KINAC is trying to build a comprehensive aerial view of the nuclear material balance to predict North Korea’s weapons-grade nuclear material production capacity. We are creating a visualization model for North Korea’s nuclear facilities as part of these efforts. However, information on North Korea’s nuclear facilities is scarce, and it is not easy to consider additional facilities other than those already known. In addition, in the case of a model that targets only exceptional situations, it is not easy to secure objectivity for model validation, so it is necessary to upgrade to a general-purpose analysis tool that can be applied more generally. The following two examples are proposed as an analysis tool that can be a high degree of analysis. The first case is an Acquisition Path Analysis (APA) utilized to introduce IAEA’s State-Level Approach (SLA). The acquisition path analysis aims to find and evaluate the technically possible pathways to obtain nuclear materials for nuclear weapons or other nuclear explosive development. It can be an acquisition route if it is possible to produce at least 1 Significant Quantity (SQ) of weapongrade nuclear material within five years. The assessment of technologically feasible pathways is based on available information about the country’s past and present nuclear cycle capabilities. The second is the IAEA Physical Model. The IAEA Physical Model was carried out to introduce a comprehensive approach to all information on a country’s nuclear activities. It describes and characterizes the technologies and processes expressed at all levels of the acquisition path, depending on the development objectives. The IAEA Physical Model attempts a multi-tiered acquisition path analysis to identify all known technologies and processes in the nuclear fuel cycle, from raw material production to weapon usable material acquisition. Based on this analysis, the IAEA evaluates the signs of nuclear proliferation in a specific country. Based on the two cases discussed above, we intend to derive the following implications and priorities for extending the existing nuclear cycle model to a more general-purpose for a specific country. First of all, the requirements necessary to evaluate nuclear non-proliferation or verification of denuclearization must be at a level that the international community can recognize. In the stage of actual denuclearization verification, since verification will be conducted through the IAEA, a corresponding level of tools and technology will be required. From this point of view, the following is presented as a prerequisite for adding versatility to the existing physical model: It is necessary to derive all processes related to the nuclear cycle and standardize relevant indicators and data. In order to determine the signs of nuclear activity, detailed information on technologies, materials, by-products, and wastes, which are essential for each process, is required. For denuclearization verification, cumulative information from the past to the time point is required, and a comparative analysis of the operation history information of all facilities and the amount of nuclear material is required. To this end, it is necessary to make it possible to trace the history at every point where it can be determined that nuclear material has been diverted so that missing nuclear material can be found. Based on this, it is expected that it can be possible to evaluate a hypothetical threat state, but it is also expected that it will be easy to verify the model through the evaluation of easily accessible domestic facilities.

Molten salt reactor (MSR) has a unique characteristic using liquid fuel and/or coolant salt among six type of GEN IV reactors. Liquid fuels and on-site processing are fundamentally different from a solid fuel reactor where separate facilities produce the fresh solid fuel and process the Spent Nuclear Fuel. Because the choice of fuel cycle affects the safeguards and non-proliferation characteristics of the reactor system, different MSR concepts may have different proliferation resistance and physical protection characteristics. For example, MSR design variants that use solid fuel but are cooled with liquid salts such as FHR are very close to the Very High Temperature Reactor design concept. The composition of various fuel salts is a representative factor that makes it difficult to generalize the PRPP evaluation principle of MSR. In addition, the flow of molten salts containing fissile materials is also complex depending on the design of the reactor. The path through which radioactive materials travel not only inside the reactor but also to nuclear fuel cycle facilities can act as a difficult factor in measuring nuclear materials. As a further complication, some of the plants include fuel salt drain tanks intended to provide decay heat removal while others are designed to provide decay heat removal while the salt is maintained within the reactor vessel. Some lessons learned from the prior molten salt breeder reactor program are reflected in all of the new designs. Interior reflectors/shielding are frequently employed to reduce the radiation damage to the reactor vessel, and fuel salt chemistry control is employed to substantially limit oxidizing the container alloy constituents. However, even with the vessel interior shielding, the containment environment around both solid and liquid fueled MSRs during operation is likely to have substantially higher dose rates than at LWRs due to the fission process and fission products in the case of circulating liquid fueled reactors, and the shortlived activation products of fluorine (16N, 20F, and 19O) in the case of FHRs. Consequentially due to insufficient shielding from the coolant and the vessel wall, MSR containments will be remote access only for liquid fueled systems and remote access only during operation for FHRs.

