Radioactive waste maritime transport radiation risk assessment system and method

Abstract

A radiation risk assessment system for the maritime transport of radioactive waste is provided. The system comprises a service server that stores data regarding the maritime transport of radioactive waste and performs radiation risk assessment and calculation, and a user terminal that receives risk assessment results by inputting transport information, vessel information, and transport route information. The service server comprises a database that stores and manages data necessary for the radiation risk assessment of the maritime transport of radioactive waste, a risk assessment unit that performs risk assessments classified by exposure target, a risk calculation unit that calculates physical factors necessary for the risk assessment, and a result providing unit that processes the calculation results of the risk assessment unit and the risk calculation unit and provides them to the user terminal. The risk includes at least one of the exposure dose received by the exposure target, the expected dose reflecting the probability of an accident, and the limit utilization rate, which is the ratio of the exposure dose to the regulatory limit.

Description

Technology Field

[0001] The present invention relates to a system and method for evaluating radiation risk during the maritime transport of radioactive waste, and more specifically, to a system and method for comprehensively evaluating radiation risk by calculating external exposure dose rates, internal exposure dose rates, atmospheric dispersion factors, deposition factors, and risk spatial grids for the general public, ship crew members, and cargo handling workers near the departure and arrival points, as well as the general public near the ocean in the event of an accident, for each of the normal operation conditions and accident conditions during the maritime transport of radioactive waste. Background Technology

[0003] Radioactive waste is generated through various channels, such as the operation of nuclear power plants, nuclear fuel reprocessing, and the use of radioactive materials in the medical and industrial sectors; this waste must be transported from its point of origin to interim storage facilities or permanent disposal facilities. Means of transport for radioactive waste include land transport (roads, railways), maritime transport (ships), and air transport. Among these, maritime transport is utilized for routes connecting nuclear facilities on islands or overseas reprocessing facilities due to its advantage of being able to move large quantities of radioactive waste relatively economically.

[0004] During the maritime transport of radioactive waste, exposure to radiation emitted from the transport may occur, which is classified into exposure under normal operating conditions and exposure under accident conditions. Under normal operating conditions, external exposure caused by gamma rays and neutron rays emitted from the outer surface of the transport is the primary concern, while under accident conditions, both external and internal exposure must be considered, which may occur when radioactive material leaks out due to damage to the transport's shielding structure caused by a collision or sinking of the vessel.

[0005] In this regard, conventional radiation risk assessments for radioactive waste transportation have primarily been developed for land transport, and dedicated assessment systems reflecting the specific characteristics of maritime transport have been lacking. Applying land transport risk assessment methodologies directly to maritime transport presented limitations, as they failed to adequately reflect variables unique to maritime transport, such as marine weather conditions, vessel movement paths, duration of stay at anchorages, types of maritime accidents (collisions, sinking, etc.) and accident rates, and the diffusion patterns of radioactive materials caused by ocean currents. Furthermore, there was a absence of a system that systematically integrated assessment criteria specific to maritime accidents, such as calculating atmospheric diffusion factors to predict the diffusion paths of radioactive materials released into the atmosphere in the event of an accident, or calculating deposition factors to evaluate exposure caused by radioactive materials deposited on the surface. Prior art literature

[0007] Korean Patent Publication No. 10-2009-0049310, published on May 18, 2009 The problem to be solved

[0008] The problem that the present invention aims to solve is to provide a system and method capable of systematically evaluating radiation risk by encompassing both normal operating conditions and accident conditions during the maritime transportation of radioactive waste.

[0009] In addition, another objective of the present invention is to provide a system capable of performing risk assessments classified by exposure targets, such as the general public around the transport origin and destination, ship crew members along the transport route, workers handling the transported goods, and the general public near the ocean in the event of an accident.

[0010] In addition, another objective of the present invention is to provide a system that quantitatively provides the radiation risk of maritime transport by integrally calculating various radiation risk calculation factors, such as external exposure dose rate, internal exposure dose rate, atmospheric diffusion factor, deposition factor, and risk spatial grid.

[0011] The problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0013] A radiation risk assessment system for the maritime transport of radioactive waste according to one embodiment for solving the above problem comprises a service server that stores data regarding the maritime transport of radioactive waste and performs radiation risk assessment and calculation, and a user terminal that receives risk assessment results by inputting transport information, vessel information, and transport route information. The service server comprises a database that stores and manages data necessary for the radiation risk assessment of the maritime transport of radioactive waste, a risk assessment unit that performs risk assessments classified by exposure target, a risk calculation unit that calculates physical factors necessary for the risk assessment, and a result providing unit that processes the calculation results of the risk assessment unit and the risk calculation unit and provides them to the user terminal. The risk includes at least one of the exposure dose received by the exposure target, the expected dose reflecting the probability of an accident, and the limit utilization rate, which is the ratio of the exposure dose to the regulatory limit.

[0014] The above database comprises: cargo data including cargo type, external dimensions, weight, maximum external surface dose rate, transport index (TI), radioactivity, shielding structure and material; radionuclide data including radionuclide name, half-life, radioactivity, type and energy of radiation, radiation weighting factor, dose conversion factor, and internal exposure dose factor due to inhalation and ingestion; ship data including ship name, gross tonnage (GT), deadweight tonnage (DWT), maximum speed, cargo hold structure, cargo loading location, number of crew, and distance between crew duty location and cargo loading location; transport route data including coordinates of departure port, arrival port, and transit port, voyage distance and duration per segment, anchorage location and anchorage time, collision and sinking accident rates per segment, and population density around departure point, arrival point, and anchorage; and wind direction, wind speed, temperature, humidity, Pasquill-Gifford atmospheric stability classification, precipitation amount, precipitation type, sea level pressure, and It can store meteorological data including the direction and speed of ocean currents, and accident scenario data including the type of accident, accident severity grade, degree of cargo damage, release fraction, release pattern, accident rate, and duration of radioactive material release.

[0015] The above risk assessment unit may include a general public assessment module for assessing radiation risk to general public residing or working near the port of origin and destination of the transport, a transport route vessel crew assessment module for assessing radiation risk to crew members aboard the maritime transport vessel, a transport handling worker assessment module for assessing radiation risk to workers directly handling radioactive waste transport, and a general public assessment module for assessing radiation risk to general public near the accident area when radioactive material is released in the event of an accident during maritime transport.

[0016] The above-mentioned risk calculation unit may include an external exposure dose rate calculation module that calculates the dose rate when the carrier shielding structure is intact under normal operating conditions and the dose rate when the carrier shielding structure is damaged under accident conditions, respectively; an internal exposure dose rate calculation module that calculates the internal exposure dose rate when radioactive material released from the carrier under accident conditions enters the human body through inhalation or ingestion; an atmospheric diffusion factor calculation module that calculates an atmospheric diffusion factor indicating the degree of diffusion of radioactive material released into the atmosphere under accident conditions according to weather conditions; a deposition factor calculation module that calculates the surface contamination concentration due to dry deposition and wet deposition of radioactive material diffused into the atmosphere; and a risk spatial grid calculation module that generates a spatial grid by dividing the maritime transport route and surrounding area into a predetermined size and assigns an accident occurrence rate to each grid cell.

[0017] The result providing unit refers to the annual scheduled number of transports (N) stored in the transport route data, calculates the annual cumulative exposure dose for each exposure target by multiplying the single-time port-area general public exposure dose calculated by the general public evaluation module around the transport origin / destination, the single-time ship crew cumulative exposure dose calculated by the transport route ship crew evaluation module, and the single-time handling worker exposure dose calculated by the transport handling worker evaluation module by the annual number of transports (N) for each, calculates the limit utilization rate for each exposure target by comparing the calculated annual cumulative exposure dose with the International Commission on Radiological Protection (ICRP) annual dose limit for the general public and domestic regulatory standards, and provides a message to the user terminal recommending a review of safety improvement measures such as reducing the number of transports, changing the transport route, or strengthening shielding if the limit utilization rate is above a preset ratio, and automatically calculates the smallest value among the values ​​obtained by dividing each exposure target's annual dose limit (D_limit) by the single-time exposure dose (D_single) as the maximum allowable annual number of transports and provides this to the user terminal. It is possible.

[0018] The above risk spatial grid calculation module receives real-time location information of a transport vessel from an AIS (Automatic Identification System) through the communication unit, converts the received location information into a grid coordinate system to update the risk spatial grid at a predetermined period, and when it is detected that the vessel has deviated from a pre-set transport plan route by more than a pre-set reference distance, it automatically generates a new grid range corresponding to the deviation route, queries and updates sea area characteristic data to be applied to the grid from the transport route data, and if the risk level based on the recalculated current location rises by more than a pre-set ratio of the pre-evaluation value, it issues an automatic alarm including the current vessel location coordinates, the risk increase rate, and the cause of the risk increase to the user terminal through the result providing unit, and derives and provides an alternative grid route in which the risk level is less than 100% of the pre-evaluation value.

