Detectors utilized for nuclear material safeguards have been using scintillation detectors which are inexpensive and highly portable, and electrically cooled germanium detectors which are expensive but have excellent energy resolution. However, recently IAEA, the only international inspectorate of nuclear material safeguards for the globe, have replaced the existing scintillation detector and electrically cooled germanium detector with a CdZnTe detector owing to the improved performance of room-temperature semiconductors significantly. In this paper, we will examine the spectrum features of the CdZnTe detector such as spectrum shape, energy resolution, and efficiency in the energy region of interest, which are the important characteristics for measuring Uranium enrichment. For this purpose, it would be conducted to compare its spectrum features using CdZnTe, NaI, HPGe detectors. The main energies of interest include 185.7 keV and 1,001 keV, which are the decay energies of uranium 235 and uranium 238. The results of this study will provide a better understanding of the spectral features of various detectors used in uranium enrichment analysis, and are expected to be used as basic data for future related software development.

Nuclear safety, security, and safeguards (nuclear 3S) are essential components for establishing robust nuclear environments. Nuclear safety is to protect public and environments from radioactive contamination, which can be caused in accidents. Nuclear security is to protect nuclear facilities from terrorism or sabotage, which related to physical a ttacks or insider threats. And nuclear safeguards is to protect nuclear materials from extortion by a state with a purpose of weaponizing activities. When a new nuclear facility is introduced, it is possible to save abundant amount of resources by considering nuclear 3S in an early stage (design phases). Initially, the international atomic energy agency (IAEA) recommended safeguards-by-design (SBD) approach. The concept of SBD gradually expands to nuclear 3S-by-design (3SBD). Though there are differences in purpose and target subject, each nuclear ‘S’ is closely related with others. When introducing a certain technology or equipment in order to enhance one ‘S’, another ‘S’ also get affected. The effect can be synergies or conflicts. For instance, confidential information in nuclear security is required for a safeguards activity. On the contrary, inspection equipment for safeguards can be used for security. Pyroprocessing is a technology for managing used nuclear fuels. As pyroprocessing is a backend fuel cycle technology, a sensitive nuclear technology, safeguards has taken a large portion of nuclear 3S research in an effort to achieve international credibility and nuclear transparency. As mentioned, there are both synergies and conflicts in integrating nuclear 3S. In this study, we investigate potential challenges in applying nuclear 3S integration to pyroprocessing by addressing synergies and conflicts. This approach will suggest required supplementary methods to build the reliable pyroprocessing environment.

Nuclear fusion energy is considered as a future energy source due to its higher power density and no emission of greenhouse gas. Therefore, various researches on nuclear fusion is being conducted. One of the key materials for the nuclear fusion research is tritium because the D-T reaction is the main reaction in the nuclear fusion system. However, that tritium can also be used for non-peaceful purposes such as hydrogen bombs. Therefore, it is necessary to establish the safeguards system for tritium. In that regards, this study analyzed the possibility of applying safeguards to tritium. To achieve this objective, the tritium production capacity through the light water reactor was analyzed. Tritium Production Burnable Absorber Rod (TPBAR) was modeled through the MCNP code, and tritium production was analyzed. The TPBAR is composed of a cylindrical tube with a double coating of aluminum and zirconium, filled with a sintered lithium aluminate (LiAlO2) pellet to prevent the release of tritium. Tritium is produced by the reaction of Li-6 in the TPBAR with neutrons, and it is extracted and stored at the Tritium Extraction Facility (TEF). As a result, the tritium production increased as the burnup and Li-6 mass increased. In addition, when the tritium produced in this way was transferred to TEF and extracted through the process, the application of safeguards measures was analyzed. To this end, various safeguards measures were devised, such as setting an Material Balance Area (MBA) for TEF and analyzing Material Balance Period (MBP). As there is no designated Significant Quantity (SQ) for tritium, cases were classified based on the type and form of nuclear weapons to estimate the Sigma MUF (Material Unaccounted For) of the TEF. Finally, the comprehensive application of safeguards to tritium was discussed. This research is expected to contribute to the establishment of IAEA safeguards standards related to tritium by applying the findings to actual facilities.

Milling facilities, which belong to the front end of the nuclear fuel cycle, are essential steps for utilizing uranium in nuclear power generation. These milling facilities currently provide the International Atomic Energy Agency (IAEA) with the location and annual production capacity of the facility through the Additional Protocol (AP, INFCIRC/540) and grant IAEA inspectors on-site sampling authority to apply safeguards to the facility. However, since milling facilities process a large amount of nuclear material and the product uranium ore concentrate (UOC) is bulk material, the absence of accounting for the facility could pose a potential risk of nuclear proliferation. Therefore, this study proposes technical approach that can be utilized for safeguards in milling facilities. Since the half-life of uranium isotopes is much longer than that of its daughter, they reach the secular equilibrium condition. However, after milling process, the fresh tailing showed the break of that secular equilibrium. As time goes on, they newly reach another secular equilibrium condition. Based on this observation, this study discussed the feasibility of the ratio method in safeguards purpose. The scenario applied in this study was 1% of uranium mill tailing. It was observed that the U-238/Th-234 and U- 238/Pa-234m ratios in fresh milling tails varied as a function of time after discharging, particularly during the first one year. This change can be worked as a significant signature in terms of safeguards. In conclusion, the ratio method in mill tails could be applicable for safeguards of nuclear milling facility.