Liquid-fueled Molten Salt Reactors (MSRs) do not contain their fuel in assemblies. It is then not possible to perform traditional item counting and visual accountability of the salt fuel. These facilities are closer to bulk accounting facilities, such as reprocessing plants, and require inventory determinations based on measurements of the actinide content of salts. This can be problematic due to the difficulty of sampling and the destructive analysis of actinide-containing molten salts. Some problems arise from the unique combination of high temperature and high radiation environments present in molten salt fuels. Another challenge is the continuous change in the isotopic concentration of fuel salts due to burn-up, conversion, plating out, and online chemical processing. There is a potential for fuel stocks outside the reactor containment vessel in on-site salt processing. In terms of proliferation resistance of 233U-232Th fuel cycle, the nuclide 232U is an important nuclide in thorium fuel cycle from the standpoint of proliferation resistance, because its daughter Thallium (208Tl) is a strong gamma (2.6 MeV) emitter. The hard gamma ray is not only barrier from to nuclear material theft, but also an effective means of detecting lost fissile material. However, there is a theoretical weakness in obtaining pure 233U at the core of the initial two weeks with a concentration of 232Pu less than 1,000 ppm. Therefore, Pu separation process is one of the most sensitive parts in online reprocessing facility. The decision to use a fertile blanket should also be based on proliferation risk considerations in addition to operational parameters. MSRs can be designed without a separate fertile blanket, which should be considered. In the case of the MSFR, even if fertile blankets are used, the production of 232U is large enough to make difficult the utilization of blankets for proliferation purpose. For the liquid-fueled MSRs without fissile materials separations, many of the observations from the previous section apply, except salt processing is minimized. The reactors will still need some method of estimating total actinide content. These reactor designs reduce proliferation risk for the reactor by not separating any actinides during operation.

Since the commercial operation of Kori unit 1 in 1978, nuclear power has provided cheap, stable and clean electricity in South-Korea. For decades, the discussion about the spent fuel management has been dominated and the government is responsible for on-going research and development (R&D) related to long-term spent nuclear fuel management. The effective management of spent fuel should be applied from the early stage of the R&D process to licensing phases with the step-by-step evaluation system. As part of follow-up efforts after the Fukushima nuclear accident, the Nuclear Promotion Commission and Nuclear Safety Commission were divided in function as an independent agency for enhancing national nuclear safety and security, which aims to protect the public and environment from undue radiological hazard. The national spent fuel project must have a vibrant program for spent fuel management. Due to the nature of these projects, the establishment of a ‘conformity assessment’ system that collects the opinions from the licensing organisations on the results of research projects from the initial R&D stage should be applied advertently in order to efficiently conduct research projects and enhance public confidence. For the government-led project for spent nuclear fuel management, the adequacy and applicability of its technology R&D as well as its sustainability that includes financial, social and environmental performance measures should be evaluated in each stage. The institutionalisation arrangement, so called ‘conformity assessment system’ for the development of a national spent nuclear fuel management plan and related technology should be developed. This study aims to propose the basic principles for the introduction of the conformity assessment system: (1) national management responsibility, (2) spent fuel management project scope, (3) its management main principles, (4) project implementation system, (5) final management project scope and securing financial resources.