[0019] The above-mentioned general public evaluation module for the area around the transport origin / destination divides the 24 hours of a day into four time intervals, differentially stores population density weights by port and by time interval in the transport route data, determines the time interval to which the transport work time entered from the user terminal belongs, calculates the effective population density by multiplying the population density weight of that interval by the reference population density, applies this to the representative individual exposure dose by zone to calculate the collective dose around the port by time, weights the exposure dose by interval by applying the work time ratio for each interval when loading and unloading work is performed over multiple time intervals, and if transport work is planned in a time interval where the population density weight is above a predetermined threshold, provides the user terminal with a warning message regarding increased exposure due to transport during densely populated hours and a comparison value regarding the effect of reducing exposure dose during late-night transport, and sorts the exposure doses of each of the four time intervals in ascending order to automatically derive and provide the time interval with the lowest exposure dose as the recommended transport time. Effects of the invention

[0021] According to a radiation risk assessment system for the marine transport of radioactive waste in one embodiment, it is possible to systematically assess the radiation risk for each by distinguishing between normal operation conditions and accident conditions during the marine transport of radioactive waste.

[0022] In addition, the present invention enables customized risk assessment for each target by individually providing risk assessment modules for each exposure target, such as the general public near the transport origin / destination, ship crew members along the transport route, workers handling the transported goods, and the general public near the marine area where the accident occurred.

[0023] In addition, the present invention is equipped with a risk calculation unit comprising an external exposure dose rate calculation module, an internal exposure dose rate calculation module, an atmospheric diffusion factor calculation module, a deposition factor calculation module, and a risk spatial grid calculation module, thereby providing quantitative risk calculation results for various types of radiation exposure that may occur during maritime transport.

[0024] In addition, the present invention can ensure consistency and reproducibility in the assessment of radiation risk during maritime transport by systematically building transport data, radionuclide data, ship data, transport route data, weather data, and accident scenario data into a database and linking them with a risk assessment unit and a risk calculation unit.

[0025] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0027] FIG. 1 is a schematic diagram showing the interlocking structure of a radiation risk assessment system for offshore transport of radioactive waste according to one embodiment. FIG. 2 is a schematic diagram showing the configuration of a service server of a radiation risk assessment system for offshore transport of radioactive waste according to one embodiment. FIG. 3 is a schematic diagram showing the configuration of a database of a radiation risk assessment system for offshore transport of radioactive waste according to one embodiment. FIG. 4 is a schematic diagram showing the configuration of the risk assessment unit of a radiation risk assessment system for offshore transport of radioactive waste according to one embodiment. FIG. 5 is a schematic diagram showing the configuration of the risk calculation unit of a radiation risk assessment system for offshore transport of radioactive waste according to one embodiment. FIG. 6 is a schematic diagram showing the operation flow of the radiation risk assessment for offshore transport of radioactive waste according to one embodiment. Specific details for implementing the invention

[0028] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0029] All flowcharts, state transition diagrams, pseudocode, etc., which can be substantially represented on a computer-readable medium, should be understood as representing various processes performed by a computer or processor, regardless of whether the computer or processor is explicitly depicted.

[0030] The functions of the various elements illustrated in the drawings, including functional blocks represented as processors or similar concepts, may be provided by the use of dedicated hardware as well as hardware capable of executing software in conjunction with appropriate software. When provided by a processor, said functions may be provided by a single dedicated processor, a single shared processor, or a plurality of individual processors, some of which may be shared. Throughout the specification, the same reference numerals refer to the same components.

[0031] Terms such as "...part," "module," etc., as described in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or as a combination of hardware and software.

[0032] The contents within parentheses used in the specification may be examples. Specifically, where indicated as "Network (Bluetooth)," "Bluetooth" may be proposed as an example of "Network." In this case, the "Network" of the present disclosure is not limited to "Bluetooth," and "Bluetooth" is proposed as an example of "Network."

[0033] In this specification, "radioactive waste" refers to waste containing radioactivity generated during processes such as the operation of nuclear power plants, the reprocessing of nuclear fuel, the use and research of radioisotopes, and includes low-level, medium-level, and high-level radioactive waste.

[0034] In this specification, "cargo" refers to an article in which radioactive waste is contained in a transport container (package), and the types of cargo may be classified into Excepted Package, Industrial Package, Type A Package, Type B Package, etc., in accordance with the safety standards of the International Atomic Energy Agency (IAEA).

[0035] In this specification, "maritime transport" refers to the activity of transporting radioactive waste from a point of origin to a point of destination via a maritime route using a vessel, and includes loading and unloading operations at the point of origin and destination, stopping at an anchorage, and navigation along the transport route.

[0036] In this specification, "exposure" means the human body being exposed to radiation; "external exposure" refers to exposure to radiation emitted from a radiation source located outside the human body, and "internal exposure" refers to exposure to radiation emitted from radioactive material introduced into the body through routes such as inhalation or ingestion.

[0037] In this specification, "dose rate" refers to the amount of radiation (dose) received by the human body per unit time, and is generally expressed in units of millisieverts per hour (mSv / h) or microsieverts per hour (μSv / h).

[0038] In this specification, "atmospheric diffusion factor" refers to a factor that quantitatively indicates the degree of diffusion of radioactive material according to meteorological conditions such as wind direction, wind speed, and atmospheric stability after it is released into the atmosphere, and is used to calculate the concentration of radioactive material at a specific point.

[0039] In this specification, "deposition factor" refers to a factor that quantitatively indicates the extent to which radioactive material diffused into the atmosphere is deposited on the Earth's surface through processes such as gravitational sedimentation or washout by precipitation.

[0040] In this specification, the term "risk spatial grid" refers to a grid structure in which a maritime transport route and its surrounding area are divided into predetermined sizes to perform an assessment of radiation risk during maritime transport, and the radiation risk is calculated individually for each grid.

[0041] In this specification, "risk" refers to an indicator comprising at least one of the following: the exposure dose received by the subject, the expected dose reflecting the probability of an accident, and the limit utilization rate, which is the ratio of the exposure dose to the regulatory limit. Here, the expected dose refers to a probability-weighted dose calculated by multiplying the probability of a specific accident scenario occurring by the exposure dose at the time of the accident.

[0042] In this specification, the term "Transport Index (TI)" refers to a value calculated based on the maximum radiation dose rate at a distance of 1 meter from the outer surface of a radioactive material carrier, and signifies an indicator for controlling the loading and isolation distance of the carrier. Specifically, it may be defined as a value equal to the maximum dose rate at a distance of 1 meter (unit: mrem / h), or, if using the SI unit of microsievert / hour (μSv / h), as a value obtained by dividing the maximum dose rate at a distance of 1 meter by 10.

[0044] Specific embodiments will be described below with reference to the attached drawings.

[0045] FIG. 1 is a schematic diagram showing the interlocking structure of a radioactive waste offshore transport radiation risk assessment system (10) according to one embodiment.

[0046] Referring to FIG. 1, the radioactive waste offshore transport radiation risk assessment system (10) includes a service server (100) and a user terminal (200).

[0047] The service server (100) and the user terminal (200) are interconnected via a wired or wireless network. The service server (100) stores and manages various data regarding the maritime transport of radioactive waste, performs risk assessment and risk calculation, and provides the results to the user terminal (200).

[0048] The user terminal (200) is an electronic device such as a computer, tablet, or smartphone used by a radiation safety manager, transport planner, or person in charge of a regulatory agency, etc., and is used to access the service server (100) to input transport information, ship information, transport route information, etc., and to view risk assessment results.

[0049] The user terminal (200) can transmit and receive data with the service server (100) through a web browser or a dedicated application.

[0050] The network may include various forms of wired and wireless communication networks, such as the Internet, private networks (VPN), and dedicated communication networks, and encrypted communication protocols may be applied for the secure transmission of data related to radioactive waste.

[0051] Although the present invention has been described as being implemented as a combination between a service server (100) and a user terminal (200), it may also be implemented in the form of an application that runs independently within the user terminal (200), in which case some or all of the functions of the service server (100) may be performed independently within the user terminal (200).

[0053] FIG. 2 is a schematic diagram showing the configuration of a service server (100) according to one embodiment.

[0054] Referring to FIG. 2, the service server (100) includes a communication unit (110), a database (120), a risk assessment unit (130), a risk calculation unit (140), a result provision unit (150), and a control unit (160). The communication unit (110) is responsible for transmitting and receiving data with a user terminal (200) and an external system.

