Once decommissioning begins, it is expected that large amount of radioactive wastes will be produced in a short period of time. The expected amount of radioactive wastes from Kori unit 1 NPP are approximately 80,000 drums (base on 200 L). By minimizing the amount of radioactive wastes generated through decontamination and reduction, KHNP has set the final target for the amount of radioactive wastes to be delivered to the disposal site at approximately 14,500 drums. Here, plasma torch melting technology is an essential technology for radioactive wastes treatment during nuclear power plants decommissioning and operation, because of its large volume reduction effects and the diversity of disposable wastes. KEPCO KPS was able to secure experience in operating Plasma Torch Melter (PTM) by conducting a research service for ‘development of plasma torch melting system advancement technology’ at KHNP-CRI. This study will compare kilo and Mega-Watt class PTM, largely categorized into facility configurations, operating parameters, and waste treatment. Based on this study, it would be desirable to operate PTM with approximate capacity according to the frequency and amount of waste production, and suggest volume for a kilo and Mega-watt class plasma torch in the melting furnace respectively. This plays to its strengths for both a kilo and Mega-watt class PTM.

When exporting nuclear-related items, export control is required from two perspectives: the control of “Trigger List Items” as controlled by Nuclear Supplier Groups (NSG) and the control of the “Items Subject to the Agreement” as specified in bilateral Nuclear Cooperation Agreements. While Trigger List Items and Items Subject to the Agreement are largely similar, there are some items where they do not overlap. Furthermore, national law for controlling each item is different. The Trigger List Items are governed by the Foreign Trade Act, and the Items Subject to the Agreement (Internationally Controlled Items) are governed by the Nuclear Safety Act. As a result, the detailed procedures and requirements for controlling each item are quite distinct. For the Trigger List Items, export license must be obtained in accordance with the Foreign Trade Act. The details such as responsible authority, the items subject to license, license requirements and procedures, penalties are specified in the Public Notice on Import and Export of Strategic Goods. For the Items Subject to the Agreement, the process and obligations set forth in bilateral agreements and related administrative agreements are fulfilled in accordance with the Nuclear Safety Act. However, in contrast to the Trigger List Items, the details for complying with the agreements are not specified legally. Since most of the Items Subject to the Agreement are fall within the category of the Trigger List Items, the obligations in accordance with the agreements are reviewed and implemented during the export license assessment process. However, if the Items Subject to the Agreement are not are fall within the category of the Trigger List Items, there is a risk of control omission. For example, this applies to cases of exporting tritium and tritium removal facilities, which are not the Trigger List Items, to Canada and Romania. Moreover, since subjects to the agreement and compliance procedures are respectively different for 29 bilateral Nuclear Cooperation Agreements signed with different countries, it is difficult for enterprise to recognize the appropriate procedures and obligations under the agreement by their own. The bilateral Nuclear Cooperation Agreements establish legal obligations between state parties while NSG are non-legally binding arrangements. Therefore, it could be even more necessary to comply strictly with the agreements. Consequently, legal improvements are required for effective implementations of Nuclear Cooperation Agreements. While it may be challenging to institutionalize details of 29 Nuclear Cooperation Agreements, it is essential to legally specify key elements such as the list of items subject to agreements, responsible authority, requirements and procedures for implement the agreement obligations, and penalties. Furthermore, domestic awareness on compliance with Nuclear Cooperation Agreements is lower compared to the system of export license for Trigger List Items. The continuous outreach is also necessary, along with institutional improvements.