Korea Institute of Nuclear Non-proliferation and Control (KINAC) Safeguards division and Export control division operate regulation management system each other according to their work scope and characteristics. Korea Safeguards Information System (KSIS) of Safeguards division handles information for nuclear material accounting and control. Especially, accounting and declaration reports submitted to International Atomic Energy Agency (IAEA) are important information in this system. And Nuclear Import and Export Control System (NEPS) of Export control division deals with import and export information of nuclear materials and nuclear weapon trigger list items. Establishing and operating the integrated database as sharing information between KSIS and NEPS derive merits as follows. First, the full cycle of nuclear material transfer records can be managed by collecting information on the nuclear materials from import to export or disposal. In addition, regulatory body can verify inconsistency between transfer records and account records in date, location, element, mass etc. Especially, small quantity nuclear materials are major loop hole in nuclear material accountancy system. The accumulated material transfer data will give an evidence to catch loss nuclear material. Second, sharing the information on nuclear fuel cycle related research and development activities in both divisions can utilize the information to outreach on facility subject to nuclear technology transfer for Nuclear Suppliers Group (NSG) and additional protocol declaration for Safeguards Agreement with IAEA. Third, regulatory body is easily able to manage entire import and IAEA report procedure for items subject to the Nuclear Cooperation Agreement (NCA). In present, KINAC regulation on NCA is divided to Export control and Safeguards. Export control division conducts classification imported items subject to NCA and acquires prior consent or notifies to other country. And Safeguards division report inventory list for each NCA country to the ROK government once a year. Imported NCA inventory list will be generated automatically by merging database. Then, it can be easily verified without any additional process by both divisions.

To ensure the peaceful use of nuclear energy, nuclear safeguards are applied in member states of the International Atomic Energy Agency (IAEA) under the Non-Proliferation Treaty. The two major considerations in implementing nuclear safeguards are effectiveness and efficiency. In terms of efficiency, the IAEA has a great interest in using containment and surveillance (C/S) technology to maintain continuity of knowledge. A representative means of C/S technology is a sealing system to detect tampering. The existing sealing systems used by the IAEA are of limited functionality in realtime verification purposes. To address this limitation, the present study develops a real-time verification sealing system. First, we analyzed the design requirements of a sealing system proposed by various institutions including the IAEA, the U.S. Nuclear Regulatory Commission, and a number of national laboratories and companies. Then, we identified the appropriate design requirements of this system for real-time verification. Finally, the prototype system was developed and tested based on the identified design requirements. The validation tests of the prototype system were performed for anticipated environmental conditions, radiation resistance, and safeguards functionality. Additionally, we are developing user-friendly verification software. The software validation is planned to perform for functionality, performance efficiency, and security. The next step is to develop a commercialized realtime verification sealing system based on the results of validation tests. Using this commercialized system, we plan to evaluate the performance in various actual use cases. Such a system is expected to significantly enhance the efficiency of nuclear safeguards.

Dry storage cask facilities are considered for temporary storage of spent nuclear fuels before their final disposal. According to relevant domestic laws and regulations, the integrity and gross defects of the PWR spent fuel must be inspected before they are transferred to the dry cask from a wet storage pool of a nuclear power plant. To meet nuclear safeguards requirements for a spent fuel transportation, the KINAC has been working to develop a simple and convenient Non-destructive Testing (NDT) equipment to verify the integrity and gross defects of the spent fuel assembly. This study was conducted in two processes. The first stage is to review the current NDT techniques conducted in the nuclear fuel manufacturing process. During the manufacturing process, the Ultrasonic testing (UT) and Eddy Current Testing (ECT) technique are used for detecting the cracks or foreign materials in a cladding of a fresh fuel. During an over-haul period after an end of one fuel cycle, the sipping test of the spent fuel is performed for detecting the failed fuel assemblies. If it is determined through the sipping test whether any fuel assembly contains a failed fuel rod, the failed fuel rod of lots of fuel rods in the assembly is found out using the UT instrument. The ECT is used for detecting the internal defects and oxide layer thickness of a fuel cladding. Because the UT and ECT are the wellknown technique and has already been employing for the spent fuel inspection, we adopted the UT and ECT technique for development of a new instrument for nuclear safeguards verification. The second stage is to design the UT and ECT equipment in consideration of nuclear safeguards activities in the spent fuel pool. For nuclear safeguards inspection, irradiated fuel or non-fuel items are distinguished. Thus, verification equipment newly designed using the UT and ECT should detect not only a failed rod, but also a false tube, or a false rod, or a different material from a cladding. New probe and signal processing methods are developed to achieve these goals. The design of UT and ECT probes are preferentially carried out according to technical requirements – the probe thickness including a damper material should be less than 1.0 mm - and the study on analyzing signal distortion caused from material difference will be conducted for development of the safeguards inspection equipment. Detailed results of our study will be discussed in this conference.