[0055] The database (120) stores and manages various data required for the radiation risk assessment of radioactive waste transport by sea. The risk assessment unit (130) performs risk assessments classified by exposure target, and the risk calculation unit (140) calculates various physical factors required for the risk assessment. The result provision unit (150) processes the results calculated by the risk assessment unit (130) and the risk calculation unit (140) into a form that can be viewed by the user and provides them. The control unit (160) generally controls the operation of each component of the service server (100). The components of the service server (100) will be described in detail below.

[0057] The communication unit (110) transmits and receives data to and from the user terminal (200) via a network and performs the role of receiving data necessary for radiation risk assessment from an external data source. The communication unit (110) receives input data such as transport information, ship information, transport route information, and weather information from the user terminal (200), and transmits the risk assessment results and calculation results to the user terminal (200).

[0058] For example, the communication unit (110) can receive data such as the departure port, arrival port, transit port, type and quantity of cargo, and specifications of the vessel used, which are input from the user terminal (200) when establishing a transport plan. In addition, the communication unit (110) can receive real-time or historical weather data from external agencies such as the Korea Meteorological Administration, and can receive marine accident statistics data from relevant agencies and store it in the database (120). The communication unit (110) may include a function to receive radioactivity concentration data in the marine environment in the event of a sinking accident from an external linkage system.

[0059] In addition, the communication unit (110) can ensure the confidentiality and integrity of data related to radioactive waste by applying secure communication protocols such as HTTPS (HyperText Transfer Protocol Secure) and TLS (Transport Layer Security). In another embodiment, the communication unit (110) can exchange data with an external system through a web service based on REST API (Representational State Transfer Application Programming Interface) or SOAP (Simple Object Access Protocol). In addition, the communication unit (110) can support FTP (File Transfer Protocol) or SFTP (SSH File Transfer Protocol) for large-capacity data transmission.

[0060] In this way, the communication unit (110) is a component that provides a communication interface for data exchange with a user terminal (200) and an external system, and performs the collection of input data and the distribution of evaluation results necessary for the assessment of radiation risk of radioactive waste transport by sea.

[0062] FIG. 3 is a schematic diagram showing the configuration of a database (120) according to one embodiment.

[0063] Referring to FIG. 3, the database (120) includes transport data (121), radionuclide data (122), ship data (123), transport route data (124), weather data (125), and accident scenario data (126). Each data stored in the database (120) is referenced by the risk assessment unit (130) and the risk calculation unit (140) and utilized for radiation risk assessment and calculation. Below, each data in the database (120) will be described in detail.

[0064] The database (120) is a component that systematically stores and manages various data required for the assessment of radiation risk of the maritime transport of radioactive waste. The database (120) can be implemented based on a relational database management system (RDBMS), and for example, database management systems such as Oracle, MySQL, and PostgreSQL can be used. The data stored in the database (120) is managed by classifying it into normal operation conditions and accident conditions. During normal operation, common codes (cargo, section, other codes) and ship codes (ship information, transport section, anchorage, ship cargo, work) are systematically classified and stored, and during an accident, common codes (cargo, cargo radionuclide, other code, ingestion, weather, release rate) and ship codes (ship information, accident location, ship cargo, exposure target) are systematically classified and stored.

[0065] In addition, the database (120) can store unstructured data by using a NoSQL database in parallel, and can also efficiently manage hourly changes in weather observation data through a time series database.

[0066] In this way, the database (120) manages all data related to the maritime transport of radioactive waste in an integrated manner and performs the role of providing data necessary for risk assessment and calculation quickly and accurately.

[0067] The transport data (121) stores information regarding radioactive waste transports that are subject to maritime transport. The transport data (121) includes information such as the type of transport (exempt transport, industrial transport, Type A transport, Type B transport, etc.), the external dimensions and weight of the transport, the maximum dose rate on the external surface of the transport, the Transport Index (TI) of the transport, the amount of radioactivity of the radioactive waste contained in the transport, and the shielding structure and material of the transport.

[0068] For example, in the case of a Type B carrier, the thickness of the internal shielding, the gamma ray dose rate and neutron dose rate on the external surface may be recorded. The carrier data (121) may be structured according to the carrier classification system defined in the International Atomic Energy Agency (IAEA) Safe Transport Regulations for Radioactive Materials (SSR-6), and may be managed by reflecting the carrier standards defined in the domestic Nuclear Safety Act and its subordinate regulations. The information stored in the carrier data (121) is referenced by each evaluation module of the risk assessment unit (130) and the external exposure dose rate calculation module (141) of the risk calculation unit (140), etc.

[0069] The radionuclide data (122) stores information regarding radioactive nuclides contained in radioactive waste contained in the transport. The radionuclide data (122) includes information such as the name of the nuclide, half-life, radioactivity (Bq), the type and energy of the emitted radiation (alpha rays, beta rays, gamma rays, neutron rays), the radiation weighting factor of the nuclide, the dose conversion factor for each nuclide, and the internal exposure dose factor due to inhalation and ingestion of the nuclide. For example, in the case of Cobalt-60 (Co-60), information such as a half-life of 5.27 years, gamma ray energy of 1.17 MeV, and 1.33 MeV is recorded. The radionuclide data (122) can be constructed based on dose factor data provided in publications of the International Commission on Radiological Protection (ICRP) and can reflect technical standards of domestic specialized institutions such as the Korea Institute of Nuclear Safety (KINS). In some embodiments, the radionuclide data (122) may be configured to include decay chain information for each radionuclide, so as to calculate changes in radioactivity over time due to decay from a parent radionuclide to a daughter radionuclide. The radionuclide data (122) is referenced by the external exposure dose rate calculation module (141), internal exposure dose rate calculation module (142), etc. of the risk calculation unit (140) and utilized for calculating the dose rate.

[0070] Ship data (123) stores information regarding a ship used to transport radioactive waste by sea. Ship data (123) includes information such as the ship's name, gross tonnage (GT) and deadweight tonnage (DWT), the ship's length, width and draft, the ship's maximum speed and cruising speed, the ship's cargo hold structure and the loading location of radioactive waste carriers, the number of ship crew members, the distance between the ship crew's work location and the loading location of carriers, and the ship's shielding structure. For example, in the case of a dedicated radioactive waste carrier, the carrier securing device inside the cargo hold, the spacing between carriers, and the material and thickness of the shielding wall may be recorded. Ship data (123) may be managed by reflecting the requirements for the maritime transport of radioactive materials set forth in the International Maritime Dangerous Goods Code (IMDG Code) of the International Maritime Organization (IMO), an international organization related to maritime affairs. The ship data (123) is referenced by the transport route ship crew evaluation module (132) of the risk assessment unit (130), etc.

[0071] The transport route data (124) stores information regarding the transport route used for the maritime transport of radioactive waste. The transport route data (124) includes information such as the name and coordinates of the departure port, the name and coordinates of the arrival port, the name and coordinates of the transit port, the sailing distance and time required for each section, the location and time of anchorage, the maritime traffic volume for each section, the rate of collision and sinking accidents in each section, and the population density around the departure / arrival / anchorage. For example, regarding the route from a nuclear power plant port in Korea to a radioactive waste disposal facility port, the sailing distance for each sea area, major maritime traffic congestion zones, and sea areas with significant weather influence may be recorded. The transport route data (124) may be constructed based on maritime traffic statistics and marine accident statistics provided by agencies such as the Ministry of Oceans and Fisheries and the Korea Coast Guard. The transport route data (124) is referenced by the general public evaluation module (131) around the transport origin / destination of the risk assessment unit (130), the transport route ship crew evaluation module (132), and the risk spatial grid calculation module (145) of the risk calculation unit (140).

[0072] Weather data (125) stores information regarding weather conditions along the sea transport route of radioactive waste. Weather data (125) includes information such as wind direction, wind speed, temperature, humidity, atmospheric stability (Pasquill-Gifford classification, etc.), precipitation amount, precipitation type (rain, snow, etc.), sea level pressure, direction and speed of ocean currents, and wave height. Weather data (125) can be constructed based on real-time observation data or historical weather statistical data provided by agencies such as the Korea Meteorological Administration and the Korea Hydrographic and Oceanographic Agency. The Pasquill-Gifford atmospheric stability classification classifies the degree of atmospheric turbulence mixing into six categories (A: very unstable, B: unstable, C: slightly unstable, D: neutral, E: stable, F: very stable) and is a representative classification system used to predict the degree of atmospheric dispersion of radioactive materials. The weather data (125) is referenced by the atmospheric dispersion factor calculation module (143) and deposition factor calculation module (144), etc., of the risk calculation unit (140) and used to calculate the degree of atmospheric dispersion and surface deposition of radioactive material. In some embodiments, the weather data (125) may be used to predict future weather conditions, including output data of a numerical weather forecasting model.