Korea has signed nuclear cooperation agreements (NCA) with 29 countries. Nuclear materials, materials, equipment, and technology transferred under the agreements are “internationally controlled materials (ICM)” under the Nuclear Safety Act. The main obligations imposed on those items include ensuring peaceful use, safeguards, physical protection, annual inventory reporting, and retransfer with supplier prior consent. The Nuclear Export and Import Control System (NEPS) handles the export control procedures for transferring ICM. After import, inventory management for ICM in Korea would be transitioning to an item-based system through the Obligation Tracking System for internationally controlled item (OTS) currently under development. A one-stop import and export control system for ICM can be established when information is well-linked between these two systems. This paper aims to derive a methodology for integrating NEPS and OTS. NEPS-OTS coupling begins at the receipt confirmation and shipment notification stages in NEPS. When importing ICM under NCA, the inventory change (code RF: receipt foreign) is entered in OTS by getting the information that has completed the receipt confirmation in NEPS. Conversely, during export, the information that has completed the shipment notification procedure in NEPS is linked to the OTS so that the entire cycle from import to re-export of the ICM can be concluded. Inventory verification for retransfer, checking that the book inventory remains positive value, is impossible under the current system. This issue can be resolved by enabling inventory information in OTS to be displayed in NEPS. Determining when and how to generate the obligation code for imported ICM is essential for NEPS-OTS coupling. Manual input may be necessary for some cases with multiple obligations. Nevertheless, it is more efficient from a system communication protocol to automatically generate and impose a single obligation based on the supplier country information in NEPS. Moreover, it is important to automatically link crucial information available in NEPS to reduce the administrative burden on OTS users and discrepancies between systems. Most required OTS data, such as country obligation, item categories, quantity, physical or chemical form, and receipt date, can be directly linked from NEPS. However, NEPS improvement is needed for digitizing the receiver information and facility data, like the material balance area. The NEPS-OTS integration involves sharing data as a system and encompasses the connection between export control and inventory management. Future work to link some information in NEPS -OTS with the KSIS could be suggested to enhance efficiency and effectiveness in managing ICM.

The ROK government has developed the Nuclear Export and Control System (NEPS) to implement export control activities. Although it was launched in 2008 as a system that can work with classification, licensing, nuclear material approval, government-to-government assurance, complying with nuclear cooperation agreement (NCA) handled through official documents. In order to enhance systematic management for items subject to NCA, KINAC developed a new module for the procedure (hereinafter referred to as “NCA module”) and opened it in 2022. This paper presents the module’s development background, key features, and current operation status. The NCA module prioritizes functional expansion and flexibility, distinct from other tasks for the following reasons. First, the export control duties of classification, export license, and approval for NM are based on domestic law, leading to predetermined target items, application forms, and processes that change only through statutory amendments. In contrast, the implementation of NCA has numerous procedural variables, varying across countries in scope, content, and procedures. Therefore, if the function is over-standardized, there would be many exceptions that the system cannot resolve in practice. Second, the existing NEPS process entails a one-time decision or approval for each application, while the implementation of the agreement encompasses four related procedures for each item: prior notification, written confirmation, shipment notification, and receipt confirmation. Even some steps may be omitted depending on the case. The other difference is the working process. The implementation of NCA must be initiated from the government, so the existing methods, beginning with the licensee filling a form, cannot be adopted as it is. The NCA module has adopted a new reference numbering system to resolve these challenges. It enables the creation of multiple procedures under one reference number on an item to expand the tasks and make it possible to omit some steps or to reflect case-by-case concerns in each stage. It also provides a consolidated view of multiple notifications related to a single item, ensuring to deal with even long-running tasks without missing any obligations until the final procedure. Moreover, some of the data in the NCA module is extensible by allowing users to manage the list themselves. For example, the system can respond to new agreements by allowing users to add and modify codes that distinguish counterparty countries. As a result, the current NCA module accommodates a variety of implementation scenarios, including split shipments, the procedural omissions, and the modification of additional counterparties, offering enhanced flexibility and adaptability.

