Identifying plausible scenarios is necessary to evaluate the performance of the repository reliably over a very long period. All features, events, and processes (FEPs) expected in the repository should be comprehensively well-defined and structured into scenarios based on the relation analysis. A platform for the FEP DB management and relation analysis is needed to facilitate the efficient composition of the scenarios. For this purpose, the CYPRUS program was developed, but abandoned due to suspended FEPs and scenario research. Thus, it became necessary to build a new easy-tomaintain platform that inherits the legacy of CYPRUS and reflects the latest research. The data structure and user interface configuration were derived to develop a new platform. The new platform provides extensive data such as the assessment context, the FEP DB, the interaction between FEP contents, the relevance to other project FEPs, the influence on performance, the scenarios for the TSPA, the AMF, and the PA Data. The platform displays the long-term evolution FEPs developed by KAERI, the international and major project FEPs in table format. The correlation between FEP items is composed of a detailed interaction matrix and visualized as the chord diagram or arc diagram. The relevance and linkages between the project FEP items are mapped and presented in the form of network diagrams and network tables. The platform designed in this study will be used to manage the FEP DB, analyze and visualize the relationship between the FEP and scenarios, and finally construct the performance assessment scenarios. It is expected that the platform itself will be used as a part of the knowledge management system and facilitate efficient collaboration and knowledge exchange among experts.

The 2-round Delphi survey and Focus Group Interview (FGI) survey method, in this study, are sequentially applied for the level analysis of the high-level radioactive waste (HLW) management technologies, that are classified into transport/storage, site evaluation, and disposal categories. The 2- round Delphi survey was conducted on domestic 56 experts in the HLW field in Korea, and survey answers were managed with questionnaires distributed by e-mail. In the FGI survey, domestic 24 experts from management field were formed into three groups to conduct in-depth interviews. Past research achievements including journal papers, intellectual properties and the expert opinions presented at expert hearing on HLW technology were used as reference materials. As a result of the survey, in this study, the average domestic technology level compared to the leading countries was 83.1% in transport area, 79.6% in storage area, 62.2% in site evaluation area, and 57.4% in disposal area, respectively. When compared to the former level analysis results in 2017, technology level of transport-storage area increased by 8.6%, and the site evaluation-disposal technology area decreased by 7.27%. The highest factor that increase the level of technology in the transport-storage field was due to the increased R&D program resulting on journal papers, intellectual properties. In addition, the decrease factor in the level of technology in the site evaluation-disposal field was mainly due to relatively low R&D program when compared to the leading countries. Suggested method for the level survey can be used to find out the basic data of the lower tech technologies, to estimate the efficient research budgets and to prepare the R&D human resources. With this regards, R&D roadmap can be matured with suggested prediction method for the domestic technology level on HLW.

Currently, the most widely accepted disposal concept for long-term isolation of high level radioactive waste including spent nuclear fuels is to disposal in a deep geological repository designed and constructed with multiple barriers composed of engineered and natural barriers so that the waste can be completely isolated in a stable deep geological environment. In this concept, an important consideration is the heat generated from the waste due to the large amount of fission products present in the high level waste loaded in the disposal container. For safe and complete isolation of high level radioactive waste in the deep geology, the disposal concepts that meet the thermal requirements for the disposal system design have been developed by harmonizing the thermal characteristics of engineered and natural barriers in Korea. In this paper, the deposition hole configuration and the decay heat dissipation area (surface area) of disposal container were considered for the efficient thermal management in the deep geological disposal concept. Heat transfer through the waste form, its container and surrounding components and the rock will be mainly by conduction. Heat transfer by radiation and convection can be negligible after backfilling. When considering heat conduction, according to Fourier’s law, if the thermal conductivity of the repository components is the same, the greater the heat dissipation area and the adjacent temperature gradient, the greater the conduction effect. Therefore, rather than the conventional concept of loading 4 PWR spent fuel assemblies per disposal container and placing one disposal container in a deposition hole, it is better to load one assembly per disposal container and place 4 disposal containers in a deposition hole. In this case, it was found that the disposal area could be reduced through efficient thermal management. Considering this thermal management method as an alternative to the concept of deep geological disposal, additional research is needed.