[0073] Accident scenario data (126) stores information regarding various accident situations that may occur during the maritime transport of radioactive waste. The accident scenario data (126) includes information such as the type of accident (collision, sinking, grounding, fire, etc.), the severity level of the accident, the degree of damage to the transport at the time of the accident, the release fraction of radioactive material, the form of the released radioactive material (gas, aerosol, particulate matter, etc.), the accident rate for each type of accident, the duration of the release of radioactive material at the time of the accident, the classification of transport damage according to the speed and size of the colliding vessel in the event of a collision, and the scenario of radioactive material leakage in the seabed environment in the event of a sinking accident. For example, in the case of a collision accident, the damage level of the transport's shielding structure according to the collision energy is classified, and the release fraction of radioactive material for each level may be recorded. The accident scenario data (126) may be constructed based on the transport accident assessment methodology of the International Atomic Energy Agency (IAEA) and transport accident statistical data from each country. The accident scenario data (126) is referenced by the general public evaluation module (134) near the accident occurrence ocean of the risk assessment unit (130) and each calculation module of the risk calculation unit (140). As described above, the database (120) comprehensively manages data regarding the transport, radionuclides, vessels, transport routes, weather, and accident scenarios required for the radiation risk assessment of the maritime transport of radioactive waste, and performs the role of providing base data for the risk assessment unit (130) and the risk calculation unit (140) to perform accurate assessments and calculations.

[0075] FIG. 4 is a schematic diagram showing the configuration of a risk assessment unit (130) according to one embodiment.

[0076] Referring to FIG. 4, the risk assessment unit (130) includes a general public assessment module (131) around the transport origin / destination, a transport route ship crew assessment module (132), a transport handling worker assessment module (133), and a general public assessment module (134) near the accident site. The risk assessment unit (130) classifies the subjects who may be exposed to radiation during the maritime transport of radioactive waste into four groups and performs an individualized risk assessment for each group. Below, each module of the risk assessment unit (130) will be described in detail.

[0077] The risk assessment unit (130) is a component that quantitatively evaluates the radiation risk for each exposed target by referring to the transport data (121), radionuclide data (122), ship data (123), transport route data (124), and accident scenario data (126) stored in the database (120), and applying the calculation results of the dose rate, atmospheric dispersion factor, deposition factor, etc. calculated by the risk calculation unit (140). The risk assessment unit (130) evaluates the risk under normal operating conditions and the risk under accident conditions separately, and can calculate the overall risk for the corresponding transport case by integrating the evaluation results of the two conditions. In some embodiments, the risk assessment unit (130) can calculate a risk index that combines the probability of an accident occurring and the accident result by applying the Probabilistic Safety Assessment (PSA) methodology. In this way, the risk assessment unit (130) plays the role of performing a detailed risk assessment according to the characteristics of the exposed target and the exposure scenario.

[0078] The general public assessment module (131) for the area around the transport departure / arrival port assesses the radiation risk to the general public living or working near the departure and arrival ports of the radioactive waste transport by sea. The general public assessment module (131) for the area around the transport departure / arrival port calculates the degree of exposure to radiation emitted from the transport to the general public near the port during the process of the transport being loaded onto the ship at the departure port and unloaded from the ship at the arrival port.

[0079] Specifically, the general public evaluation module (131) around the transport origin / destination calculates individual exposure doses for each representative receptor set at a designated location within or around the port, such as the port boundary, nearest residential area, and major traffic point. The individual exposure dose is calculated by applying the time required for loading and unloading of the transport and the time spent at the port to the dose rate by distance from the representative receptor location calculated by the external exposure dose rate calculation module (141), and further reflecting the occupancy factor at the location and the dose reduction effect caused by physical shielding (buildings, walls, etc.) of the port. Additionally, the general public evaluation module (131) around the transport origin / destination can calculate a collective dose by applying population distribution or population density information around the port. The collective dose is calculated by multiplying the representative individual exposure dose of each zone, subdivided by direction and distance from the port, by the population of that zone and summing the results; this allows for the quantitative representation of the radiation exposure impact of the shipment on the entire community surrounding the port.

[0080] Additionally, the general public evaluation module (131) around the transport origin / destination can individually reflect the dose reduction effect caused by physical shielding (buildings, walls, etc.) of the port for each representative recipient. In another embodiment, the population fluctuation around the port due to night transport and day transport can be reflected in the occupancy rate to perform a differentiated risk assessment by time of day.

[0081] In this way, the general public evaluation module (131) around the transport departure / arrival port is a component that quantitatively evaluates and provides the radiation exposure effects on individuals and the community during the loading and unloading process at the departure and arrival ports by calculating the individual exposure dose based on representative receptor standards and the collective dose reflecting the population distribution around the port, respectively.

[0082] The transport route ship crew evaluation module (132) evaluates the radiation risk to crew members aboard a ship transporting radioactive waste at sea. The transport route ship crew evaluation module (132) calculates the degree of continuous exposure of crew members to radiation emitted from the transport material throughout the entire transport route in which the ship sails from the departure point to the destination point.

[0083] For example, the transport route ship crew evaluation module (132) refers to the distance between the ship crew's work location and the cargo loading location from the ship data (123), refers to the time required for each section of the voyage from the transport route data (124), and calculates the cumulative exposure dose received by the crew during the entire transport route by applying the external exposure dose rate by distance calculated by the external exposure dose rate calculation module (141) of the risk calculation unit (140). At this time, the crew's shift rotation cycle, the crew's time of stay at each work location, and the shielding effect by the ship structure are taken into consideration.

[0084] Additionally, the transport route ship crew evaluation module (132) can subdivide the crew's work positions into the wheelhouse, engine room, cargo deck, etc., and calculate the dose rate at each position individually to perform a differentiated risk assessment by job. In another embodiment, the transport route ship crew evaluation module (132) can separately reflect the situation where the crew comes into close proximity to the cargo while the ship is anchored at the anchorage, thereby calculating exposures during anchoring and sailing separately.

[0085] The transport route ship crew evaluation module (132) is a component that evaluates the radiation exposure received by the ship crew throughout the entire process of maritime transport by comprehensively reflecting factors such as distance, time, and shielding.

[0086] The transport handling worker evaluation module (133) evaluates the radiation risk to workers who directly handle radioactive waste transport. The transport handling worker evaluation module (133) calculates the degree to which a worker is exposed to radiation emitted from the transport during various work processes performed in close proximity to the transport, such as loading and unloading of the transport, securing and releasing of the transport, and inspection and check of the transport.

[0087] For example, the transport handling worker evaluation module (133) refers to the external surface dose rate by type of transport from the transport data (121), and calculates the exposure dose in each work process by applying the distance between the worker and the transport and the time required for the work according to the type of work. Since the handling method and work time differ depending on the specifications of the transport, a differentiated evaluation is performed for each type of transport, such as exempt transport, industrial transport, Type A transport, and Type B transport.

[0088] Additionally, the transport handling worker evaluation module (133) can reflect the dose reduction effect caused by personal protective equipment (lead apron, radiation protection gloves, etc.) worn by the worker. In another embodiment, when using remote handling equipment such as a crane, the evaluation can be performed under conditions where the distance between the worker and the transport is increased.

[0089] In this way, the transport handling worker evaluation module (133) is a component that individually evaluates the radiation exposure received by a worker according to the specifications of the transport and the characteristics of the handling work, and provides radiation safety for the worker during the transport handling process.

[0090] The general public assessment module (134) for the accident-occurring sea area evaluates the radiation risk to the general public near the accident area when radioactive material is released externally due to an accident such as collision or sinking during the sea transport of radioactive waste. The general public assessment module (134) calculates the degree of external and internal exposure received by the general public located on land or at sea near the accident area when radioactive material released due to the accident spreads into the atmosphere or leaks into seawater.

[0091] For example, the general public evaluation module (134) near the accident site refers to the radioactive material release rate by accident type from the accident scenario data (126), refers to the characteristics of the released nuclides from the nuclide data (122), and applies the atmospheric dispersion factor calculated by the atmospheric dispersion factor calculation module (143) of the risk calculation unit (140) and the deposition factor calculated by the deposition factor calculation module (144) to calculate the external exposure dose (exposure due to exposure from radioactive clouds in the atmosphere and exposure due to deposition on the ground surface) and the internal exposure dose (exposure due to inhalation of radioactive material) of a general public located at a predetermined distance from the accident site, respectively.