Gamma imaging devices that can accurately localize the radioactive contamination could be effectively used during nuclear decommissioning or radioactive waste management. While several hand-held devices have been proposed, their low efficiency due to small sensors have severely limited their application. To overcome this limitation, a high-speed gamma imaging system is under development which comprises two quad-type detectors and a tungsten coded aperture mask. Each quad-type detector consists of four rectangular NaI(Tl) crystals with dimensions of 146×146 mm2 and 72 square-type photomultiplier tubes (PMTs). The detectors are placed in front and back to serve as scatter and absorber, respectively, for Compton imaging. In addition, a coded aperture mask was fabricated in rank 19 modified uniformly redundant array pattern and placed in front of the scatter for coded aperture imaging. The system offers several advanced features including 1) high efficiency achieved by employing large-area NaI(Tl) crystals and 2) broad energy range of imaging by employing a hybrid imaging combining Compton and coded aperture imaging. The imaging performance of the system was evaluated through experiments in various conditions with different gamma energies and source positions. The imaging system provides clear images of the source locations for gamma energies ranging from as low as 59.5 keV (241Am) to as high as 1,330 keV (60Co). The imaging resolution was within the range of 7.5–9.4°, depending on gamma energies, when a hybrid maximum likelihood estimation maximization (MLEM) algorithm was used. The developed system showed high sensitivity, as the 137Cs source at distance, incurring dose rate lower than background level (0.03 μSv/h above background dose rate), could be imaged in approximately 2 seconds. Even under lower dose rate condition (i.e., 0.003 μSv/h above background dose rate), the system was able to image the source within 30 seconds. The system developed in the present study broadens the applicable conditions of the gamma ray imaging in terms of gamma ray energy, dose rate, and imaging speed. The performance demonstrated here suggests a new perspective on radiation imaging in the nuclear decontamination and radioactive waste management field.

For the export of nuclear materials (NM), the NSG guidelines require governmental assurance from the importing State that the NM will be used for peaceful purposes, safeguards and physical protection will be applied, and prior consent will be obtained for retransfer. By providing this assurance, the importing State (recipient) is responsible for fulfilling the obligations required by the exporting States (supplier). If the Nuclear Cooperation Agreement (NCA) has been concluded between the supplier and recipient, it may be replaced by implementing the procedures under the NCA. In the case of NM subject to this obligation, continuous management at the national level is required because prior consent from the supplier may be required for retransfer to a third party under the assurance or may be subject to annual reporting. The obligation swaps are the exchange of obligations of NM without the physical movement of it. Since the physical movement of NM is costly and risky, its obligations are often exchanged for commercial reasons. The basis for obligation swaps is the fungibility and equivalence of NM. The fungibility allows that the inventories of NM need not physically identify the particular NM originally obligated but identify an equivalent quantity of the same isotopic composition. In addition, under the principle of equivalence, even if NM loses its unique physical properties, it can be exchanged by another obligated or nonobligated NM. That is, the principles of equivalence and proportionality allow the comparison of quantities of uranium in different forms. Therefore, it is theoretically possible not only to exchange obligations between NM in same physical form, but also different physical forms of same composition (with the same enrichment), e.g., UO2 powder and its pellets. In U.S., it appears that there are obligation swaps of NM between different enrichment levels, but according to the NCA and its Administrative Arrangement between ROK and U.S., Canada and Australia, the principle of fungibility and equivalence shall not be used to reduce the quality of a quantity of NM. In other words, swaps between NM of different enrichment levels are not allowed under the NCA and AA. However, according to the Supplementary Arrangement between ROK and Canada, the replacement of NM by lower quality NM may only occur where the two States so decide following consultation. The U.S., Canada, and Australia, which are major suppliers of NMs, allow internal obligation swaps within the U.S. and the EU through NCA. The NCA between ROK and these countries does not address whether internal swaps are possible. Since governmental assurance does not impose restrictions on swaps, it can be considered if necessary. Although there is no actual practice of obligation swaps in ROK, research will be necessary regarding the extent to which swaps in ROK should be allowed and the need for government approval or permission.