Considering the domestic condition with small land area and high population density, it is necessary to develop technology that can reduce the disposal area than the deep geological disposal method. For this, KAERI is developing a nuclide management process that can reduce the environmental burden of spent fuel, and establishing an evaluation model that can evaluate the performance of various process options. It is expected that an optimal option of the nuclide management process can be derived from disposal perspective by applying the evaluation model. The mass flow between processing steps of the radionuclide management process is the basic quantity required to quantify the evaluation criteria. Therefore, we built a generalized block model on GoldSim, which can simulate mass flow of various radionuclide management process options. In addition to the mass flow, this model was established to derive the amount of wastes generated by each processing step, the composition of nuclides, and radiological properties (decay heat, radioactivity, etc.). The mass flow and waste property derived from the models are closely related to the factors that determine the area of disposal concepts. Based on this, a disposal area calculation model was established as a model to evaluate the effectiveness of the radionuclide management process on environmental burden reduction. For verification, three process options, which can manage radionuclides having high decay heat (Cs, Sr) or large volume (U), were selected and evaluated as reference processes. And two disposal options, deep geological disposal and deep borehole disposal concepts were considered to be linked with the processes. As a result, it was confirmed that the disposal area could be reduced in the process separating radionuclides having high decay heat. In the future, other evaluation models for economic viability and safety will be added in the GoldSim model.

Numerous spent nuclear fuels are generated every year in Korea. To solve the spent nuclear fuel problem within saturated temporary storage, the authorities are readying to build an interim storage and a permanent disposal facility in the country. At the same time, the authorities are readying to establish a management procedure for spent nuclear fuel. In the future, the authorities need to make and apply the Database of spent nuclear fuel to practice the management procedure. However, the structure of a traditional database is not reasonable for information management because it has a problem with listing data and identifying data features due to its structure. In addition, the traditional database always exists human error from working in Excel program by a human. Therefore, this research proposes a new standard information management model based on Semantic Web technique. Semantic Web uses a data structure named ontology. By using the ontology in the information database of the spent nuclear fuel, users, such as institutions related to management, could more easily recognize and understand the Database. Furthermore, since this task proceeds in the ontology construction program, the human error in the new model reduces rather than an environment of the traditional database.

Since SMR’s reduced reactor radius results in higher neutron leakage, SMR operates at a relatively lower discharge burnup level than traditional Light Water Reactors (LWRs). It may result in larger spent fuel amounts for SMRs. Furthermore, recent studies demonstrated that NuScale reactor will generate a significantly higher volume of low- and intermediate-level waste owing to components located near the active core including the core barrel and the neutron reflector. For spent nuclear fuel simulation, FRAPCON-4.0 was updated. Major modifications were made for fission and decay gas release, pellet swelling, cladding creep, axial temperature distribution, corrosion, and extended simulation time covering from steady-state to dry storage. In this study, typical 17×17 PWR fuel (60 MWd/kgU) and NuScale Power Module (36 MWd/kgU) was compared. NuFuel-HTP2™ fuel assembly, which has a half-length of proven LWR fuel, was employed. Owing to the lower discharge burnup and operating temperature, the maximum hydrogen pickup was 73 wppm and the maximum hoop stress was ~25 MPa. Therefore, hydride reorientation issue is irrelevant to SMR spent fuel. In this context, the current regulatory limit for dry storage (i.e. 400°C and 90 MPa) can be significantly alleviated for LWR-based SMRs. The increased safety margin for SMR spent fuel may compensate high spent fuel management cost of SMRs incurred by an increased amount. The comprehensive analysis on SMR spent fuel management implications are discussed based on simulated SMR fuel characteristics.

The nuclide management technology for separating high-heat generating/high-mobility/long-lived nuclides from high-level wastes based on the chemical reactions is under development. In order to secure the reliability of nuclear non-proliferation and to implement the effective safeguards, it is necessary to consider the safeguards from the conceptual design phase of the novel technologies. However, there was no experience and research on safeguards for the chemical reaction based nuclide management technology. In order to development the available monitoring techniques for the safeguards of nuclide management technology, the possible diversion scenarios were developed and the material flows of major nuclear materials were analyzed according to the various diversion strategies for each unit process in this study. The diversion strategies in this study is limited to the diversion of nuclear materials according to the change of operational parameters (temperature, chemical reagents, pressures, etc). The nuclear material distribution behaviors under the abnormal conditions were analyzed and compared with normal conditions using the HSC Chemistry. The results will be used to determine the proper signals and feasible techniques to monitor the abnormal operations.