[0092] Additionally, the general public evaluation module (134) near the accident site can distinguish between collision accidents and sinking accidents and apply radioactive material release and diffusion models suitable for each type of accident. In the case of a collision accident, atmospheric release due to damage to the shielding structure of the cargo is evaluated as the primary path, and in the case of a sinking accident, both the marine environmental impact due to leakage into seawater and atmospheric release can be considered for evaluation. In another embodiment, isopleth analysis can be performed at the time of the accident to calculate the size and shape of the area exceeding a predetermined dose standard.

[0093] Consequently, the general public evaluation module (134) near the accident site is a component that evaluates the radiation risk under accident conditions by comprehensively considering the external and internal exposure to the general public near the accident site caused by radioactive material released during a maritime transport accident.

[0095] FIG. 5 is a schematic diagram showing the configuration of a risk calculation unit (140) according to one embodiment.

[0096] Referring to FIG. 5, the risk calculation unit (140) includes an external exposure dose rate calculation module (141), an internal exposure dose rate calculation module (142), an atmospheric diffusion factor calculation module (143), an deposition factor calculation module (144), and a risk spatial grid calculation module (145). The risk calculation unit (140) performs the role of calculating and providing physical factors referenced by each evaluation module of the risk evaluation unit (130). Below, each module of the risk calculation unit (140) will be described in detail.

[0097] The risk calculation unit (140) is a component that calculates various physical factors necessary for radiation risk assessment by referring to the transport data (121), radionuclide data (122), ship data (123), transport route data (124), weather data (125), and accident scenario data (126) stored in the database (120). The calculation results calculated by the risk calculation unit (140) are referenced by each evaluation module of the risk assessment unit (130) and utilized for radiation risk assessment for each exposure target. The risk calculation unit (140) applies different calculation models for normal operation conditions and accident conditions, respectively, and performs calculations by considering additional physical processes such as the release of radioactive material, atmospheric diffusion, and surface deposition in accident conditions. In some embodiments, the risk calculation unit (140) may probabilistically simulate the radiation transport process by applying Monte Carlo simulation techniques. In this way, the risk calculation unit (140) performs the role of calculating quantitative factors for various types of radiation exposure occurring during the maritime transport process based on radiophysical principles.

[0098] The external exposure dose rate calculation module (141) calculates the external exposure dose rate caused by radiation emitted from the outer surface of the radioactive waste carrier. The external exposure dose rate calculation module (141) calculates the dose rate when the carrier's shielding structure is intact under normal operating conditions, and the dose rate when the carrier's shielding structure is damaged under accident conditions.

[0099] For example, the external exposure dose rate calculation module (141) refers to the type of radionuclide contained in the carrier, the amount of radioactivity, gamma ray energy, etc. from the radionuclide data (122), and refers to the shielding structure of the carrier, the material and thickness of the shielding body, etc. from the carrier data (121) to calculate the gamma ray dose rate at a predetermined distance from the carrier. The inverse square law based on the point source approximation may be applied to the calculation of the dose rate, and the dose attenuation by the shielding body is calculated by applying the mass attenuation coefficient for each material of the shielding body. The inverse square law is a physical principle in which the radiation intensity from a point source decreases inversely proportional to the square of the distance, and is a basic principle used in the field of radiation protection to predict changes in dose rate according to distance.

[0100] Additionally, the external exposure dose rate calculation module (141) can calculate a more accurate dose rate by applying line source approximation or area source approximation in the case of large carriers where the shape of the carrier is difficult to approximate as a point source. In another embodiment, the external exposure dose rate calculation module (141) can precisely calculate the dose rate of radiation passing through a complex shielding structure by utilizing Monte Carlo-based radiation transport codes such as MCNP (Monte Carlo N-Particle Transport Code) or FLUKA. Monte Carlo radiation transport codes are simulation tools that probabilistically track the movement paths of individual radiation particles to calculate dose distributions in complex geometric structures, and are utilized in shielding design and dose evaluation in the nuclear field.

[0101] In this way, the external exposure dose rate calculation module (141) is a component that calculates the external exposure dose rate by distance according to the characteristics of the transported object and shielding conditions, and provides basic data necessary for each evaluation module of the risk evaluation unit (130) to calculate the external exposure dose for each exposed target.

[0102] The internal exposure dose rate calculation module (142) calculates the internal exposure dose rate when radioactive material emitted from a carrier under accident conditions enters the human body through inhalation or ingestion. The internal exposure dose rate calculation module (142) calculates the effective dose due to internal exposure by applying the atmospheric concentration of the emitted radioactive material and the dose coefficient for each radionuclide.

[0103] For example, the internal exposure dose rate calculation module (142) refers to the release rate and release form (gas, aerosol, etc.) of radioactive material from accident scenario data (126), refers to the inhalation and intake dose coefficients for each radionuclide from radionuclide data (122), and applies the atmospheric concentration of radioactive material at a specific point calculated by the atmospheric diffusion factor calculation module (143) to calculate the effective dose rate of internal exposure by inhalation at that point. At this time, the average breathing rate of an adult (generally about 1.2 m³ / h) is applied, and the inhalation classification according to the chemical form of the radionuclide (inhalation particle size, residence time in the lungs, etc.) is considered.

[0104] In addition, the internal exposure dose rate calculation module (142) can calculate an internal exposure dose differentiated by age group, such as infants, children, adolescents, and adults, by applying the age-specific dose factor provided in the International Commission on Radiological Protection (ICRP) Publication No. 72. In another embodiment, internal exposure due to the ingestion route of radioactive material (oral ingestion through contaminated food, contaminated water, etc.) can be additionally calculated and added to the exposure due to the inhalation route.

[0105] Consequently, the internal exposure dose rate calculation module (142) is a component that calculates the internal exposure dose caused by the influx of radioactive material released due to an accident into the body by radionuclide and by path, and provides factors necessary for evaluating the radiation risk under accident conditions.

[0106] The atmospheric dispersion factor calculation module (143) calculates an atmospheric dispersion factor indicating the degree to which radioactive material released into the atmosphere under accident conditions is dispersed according to weather conditions. The atmospheric dispersion factor calculation module (143) calculates a diffusion coefficient to calculate the atmospheric concentration of radioactive material at a point located at a predetermined distance from the release point.

[0107] For example, the atmospheric dispersion factor calculation module (143) refers to weather conditions such as wind direction, wind speed, and atmospheric stability from weather data (125) and calculates the atmospheric dispersion factor in the downwind direction from the emission point based on the Gaussian Plume Model. The Gaussian Plume Model is a mathematical model that simulates the atmospheric dispersion of continuously emitted pollutants as a Gaussian distribution in the horizontal and vertical directions, and calculates the concentration of pollutants in the atmosphere using wind direction, wind speed, and diffusion coefficients (horizontal diffusion coefficient σy and vertical diffusion coefficient σz). The diffusion coefficients are determined according to the Pasquill-Gifford atmospheric stability classification, and as the atmosphere becomes more unstable, the diffusion coefficient increases, causing radioactive materials to spread over a wide area, and as the atmosphere becomes more stable, the diffusion coefficient decreases, causing radioactive materials to concentrate in a narrow area.

[0108] Additionally, the atmospheric dispersion factor calculation module (143) can simulate the atmospheric dispersion of instantaneously emitted radioactive material by applying a Gaussian Puff Model. Unlike the plume model, the Gaussian Puff Model can reflect variations in weather conditions over time, making it suitable for accident scenarios where wind direction changes rapidly or emissions occur instantaneously. In another embodiment, considering the specific characteristics of the marine environment, a modified atmospheric dispersion model can be applied that reflects the alternation of sea breezes and land breezes, and the characteristics of the oceanic-atmosphere boundary layer.

[0109] In this way, the atmospheric diffusion factor calculation module (143) is a component that quantitatively simulates the diffusion behavior of radioactive material released into the atmosphere during an accident according to weather conditions and provides an atmospheric diffusion factor for calculating the concentration of radioactive material at a specific point.

[0110] The deposition factor calculation module (144) calculates a deposition factor indicating the degree to which radioactive material diffused in the atmosphere is deposited on the surface of the earth. The deposition factor calculation module (144) calculates the surface contamination concentration due to dry deposition and wet deposition and provides a factor for evaluating radiation risk by ground survey.

[0111] For example, the deposition factor calculation module (144) refers to the concentration of radioactive material in the atmosphere calculated by the atmospheric diffusion factor calculation module (143), and in the case of dry deposition, calculates the deposition amount per unit area of ​​the surface by applying the deposition velocity according to the particle size of the radioactive material. In the case of wet deposition, it refers to the amount of precipitation and the type of precipitation from the weather data (125), and calculates the amount of radioactive material in the atmosphere removed to the surface by precipitation by applying the washout coefficient. Dry deposition is a phenomenon in which radioactive particles are deposited on the surface by physical processes such as gravitational sedimentation, diffusion, and inertial collision, and wet deposition is a phenomenon in which radioactive material in the atmosphere is removed to the surface by being contained in raindrops or snow particles during the process of precipitation such as rain or snow.

