) detector, carried by the worker, and measures radiation (capacity) for the site, structure, system, and equipment within the permanently shut down nuclear power plant. It is characterized by analyzing radiological characteristics of the permanently shut down nuclear power plant transition period and Sample collection method for evaluation.
According to clause 11,
The radiation (activity) detection means is,
A radiation (capacity) detection unit that measures radiation (capacity) and transmits the measurement signal, one or more laser distance measurement units that irradiate a distance measurement laser to measure the distance and transmit the measurement signal, and photograph the surrounding situation. , one or more camera units that transmit the acquired images, and a data communication module that is connected to the radiation (capacity) detection unit, the laser distance measurement unit, and the camera unit, and transmits the data received from each unit, It is a remote controlled drone whose operation is controlled remotely by a control panel;
A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that it measures the radiation (capacity) on the outer surface of the site and structure within the permanently shut down nuclear power plant while flying at a set altitude and speed.
According to clause 11,
The radiation (activity) detection means is,
A radiation (capacity) detection unit that measures radiation (capacity) and transmits the measurement signal, one or more laser distance measurement units that irradiate a distance measurement laser to measure the distance and transmit the measurement signal, and photograph the surrounding situation. , one or more camera units that transmit the acquired images, and a data communication module that is connected to the radiation (capacity) detection unit, the laser distance measurement unit, and the camera unit, and transmits the data received from each unit, It is a remotely controlled unmanned ground vehicle (UGV) whose operation is controlled remotely by a control panel;
A sample collection method for analysis and evaluation of radiological characteristics during the transition period of a permanently shut down nuclear power plant, characterized in that the radiation (capacity) for each unit area (format and zone) is measured while moving inside the structure within the permanently shut down nuclear power plant.

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