The main purpose of the Bilateral Nuclear Cooperation Agreement is to obtain the prior consent of suppliers in the case of peaceful use of items covered by the agreement, application of IAEA safeguards, reprocessing, enrichment or transfer to a third country. Reports on inventory changes and status for mutually transferred obligated items should be exchanged annually. According to the Agreement, items subject to bilateral agreement information must be exchanged with each other prior to direct or indirect transfer of controlled items. And the importing country proceeds with prior confirmation. After that, upon receipt of the target item, shipment notification and shipment confirmation are made, and an annual report on the target item is made. Such as the Korea Atomic Energy Research Institute (KAERI), annual reporting and management of obligated items are made centered on institutions that use a lot of nuclear materials. But there are cases of delays in the agreement work due to the implementation, and discrepancies in data are occurring in the process of checking inventory details of obligated items. In addition, it was difficult to check the inventory of items subject to the agreement and the status of Export and Import status online, making it impossible for managers to monitor all aspects of bilateral agreements. Currently, there is generated to inconsistent in information between the annual report and the international transfer report in terms of Export and Import control. To solve these problems, KAERI is aim of promoting transparency in the international nuclear power sector and enhancing national reliability. And It is planning to establish an Export and Import management system for items subject to bilateral. In order to ensure the accuracy, it is going to enhance the efficiency of management methods such as new registration for new institutions when exporting and Importing items. This has the ultimate purpose of improving the efficiency of the implementation of the agreement items through the systemization of the database of agreement items and the management of the implementation of the agreement based on the sincere and timely implementation of the agreement.

The bilateral nuclear cooperation agreement provides the basis for technical and economic exchanges and research and development cooperation in the nuclear industry, while also having an important role in the peaceful use of nuclear power. The government of Republic of Korea has signed the supplementary and additional arrangements with the United States, Canada, and Australia to specify detailed procedures necessary for the implementation of the agreement. Currently, items under the bilateral nuclear cooperation agreement (i.e., obligated items) are managed through official documents and e-mails, and it is difficult for the government to systemically track item inventory and identify the person in charge. Another issue is the discrepancy of information between the annual report on obligated items and the report under the import and export procedure. In order to solve these problems, the government is establishing an import and export management system for obligated items to enhance transparency and national reliability in Korea. The ultimate purpose of this project is to not only faithfully fulfill the obligations under the bilateral nuclear cooperation agreement, but also to increase the efficiency of implementation work through systematization of databases and management of obligated items. In this paper, an improved management procedures are suggested by analyzing the required functions and problems. Also, this paper provides a conceptual design that can be applied to the management system for it obligated items by identifying and analyzing practical problems in the import and export management of mandatory items. As a result, key considerations and the conceptual design proposal for the ‘export and import management system for items subject to the nuclear bilateral cooperation agreement’ are derived. The result will be supplemented through continuous discussions with facility operators and the government to be utilized for detailed system design.

Under the bilateral nuclear cooperation agreements (NCA) and its administrative arrangement (AA), Korea annually exchanges the inventory of subject items (including nuclear materials (NM), non-nuclear materials, equipment, and related information) with US, Canada and Australia. Also, the government performs export control procedures such as notification or prior consent during importing and exporting of relevant items. It makes NCA a means of realizing the nuclear non-proliferation regime. However, it raises difficulties in management because the entity that uses and treats those items are end-user, not the authorities of AA, the government agency of each country. Accordingly, to increase the accuracy and effectiveness of item management at the national level, it is required to establish a system for the individual company that has the NCA items, considering the characteristics of each company. In this study, significant companies are classified into more than three types, and the management system of the items subject to the agreement is analyzed. Each company’s item management status has different characteristics depending on its role (position) within the entire nuclear fuel cycle, the type of facility, its possessed items, the main form of national trade, and the frequency of domestic movement. Those differences lead to diversity in the management systems currently owned by each company. For example, from the perspective of nuclear materials, institutions requiring bulk management have systematically organized their management system and obligation code program compared to the ‘item institutions’ that can track batch history for all facility inventory changes. Although Domestic law imposes only the duty of origin management on NMs, fuel manufacturers or research institutes have established their standard obligation codes to manage multiple obligations. The non-nuclear materials and equipment can be easily tracked and controlled by individual items. However, the management of NCA items is a complicated task involving various processes, from importing goods to using, storing, managing inventory change, selling to others, or fulfilling the obligations of AA when exporting. In particular, when the movement of items within a company or international trade occurs frequently, or when the end-users are diverse, the management difficulties increase. So a system that can accurately convey and track items subject to the AA is needed. In addition, since various entities are related, it is necessary to improve understanding of NCA items to increase the system’s utilization and effectiveness. The comparison result and requirement for system improvement based on the review above will be reflected in the history management system for items subject to NCA under development.