[0112] Additionally, the deposition factor calculation module (144) can apply a differential deposition rate according to the particle size distribution of radioactive material (gas, aerosol, fine particles, etc.) and can reflect changes in the deposition rate according to the characteristics of the surface (sea surface, land, grassland, city, etc.). In another embodiment, the surface exposure dose over a long period can be calculated by reflecting the weathering effect over time of the radioactive material deposited on the surface.

[0113] Consequently, the deposition factor calculation module (144) is a component that quantitatively calculates the process of deposition of radioactive material diffused into the atmosphere on the surface according to dry and wet mechanisms, and provides the deposition factor necessary for assessing radiation risk by ground survey.

[0114] The risk spatial grid calculation module (145) generates a spatial grid that divides the transport route and the surrounding area into a predetermined size to perform a maritime transport radiation risk assessment, and sets a radiation risk assessment point for each grid. The risk spatial grid calculation module (145) determines the range, size, and resolution of the grid based on transport route data (124), and assigns an accident rate to each grid cell.

[0115] For example, the risk spatial grid calculation module (145) refers to the coordinates of the departure port, arrival port, and navigation route from the transport route data (124) and sets the area extended by a predetermined width on both sides centered on the navigation route as the grid range. The grid size may be applied differentially depending on the characteristics of the sea area; for example, in coastal areas or areas with high maritime traffic, the grid size may be set relatively small to evaluate the risk with high spatial resolution, while in open areas, the grid size may be set relatively large. Each grid cell is assigned a collision and sinking accident rate in the corresponding sea area, and this accident rate is calculated based on maritime traffic volume and accident statistics data stored in the transport route data (124).

[0116] In addition, the risk spatial grid calculation module (145) can apply an adaptive grid technique to automatically subdivide the grid in areas with a high accident rate or near densely populated coastal areas, and automatically merge the grid in open areas with low risk, thereby ensuring both calculation efficiency and evaluation precision. In another embodiment, the risk spatial grid calculation module (145) can assign attributes such as the distance to the nearest coastline and the distance to the nearest densely populated area to each grid cell, so that the range of impact on nearby general public in the event of an accident can be quickly determined.

[0117] In this way, the risk spatial grid calculation module (145) is a component that supports the risk evaluation unit (130) in performing a spatially subdivided risk evaluation by expressing the spatial distribution on the maritime transport route as a grid structure and setting accident occurrence rates and risk evaluation points for each grid.

[0119] The result providing unit (150) processes the risk assessment results for each exposure target calculated by the risk assessment unit (130) and the various calculation results calculated by the risk calculation unit (140) into a form that can be viewed by the user and provides them to the user terminal (200). The result providing unit (150) can process and provide the risk assessment results in various visualization forms such as numerical data, tables, graphs, and maps.

[0120] For example, the result providing unit (150) can generate a result report summarizing the exposure dose for each exposure target (general public near the departure / arrival point, ship crew, cargo handling workers, and general public near the ocean at the time of an accident). The result providing unit (150) can generate a risk distribution map that displays the risk level for each grid on the transport route by color-coding on the map in conjunction with grid data generated by the risk spatial grid calculation module (145). In the case of evaluation results under accident conditions, the isopleth analysis results can be superimposed on the map to visually display the range of the area exceeding a predetermined dose standard.

[0121] Additionally, the result providing unit (150) may include a function to output evaluation results in various file formats such as PDF, Excel, and CSV, and may include a function to automatically edit the results to fit the format of a transport safety evaluation report submitted to a regulatory agency. In another embodiment, the result providing unit (150) may include a function to present evaluation results for a plurality of transport scenarios by comparing and analyzing them, which can be utilized by the user to select the optimal transport route and transport conditions.

[0122] Consequently, the result providing unit (150) is a component that processes the output results of the risk assessment and calculation so that the user can intuitively understand them, and systematically provides information necessary for decision-making.

[0124] The control unit (160) generally controls the operation of each component of the service server (100), namely the communication unit (110), database (120), risk assessment unit (130), risk calculation unit (140), and result provision unit (150). When the control unit (160) receives a risk assessment request from a user terminal (200), it retrieves necessary data from the database (120), calls each calculation module of the risk calculation unit (140) to calculate physical factors, and then controls the execution of each assessment module of the risk assessment unit (130) sequentially or in parallel to perform a risk assessment for each exposure target.

[0125] For example, when a user requests a risk assessment for a new transport case, the control unit (160) verifies whether input data such as transport information, vessel information, transport route information, and weather information is complete, and after confirming the validity of the input data, initiates the assessment process. The control unit (160) distinguishes between the assessment of normal operation conditions and accident conditions, calls the calculation module and assessment module corresponding to each condition, and controls the transmission of the comprehensive result to the user terminal (200) through the result providing unit (150) once the execution of all assessment modules is completed.

[0126] Additionally, the control unit (160) can monitor the progress status of the risk assessment process and track whether each step is completed, and notify the user terminal (200) of the progress status in real time. In another embodiment, the control unit (160) supports batch processing for a large number of transport scenarios, so that risk assessments for multiple transport cases can be automatically executed sequentially.

[0127] In this way, the control unit (160) is a component that manages the overall operation flow of the radioactive waste marine transport radiation risk assessment system (10) and coordinates the data flow and execution order between each component so that the radiation risk assessment is performed systematically.

[0129] FIG. 6 is a diagram schematically showing the operation flow of the radiation risk assessment for offshore transport of radioactive waste according to one embodiment (10).

[0130] Referring to FIG. 6, the operation flow of the radioactive waste offshore transport radiation risk assessment system (10) is as follows.

[0131] When a risk assessment request is received from a user terminal (200), the control unit (160) verifies whether input data such as cargo information, ship information, transport route information, and weather information is complete and confirms its validity (S601).

[0132] The control unit (160) determines the operation classification and performs evaluations of normal operation conditions and accident conditions in parallel or sequentially (S602).

[0133] The following steps are performed in the evaluation of normal operating conditions.

[0134] The external exposure dose rate calculation module (141) of the risk calculation unit (140) calculates the external exposure dose rate by distance when the shielding structure of the transported object is intact (S603).

[0135] The general public evaluation module (131) around the transport origin / destination of the risk assessment unit (130) calculates the collective dose reflecting the individual exposure dose and population distribution around the origin and destination ports by applying the calculated dose rate to the representative recipient location, the transport route ship crew evaluation module (132) calculates the cumulative exposure dose of the ship crew by applying the crew work location information and voyage time of the ship data (123), and the transport handling worker evaluation module (133) calculates the exposure dose of the handling worker by applying the transport type information of the transport data (121) (S604).

[0136] The following steps are performed in the evaluation of accident conditions.

[0137] The risk spatial grid calculation module (145) generates a spatial grid for the transport route and assigns an accident rate to each grid cell (S605).

[0138] Based on accident scenario data (126), the external exposure dose rate calculation module (141) calculates the dose rate under shielding structure damage conditions, the atmospheric diffusion factor calculation module (143) calculates the atmospheric diffusion factor according to weather conditions, the deposition factor calculation module (144) calculates the surface deposition factor, and the internal exposure dose rate calculation module (142) calculates the internal exposure dose rate due to inhalation (S606).

[0139] The general public evaluation module (134) near the accident site combines these calculation results to calculate the external and internal exposure doses of the general public near the accident site. The accident types are classified into collision accidents and sinking accidents. In the case of a collision accident, a release rate is applied according to the cargo damage grade based on the severity of the accident, and in the case of a sinking accident, a scenario of radioactive material leakage in the seabed environment and radioactivity concentration data, which is external linked data, are additionally applied (S607).

[0140] When the evaluation of normal operating conditions and accident conditions is completed, the control unit (160) integrates the evaluation results of the two conditions to calculate the overall risk level for the transport case (S608).

[0141] The result providing unit (150) processes the calculated evaluation results into a form such as a report, table, graph, or risk distribution map and provides them to the user terminal (200) (S609).