A bilateral Nuclear Cooperation Agreement (NCA) should define what is subject to the agreement and when. Nuclear Materials (NM) are the subject of NCA with almost all countries, and the definition used in these agreements is borrowed from Article 20 of the IAEA Charter. The IAEA’s definition of NM as consisting of special fissionable material and source material and describes the types of material each contains. In order to control the export of NM under national laws and implement NCA, not only the types of NM but also quantitative criteria are required. This is because controlling small quantities of NM is impossible, unnecessary, and would create excessive administrative burdens. For this reason, the NSG guidelines establish a quantitative threshold of NM requiring control. Nevertheless, no quantitative thresholds have been agreed upon for NM subject to a NCA. Whether NM transferred is subject to the NCA is primarily a matter for the supplier states to determine. The supplier states make the decision based on quantitative criteria defined in their own export control laws. ROK identifies NM that require export licenses by reflecting the same criteria as the NSG guidelines in Foreign Trade Laws and its Notifications. Less than 500 kg of Natural Uranium, 1,000 kg of Depleted Uranium, 1,000 kg of Thorium, and 50 effective grams of special fissionable materials do not require an export license and is therefore not subject to NCA. In the US, the quantitative threshold for requiring an export license is different from that of ROK. For example, special fissionable materials that are not Pu are required if the individual shipment exceed 1 effective gram or 100 effective grams per year. The difference in the quantitative thresholds for NM between the two countries mean that the same item may be subject to NCA under US standards, but not under ROK’s. For example, the export of 8 grams of highly enriched uranium (93%) contained in a neutron detector would not be subject to the NCA in ROK, but would be considered NM subject to a NCA and required a special license in the US. Of course, in order to ensure the application of safeguards and physical protection to all NM transferred between the two countries, the agreement may not include a quantitative threshold for NM. However, the absence of such a threshold can lead to different conclusions by the two countries on the same item and make it challenging to control retransfers. The definition of quantitative standards will be necessary in the supplementary administrative arrangement for the practical control and management of NM subject to the NCA.

Under the Foreign Trade Act, an export license from the Nuclear Safety Commission is required to export items specified in Part 10 of Schedule 2 of the Public Notice of Exportation and Importation of Strategic Items (Trigger List Items). In the case of nuclear materials, deuterium, and heavy water, its cumulative amount determines whether it is trigger list item. An export license is required only if the cumulative amount exported to a single end-user country from January 1st to December 31st exceeds the regulation criteria. The reason for this cumulative control is to exclude small amounts of materials from the scope of control as they are considered less important in view of nuclear proliferation, but to prevent the possibility of acquiring large quantities of materials by importing small amounts several times. As a result, export control of nuclear material, deuterium, and heavy water requires different considerations than other Trigger List Items. First, materials exported by different companies must be consolidated to manage the cumulative amount. Second, it is necessary to continuously follow up the actual export status. If the material is not exported after it was classified as ‘non-Trigger List Items’, it should not be included in the cumulative amount. Third, there may be a difference between the accumulated quantities aggregated at the time of the classification and the time of the actual export. The classification should be changed if an export of the classified material is postponed or another export of same materials occurs before the export of the classified material. Fourth, the classification result of these materials should not be reused. Generally, the classification result could be reused within the expiration date (2 years) but in the case of substances. However, the reuse of classification result for materials should be limited as the classification results could be change depending on the cumulative amount. In addition, the sharing of classification results between different entities should also be restricted. The government approval procedures are required even for export of small amounts of nuclear materials which are less than the regulation criteria. The cumulative quantities of nuclear materials are systematically managed in the Nuclear Export & imPort control System (NEPS) through these procedures. NEPS is also linked to the custom clearance system of Korea Customs Service, which enables to track actual exports and the time of exports. However, cumulative quantities for the heavy water and deuterium are managed individually by classification reviewers. The annual export plans are received in advance from major entities which deal with the materials for nuclear uses, and the cumulative quantities for each application are managed manually. The systematic management has not been required as there were a few cases of exporting small quantities. However, systematic management may be required in the future as overseas expansion attempts from various companies in the nuclear field has been increasing. In addition, further study is needed on the criteria and system for calculating the cumulative amount. The time of aggregate the cumulative amount should be clarified by considering the difference between the time of classification and actual export. It is required to devise an efficient way to follow up the actual export.