The nuclear facilities sites handling radioactive materials are contaminated due to accidents or its activities. Since the experimental reactor was operated in Idaho, USA in 1951, nuclear power and its related activities were carried out in many countries. Thus, the legacy sites in which radioactive materials have been deposited are a matter of public concern. As a result of the operation of facilities related to the use of nuclear energy, it is faced with the restoration of the environment containing radioactive wastes. In particular, the activities carried out in the early years caused its contamination of the sites and areas with significant releases of fission products and natural radioactive wastes adventitiously or intentionally due to the lack of its technology and the unclear radiation risks. In addition, nuclear weapons tests conducted in the 1950s and 1960s and the Chernobyl power plant accident in 1986 caused radioactive contamination in the Pacific Ocean and extensive territories in Europe. Accordingly, the IAEA discussed the restoration of the contaminated areas at the conference on the radiation legacy of the 20th Century in terms of environmental restoration (RADLEG-2000) held at Moscow, Russia in October 2000 and its cases from the former Soviet Union and Eastern Europe were reported. Also, the Nuclear Energy Agency (NEA) has discussed the potential issues on the legacy sites occurring radioactive materials and suggested that these sites should be managed in an open, transparent and consistent manner in order to build sustainable solutions with trust. However, there is currently no overall regulatory system for the management of legacy sites in Korea. The TRIGA Mark-II research reactor, which was commissioned in 1962, was decontaminated and dismantled in 1997. As such, it is necessary to consider the regulatory system related to the existing legacy site. Most of all, the legacy site management and regulatory standards of facilities that have operated in the past and are not currently operating or that deal with natural radioactive materials should be established. Also, the dismantling of NK’s nuclear facilities and management of related radioactive waste, particularly NK’s uranium mines and refining facilities particularly at Pyongsan and Bakcheon in NK are one of the key issue on the North Korea’s denuclearization. In this study, the international standards on the reuse of the legacy site after dismantling are analyzed, and its regulatory considerations used for domestic application are suggested.

The epidemiology of reported food-borne disease (FBD) outbreaks from 2001 to 2008 in Korea and Japan were compared in this study. The outbreak rate of FBD in Japan was significantly higher although the average number of patient in each outbreak in Korea was much higher. In both countries, summer was the season when most FBD outbreaks occurred. The comparison study revealed that FBD outbreaks in spring were more frequent in Korea, and outbreaks in winter were more frequent in Japan. Almost half of FBD outbreaks were observed at restaurants in both countries while FBD outbreaks at schools and work-places in Korea were much higher than in Japan. The most frequent cause of bacterial FBDs in Korea was pathogenic Escherichia coli followed by Salmonella species. On the other hand, Campylobacter jejuni was the most frequent source of bacterial FBDs in Japan. Norovirus, which is related to uncontrolled hand hygiene and involvement of ill food workers, was the main cause of viral FBDs in both countries. In conclusion, there are common epidemiological characteristics as well as several differences in FBD outbreaks of Korea and Japan. These are suggested to be originated from the characteristic of climate, food sources, and life styles in two countries. Establishment of stricter control and surveillance system for FBD outbreaks are required for prevention and reduction of FBD outbreaks in both countries.

미국 9.11 사고 이후 테러는 과거에 비하여 다중이용시설 공격을 통한 불특정 다수의 공격이 증가하고 있다. 연이은 런던 폭탄테러, 파키스탄의 자폭 등은 사람들의 공포심 및 사회적 불안감을 증가시켰다. 최근 국내에서 다양한 국제행사가 개최되고 있어, 방사능테러 위협에 대비한 방사성물질의 국가 안보 의식이 증대되고 있다. 본 논문에서는 HotSpot Code를 사용하여 서로 상이한 기상조건에 따른 결과를 비교하였다. 국내에서 발생 가능한 테러 시나리오 작성 후, RDD(Radiological Dispersal Device) 및 더티밤에 사용될 가능성이 높은 선원을 조사하였다. 기상조건은 Pasquill-Gifford 안정도 등급에 따라 가장 안정된 조건의 F, 가장 불안정한 조건의 A를 선택하여 비교하였다. 시뮬레이션을 통한 A, F 등급 결괏값은 방사선학적 영향에 의해 시민들이 급성 영향으로 사망하는 경우는 없다고 판단하였다. 또한, 풍속 및 기상 안정도에 따라 방사능의 도달 정도가 서로 다르며, 기상 조건에 따라 방사능 희석정도가 서로 다름을 확인할 수 있다. 분석결과는 방사능테러 발생 시 초동 대응에 활용할 수 있을 것으로 예상된다.