[0143] In some embodiments, the result providing unit (150) may calculate and provide the annual cumulative dose for maritime transport that is performed repeatedly multiple times on the same route, along with the risk assessment results for a single transport case. Specifically, the result providing unit (150) refers to the annual scheduled number of transports (N) stored in the transport route data (124), and multiplies the annual number of transports (N) by the exposure dose to the general public around the port of a single transport case (D1) calculated by the general public evaluation module (131) around the transport origin / destination, the cumulative exposure dose to the ship crew of a single transport case (D2) calculated by the transport route ship crew evaluation module (132), and the exposure dose to the worker of a single transport case (D3) calculated by the general public evaluation module (131) around the transport origin / destination, respectively, to obtain the annual cumulative dose (N) for each exposure target. D1, N D2, N Calculate D3). For example, if the single exposure dose of a general public near a port is 0.05 mSv and the annual transport frequency is 12 times, the annual cumulative exposure dose of the general public is calculated as 0.60 mSv / yr.

[0144] Additionally, the result providing unit (150) can automatically compare the calculated annual cumulative exposure dose with the International Commission on Radiological Protection (ICRP)’s annual dose limit for the general public (1 mSv / yr) ​​and the domestic regulatory standards notified by the Nuclear Safety and Security Commission to calculate the ratio of the actual exposure dose to the regulatory limit (hereinafter “limit utilization rate”) for each exposure target. If the limit utilization rate exceeds a predetermined warning threshold (e.g., 70%), the result providing unit (150) can provide a message to the user terminal (200) recommending a review of safety improvement measures for the relevant transport plan, such as reducing the number of transports, changing the transport route, or strengthening shielding. For example, if the limit utilization rate of the ship crew is calculated to be 75%, the result providing unit (150) can output a notice such as, “Since the annual exposure dose of the ship crew in the current transport plan reaches 75% of the regulatory limit, we recommend reducing the number of annual transports or adjusting the crew rotation cycle.”

[0145] Additionally, the result providing unit (150) can automatically calculate and provide the maximum allowable annual number of transports (N_max) such that the annual cumulative exposure dose of each exposed target does not exceed the regulatory limit, using the annual number of transports (N) as a variable. N_max is calculated in the following manner: for each exposed target, the value obtained by dividing the annual dose limit (D_limit) by the single exposure dose (D_single) (D_limit / D_single) is calculated, and the smallest value among all exposed targets is determined as N_max. For example, if the single exposure dose of the general public around the port is 0.05 mSv, N_max = 1 mSv / 0.05 mSv = 20 times, and if the single exposure dose of the ship crew is 0.08 mSv, N_max = 20 mSv / 0.08 mSv = 250 times (based on occupational exposure limit), so the final N_max is determined to be the most restrictive 20 times and is provided to the user terminal (200) as the upper limit of the transport plan. Through this, the user can quantitatively determine the maximum number of transports permissible within the regulatory limit and use this as an upper limit constraint when establishing a transport plan.

[0146] In addition, the result providing unit (150) can calculate and provide a monthly cumulative exposure dose distribution by reflecting the seasonal distribution of the annual transport plan. Specifically, by referring to the monthly scheduled transport frequency stored in the transport route data (124) (e.g., once a month during the winter season from December to February, twice a month during the summer season from June to August, etc.) and applying the monthly representative weather conditions (wind direction, wind speed, atmospheric stability, etc.) stored in the weather data (125), the risk assessment for the same route is performed by month, and then the monthly exposure doses for 12 months are summed to calculate the final annual cumulative exposure dose distribution. In this way, the result providing unit (150) in some embodiments can provide a more realistic and precise long-term risk indicator to the user compared to a simple summation of a single assessment result by providing an annual exposure dose distribution that reflects both the weather conditions and transport frequency that change according to the season.

[0147] Meanwhile, the result providing unit (150) can calculate the annual cumulative exposure dose and the allowable maximum number of transports for each of the multiple transport route candidates, and provide the results of the comparative analysis to the user terminal (200) in a table format. For example, when comparing Route A and Route B, Route A has a short sailing distance and thus a short transport time, but passes through a densely populated coastal area, so the exposure dose to the general public around the port is relatively high; on the other hand, Route B has a long sailing distance and thus a long transport time, but uses a long-distance route from the coast, so even if the exposure dose to the general public around the port is low, the exposure dose to the crew may be high. The result providing unit (150) can synthesize these multiple route comparison results and recommend the route that minimizes the sum of the annual cumulative exposure dose as the "optimal transport route," or present multiple route scenarios in parallel so that the user can directly select the balance between the number of transports and the exposure dose. In this way, the result providing unit (150) functions as a long-term radiation safety analysis tool for the entire annual transport plan beyond the evaluation of a single transport case, and plays a role in providing quantitative grounds for medium-to-long-term radiation protection decision-making to transport planners and regulatory agency officials.

[0149] In some other embodiments, the risk spatial grid calculation module (145) receives real-time location information of a transport vessel from the Automatic Identification System (AIS) through the communication unit (110), and can dynamically recalculate the risk based on the current vessel location by updating the risk spatial grid at a predetermined interval (e.g., 15 minutes) based on the received location information. The AIS is an international standard system used for maritime traffic control and collision prevention, and is a device that automatically transmits information such as GPS location, speed, and route of a vessel. The risk spatial grid calculation module (145) converts the received current vessel location into a grid coordinate system, recalculates the risk of nearby grid cells based on the location, and stores it as a history in the database (120). At this time, if it is detected that the vessel has deviated by more than a predetermined distance (e.g., 5 nautical miles) from the pre-set transport plan route, a new grid range corresponding to the deviation route is automatically generated, and sea area characteristic data (sea traffic volume, coastal population density, etc.) to be applied to the grid is retrieved from the transport route data (124) and updated.

[0150] Additionally, the control unit (160) can determine that the risk level based on the current location, recalculated by the risk spatial grid calculation module (145), rises to 130% or more of the pre-evaluation value (the reference risk level of the corresponding grid calculated when establishing the transport plan), and can issue an automatic alarm to the administrator of the user terminal (200) through the result providing unit (150). The automatic alarm includes the current ship location coordinates, the risk increase rate, and factors determined to be the cause of the risk increase (increase in maritime traffic density, deterioration of weather, deviation from the planned route, etc.). Additionally, when a risk increase event occurs, the control unit (160) can automatically search for an alternative route to derive an alternative grid route from the current location to the destination where the risk level is less than 100% of the pre-evaluation value, and include this in the alarm message to support the decision-making of the operator to change the route.

[0151] Additionally, the risk spatial grid calculation module (145) may include a function to generate a post-evaluation report by analyzing the history of risk changes by grid across the entire operation history after the completion of the voyage. Specifically, by analyzing time-series data of risk values ​​by grid recorded at 15-minute intervals during the operation, the section with the highest risk (hotspot grid), the weather conditions at that time, and the ship's location are extracted, and the difference between the actual operation conditions and the plan is quantitatively reported by comparing this with the pre-evaluation value. In this way, the risk spatial grid calculation module (145) in some embodiments goes beyond static risk evaluation in the pre-planning stage and performs the role of integrating real-time risk monitoring during operation and post-verification after the completion of the voyage into a single continuous safety management system.

[0153] In some other embodiments, the general public evaluation module (131) around the transport origin / destination can calculate a radiation dose that is differentiated according to the time of transport work by subdividing the day into multiple time intervals when calculating the radiation dose to the general public around the port and applying population density weights set differently for each interval. Specifically, the 24 hours of the day are divided into four time intervals: 00 to 06 (night), 06 to 12 (morning), 12 to 18 (afternoon), and 18 to 24 (evening), and population density weights (e.g., night 0.2, morning 0.8, afternoon 1.0, evening 0.6) for each port and time interval are stored in the transport route data (124) of the database (120). The general public evaluation module (131) around the transport departure / arrival point determines the time interval to which the transport operation time (departure time, arrival time, and scheduled loading / unloading time) entered from the user terminal (200) belongs, calculates the effective population density by time by multiplying the population density weight of the interval by the reference population density, and then applies this to the representative individual exposure dose by zone to calculate the collective dose around the port based on the transport operation time.

[0154] Additionally, the general public evaluation module (131) around the transport origin / destination can automatically derive the optimal transport time interval where the exposure dose is below a predetermined threshold value based on the calculated exposure dose per time interval and provide it to the user terminal (200) through the result providing unit (150). For example, the general public evaluation module (131) around the transport origin / destination can individually calculate the exposure dose of the general public around the port for each of the four time intervals, sort the results in ascending order, and present the time interval with the lowest exposure dose as the "recommended transport time." Additionally, time intervals where the population density weighting is above a predetermined threshold (e.g., 0.9) are classified as "daytime transport intervals," and if transport work is planned in these intervals, the result providing unit (150) provides a comparison value of the exposure dose reduction effect during nighttime transport along with a message warning of increased exposure due to transport during densely populated times.