An administrative agreement (AA) was signed between NSSC and UAE FANR in January 2023 under Article 5 of the ROK-UAE Nuclear Cooperation Agreement. The AA aims to enhance regulatory efficiency in safeguards and export control. This study reviewed the export control measures for the items subject to the agreement (ISA) and implementation procedures under ROK-UAE AA by comparing them with other countries cases. First of all, the ROK-UAE AA distinguishes between ISA and the inventory management target items. Technology is divided into two categories, one requiring consent for retransfer and the other, considering the characteristics of technology that is free to be copied and deleted, and thus less useful for inventory management. Only the former is included in the annual report, which differs from the ROK-Canada or ROK-Japan NCA, which includes all technologies subject to the agreements in the annual report. When ROK notifies export information, it is mandatory to specify whether the technology requires consent for retransfer. Furthermore, some technologies should be controlled as strategic information, even if excluded from the annual report, so efforts to prevent confusion are required. Secondly, the ROK-UAE AA covers all items in INFCIRC/254/rev.9/part1, unlike the ROK-U.S. and ROK-Canada NCA, which listed equipment subject to them. This is significant because it clarifies the criteria for regulation by increasing the consistency between the trigger list items in the domestic law and the ISA. However, the expanded ISA scope could result in some changes in export control procedures. For example, when importing nuclear material (NM) from the US, only uranium was controlled as ISA, and the packages were not considered. In contrast, when exporting fuel assemblies (FA) for UAE, both uranium and zirconium cladding should be treated as ISA. To this end, NEPS was improved to implement the features of the ROK-UAE AA. Consideration of the criteria and methods for imposing obligations under the agreement is essential because this is the first case of Korea concluded AA under exporting NPP and as a supplier of FA. Generally, the obligations for NM are imposed by the country of origin, conversion, and enrichment countries. Canada and EU recognize the fuel fabrication process as a substantial transformation and impose customs origin where the process takes place. Hence, NM fabricated from Canadian equipment is also subject to the same obligations as NM of Canadian origin. From this perspective, it would be appropriate to ensure ROK acts as a supplier and controls when exporting domestically manufactured FA. Moreover, a proper national obligation code system will be required to specify Korea’s control rights.

본 논문의 목적은 엘리엇의 시 재의 수요일에서의 앵글로가톨릭적 요소의 중요성에 대해 살펴보는 것이다. 이 시에서 시적 화자는 로널드 슈하드가 Eliot’s Dark Angel: Intersections of Life and Art에서 주목한 바 있듯 죄로 가득한 삶을 뒤로 하고 회개와 뉘우침을 향한 순례를 떠나고 있다. 또한 화자는 순례길을 떠나기에 앞서 마리아를 연상시키는 존재 인 “침묵의 여인”에게 간절한 기도를 올리고 있다. 시의 제목 역시 사람 들이 죄를 뉘우치고 부활절을 기다리는 시기를 가리킨다는 점에서 앵글 로 가톨릭적인 요소가 시를 끌어나가는데 중요한 역할을 한다고 볼 수 있다. 이러한 점에서 이 시는 “Journey of the Magi”와 네 사중주와 같 이 기독교적, 또는 앵글로 가톨릭 적인 주제가 드물게 등장하는 다른 시와는 다른 앵글로 가톨릭적인 시라고 볼 수 있다.

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.

The guidelines for cyber security regulations at domestic and foreign nuclear facilities, such as KINAC/RS-015, NRC’s RG5.71 and NEI 13-10, require the establishment of security measures to maintain the integrity of critical digital assets (CDAs) and protect them as threats to the supply process. According to the requirements, cyber security requirements shall be reflected in purchase requirements from the time of introduction of CDAs, and it shall also be verified whether cyber security security measures were properly applied before introduction. Domestic licensees apply measures to control the supply chain in the nuclear safety sector to cyber security policies. The safety sector supply chain control policy has areas that functionally overlap with the requirements of cyber security regulations, so regulatory guidelines in the safety sector can be applied. However, since most of the emergency preparedness and physical protection functions introduce digital commercial products, there is a limit to applying the control of the supply chain in the safety field as it is. It is necessary to apply supply chain control operator policies, procedures, and purchase requirements for each SSEP function, or to establish cyber security integrated supply chain control requirements. In this paper, based on the licensee’s current supply chain control policy, the cyber security regulation plan for supply chain control according to the SSEP (Safety-Security-Emergency Preparedness) function of CDAs is considered.