[0155] In addition, the general public evaluation module (131) around the transport origin / destination can calculate the cumulative exposure dose for the entire loading and unloading operation period by applying the ratio of work time for each section to weighted sum the exposure dose for each section when the loading and unloading operation is performed over multiple time sections. For example, if a total of 4 hours of unloading operation is carried out over 2 hours in the afternoon section (12-18 o'clock) and 2 hours in the evening section (18-24 o'clock), the exposure dose for 2 hours with the afternoon section population density weight (1.0) applied and the exposure dose for 2 hours with the evening section weight (0.6) applied are calculated and summed respectively, thereby providing a more accurate exposure dose for the general public around the port under mixed time section transport conditions. In this way, the general public evaluation module (131) around the transport origin / destination in some other embodiments is a component that performs an exposure evaluation of the general public around the port at a detailed level that reflects even the population fluctuations by time, and quantitatively presents to the user a methodology to effectively reduce potential exposure doses through the optimization of transport work times.

[0156] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0158] 10: Radiation Risk Assessment System for Maritime Transport of Radioactive Waste 100: Service Server 110: Communications Department 120: Database 121: Cargo data 122: Nuclide Data 123: Ship Data 124: Transport route data 125: Weather data 126: Accident Scenario Data 130: Risk Assessment Department 131: Public Evaluation Module Around Transport Origin / Destination 132: Transport Route Ship Crew Evaluation Module 133: Material Handling Worker Evaluation Module 134: Public Assessment Module for the Area Near the Accident Ocean 140: Risk Calculation Unit 141: External Exposure Dose Rate Calculation Module 142: Internal Exposure Dose Rate Calculation Module 143: Atmospheric Diffusion Factor Calculation Module 144: Precipitation Factor Calculation Module 145: Risk Spatial Grid Calculation Module 150: Result provider 160: Control unit 200: User terminal

Claims

Claim 1 A system comprising a service server that stores data regarding the maritime transport of radioactive waste and performs radiation risk assessment and calculation, and a user terminal that receives risk assessment results by inputting transport information, vessel information, and transport route information, wherein the service server comprises a communication unit that transmits and receives data to and from the user terminal and an external system, a database that stores and manages data necessary for the radiation risk assessment of the maritime transport of radioactive waste, a risk assessment unit that performs risk assessments classified by exposure target, a risk calculation unit that calculates physical factors necessary for the risk assessment, a result providing unit that processes the calculation results of the risk assessment unit and the risk calculation unit and provides them to the user terminal, and a control unit that controls the components of the service server, wherein the risk includes at least one of the exposure dose received by the exposure target, the expected dose reflecting the probability of an accident, and the limit utilization rate which is the ratio of the exposure dose to the regulatory limit, and the database comprises the coordinates of the departure port, arrival port, and transit port, the sailing distance and time required for each section, the anchorage location and anchoring time, the maritime traffic volume for each section, and each section The risk assessment unit stores transport route data including the occurrence rate of collision and sinking accidents, population density around the departure point, arrival point, and anchorage, and population density weights by port and time interval, and the risk assessment unit includes a general public assessment module around the transport departure / arrival port that assesses the radiation risk to general public residing or working around the departure and arrival ports of the transport, a transport route vessel crew assessment module that assesses the radiation risk to crew members aboard the maritime transport vessel, a transport handling worker assessment module that assesses the radiation risk to workers directly handling radioactive waste transport, and a general public assessment module near the accident sea that assesses the radiation risk to general public near the accident area when radioactive material is released in the event of an accident during maritime transport, and the risk calculation unitIt includes an external exposure dose rate calculation module that calculates the dose rate when the carrier shielding structure is intact under normal operating conditions and the dose rate when the carrier shielding structure is damaged under accident conditions, respectively; an internal exposure dose rate calculation module that calculates the internal exposure dose rate when radioactive material released from the carrier under accident conditions enters the human body through inhalation or ingestion; an atmospheric diffusion factor calculation module that calculates an atmospheric diffusion factor indicating the degree of diffusion of radioactive material released into the atmosphere under accident conditions according to meteorological conditions; a deposition factor calculation module that calculates the surface contamination concentration caused by dry deposition and wet deposition of radioactive material diffused into the atmosphere; and a risk spatial grid calculation module that generates a spatial grid by dividing the maritime transport route and surrounding area into a predetermined size and assigns an accident occurrence rate to each grid cell, wherein the risk spatial grid calculation module receives real-time location information including the GPS position, speed, and route of the transport vessel from the AIS (Automatic Identification System) through the communication unit The control unit receives the real-time location information, converts it into a grid coordinate system, updates the risk spatial grid based on the current vessel position at predetermined intervals, recalculates the risk of nearby grid cells, and if it is detected that the transport vessel has deviated from the pre-set transport plan route by more than a pre-set reference distance, automatically generates a new grid range corresponding to the deviation route, and queries and updates sea area characteristic data including maritime traffic volume and coastal population density to be applied to the new grid range from the transport route data, and the control unit determines this as a risk increase event if the risk based on the current position, recalculated by the risk spatial grid calculation module, rises by more than a pre-set ratio of the pre-evaluated value, which is the reference risk of the corresponding grid calculated when establishing the transport plan, and the current vessel position coordinates, risk increase rate,and controls the issuance of an automatic alarm to the user terminal through the result providing unit, including causes of increased risk such as at least one of increased maritime traffic density, deterioration of weather conditions, or deviation from the planned route; and when the increased risk event occurs, controls the automatic search for an alternative grid route from the current location to the destination where the risk level is less than 100% of the pre-evaluated value and provides it along with the automatic alarm; the general public evaluation module around the transport origin / destination divides the 24 hours of the day into four time intervals: 00–06, 06–12, 12–18, and 18–24; determines the time interval to which at least one of the departure time, arrival time, and scheduled loading / unloading time input from the user terminal belongs; calculates the effective population density by time by multiplying the population density weight of the corresponding time interval by the reference population density; calculates the collective dose around the port based on the transport operation time by applying the effective population density by time to the representative individual exposure dose by zone; and if the loading / unloading operation is performed over multiple time intervals, the operation for each interval A radiation risk assessment system for the offshore transportation of radioactive waste that applies a time ratio to weighted sum the exposure dose for each section, provides a warning message regarding increased exposure due to transportation during densely populated hours and a comparative value regarding the effect of reducing exposure dose during nighttime transportation to the user terminal when transportation is planned in a time section where the population density weight exceeds a predetermined threshold, individually calculates the exposure dose to the general public around the port for each of the four time sections, sorts the calculated exposure doses in ascending order, and automatically derives and provides the time section with the lowest exposure dose as the recommended transportation time. Claim 2 In claim 1, the database further comprises: cargo data including the type of cargo, external dimensions, weight, maximum external surface dose rate, carrier index (TI), radioactivity, shielding structure and material; radionuclide data including the name of the radionuclide, half-life, radioactivity, type and energy of radiation, radiation weighting factor, dose conversion factor, and internal exposure dose coefficient due to inhalation and ingestion; ship data including the name of the ship, gross tonnage (GT), deadweight tonnage (DWT), maximum speed, cargo hold structure, cargo loading location, number of crew, and distance between the crew duty location and the cargo loading location; meteorological data including wind direction, wind speed, temperature, humidity, Pasquill-Gifford atmospheric stability classification, precipitation amount, precipitation type, sea level pressure, and direction and speed of ocean currents; and accident scenario data including accident type, accident severity grade, degree of cargo damage, release fraction, release type, accident rate, and duration of radioactive material release. Radiation risk assessment system for the marine transport of stored radioactive waste. Claim 3 delete Claim 4 In paragraph 1, the result providing unit refers to the annual scheduled number of transports (N) stored in the transport route data, calculates the annual cumulative exposure dose for each exposure target by multiplying the single-time port-area general public exposure dose calculated by the general public evaluation module around the transport origin / destination, the single-time ship crew cumulative exposure dose calculated by the transport route ship crew evaluation module, and the single-time handling worker exposure dose calculated by the transport handling worker evaluation module by the annual number of transports (N), respectively, and calculates the limit utilization rate for each exposure target by comparing the calculated annual cumulative exposure dose with the annual dose limit for the general public of the International Commission on Radiological Protection (ICRP) and domestic regulatory standards, and if the limit utilization rate is greater than or equal to a preset ratio, provides a message to the user terminal recommending a review of safety improvement measures such as reducing the number of transports, changing the transport route, or strengthening shielding, and automatically sets the smallest value among the values ​​obtained by dividing the annual dose limit (D_limit) for each exposure target by the single-time exposure dose (D_single) as the maximum allowable annual number of transports. A radioactive waste marine transport radiation risk assessment system that calculates and provides to the above user terminal. Claim 5 delete

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