During decommissioning of a nuclear power plant, a large amount of radioactive waste is produced, and it is known to cost more than 300 billion won to dispose the waste. To reduce the disposal cost, it is essential to minimize the number of radioactive waste drums, which can be achieved by detecting and removing hotspot contaminations in the radioactive waste drums. Therefore, a Compton CT system for radioactive waste monitoring is under development, which provides the images of both the internal structure of the drum and the radioactive hotspot(s) in the drum. Based on the acquired information, the activity of hotspots can be estimated. The performance of the system is affected by various geometry factors. Therefore, it is essential to determine optimal configuration by evaluating the effects of the factors on the performance of the system. In the present study, we determined the optimum value of the factors and then predicted the performance of the optimized system by using a simulator based on the Geant4 Monte Carlo simulation. For optimization, the factors were evaluated in terms of structural similarity index measure (SSIM) and measurement time. The considered factors were the activity of the CT source, source to object distance (SOD), object to detector distance (ODD), and projection angle. The simulation result showed that the activities of the CT sources were determined as 23 mCi for 137Cs and 9.6 mCi for 60Co. The optimal SOD and ODD were 180 cm and 40 cm, respectively. The optimal projection angle was evaluated as 4° since it achieves the SSIM of 0.95 faster than other projection angles. With the optimized parameters, the performance of the system was evaluated using the IAEA gamma CT standard phantom containing a hotspot of 137Cs (7.02 μCi). The Compton image was reconstructed using the back-projection algorithm, and the CT image was reconstructed using the filtered back-projection algorithm. The result showed that the location of the hotspot in the Compton image was well identified at the true position. The acquired CT image also well represented the internal structure of the phantom, and the estimated mean linear attenuation coefficient value (μ= 0.0789 cm−1) of the phantom was close to the true value (μ= 0.0752 cm−1). In addition, the hotspot activity estimated by combining the information of the Compton image and CT image was 8.06 μCi. Hence, it was found that the Compton CT system provides essential information for radioactive waste drums.

The ROK conducts several export procedures, communications in connection with transfers; exchange of information on export plan, shipments, and receipt of nuclear materials, in accordance with bilateral Nuclear Cooperation Agreements (NCA) and Administrative Arrangements (AA) signed with US, Canada, and Australia. Also, the inventory amount of items subject to NCA has reported annually. This study reviewed the export procedures and management methods for spent nuclear fuel subject to NCA. The re-transfer procedures start with obtaining consent from the original exporting country. It is impossible to retransfer nuclear material without consent, whether long-term or individual case-bycase. If the material has multiple obligations, prior consent from all of those countries is required. Therefore, it is necessary to clarify the foreign obligated materials correctly. In general, nuclear fuel is subject to multiple obligations of all countries through which the materials have passed during the front-end fuel cycle. Then the new obligations are imposed on those irradiated materials or their by-products after ‘used-in’ or ‘produced through the use of ’ equipment subject to NCA. For example, fuel assemblies manufactured under CANDU fuel fabrication equipment subject to ROK-Canada NCA or burned in nuclear reactors where US equipment is installed have obligations based on Canada or US agreements. In order to impose obligation to irradiated materials, the principle of proportionality is applied as stipulated in each Agreement. According to the AA between US and ROK, nuclear materials used in the equipment transferred under the Agreement and produced through them are differently controlled. After the cycle in the reactor with US-made equipment, uranium in the irradiated fuel is considered a material used in the equipment. So it would be appropriate to apply obligation proportionality according to its origin, regardless the US-made equipment. Meanwhile, the obligation under US NCA is given to the entire amount of produced plutonium in the irradiated fuel. Although the contribution to the production of fuel is to be discussed case-by-case basis in the case of Canadian obligation, applying a similar method is proper. Since the fuel is burned in the form of bundles or assemblies, it is impossible to separate the spent fuel into uranium and plutonium physically. However, as discussed above, to clarify the rights and obligations pursuant to Agreement and ensure accuracy in inventory management, the obligation codes should be imposed on irradiated fuel as not a single item but separated individual substance of materials. Moreover, when an obligation swap occurs for the irradiated fuel, its movement and combustion history should be considered to prevent confusion in confirming multiple obligations and implementing export procedure.