An objective of a safety assessment for geological disposal is to evaluate the radiological impact by radionuclides release from radioactive wastes. Computational estimation of all radionuclides transport in the disposal system, however, is not neccessary because some radionuclides has negligible effect on radiological doses. For this reason, prioritization of radionuclides list is preceded before the safety assessment. The Korea Atomic Energy Research Institue (KAERI) has assessed the long-term safety of a disposal system for spent nculear fuels. Currently, thirty eight radionuclides and twenty three elements are considered in the safety assessment activity of the KAERI. Nevertheless, a screening process for radionulides selection has not been articulated yet. In this study, we reviewed radionuclides selection process in forign countries to re-establish screening criteria for the KAERI’s radionuclides list. Screeing models of the Swedish Nuclear Fuel and Waste Management Company (SKB), the Deparment of Eenrgy (US DOE), and the Japan Nuclear Cycle Development Istitute (JNC) were compared. We found that each country developed different screening model depending on scenarios of radionuclides release. Nonetheless, there were common properties that determines the importance of radionuclides. These properties for radionuclides include halflife, radiotoxicity (or specific activity), and mobility in underground medium. Based on the review results, we proposed radionuclides selection process to prioritize the importance of radionucldies in the KAERI safety assessment.

The timescale for the post-closure safety assessment of a deep geological repository ranges from ten thousand to a million year. In such a long period of time, the biosphere inevitably undergoes changes. Therefore, the long-term evolution of a biosphere is recognized as an important issue in the post-closure safety assessment of a deep geological repository for spent fuels. In this study, we reviewed the approaches to address the long-term evolution of a biosphere. The major drivers of longterm evolution of a biosphere are the climate change and the resulting landscape development. They can affect the hydrogeological and hydrogeochemical characteristics of a biosphere, and then the radionuclide migration through the biosphere followed by the exposure doses for the critical groups. In addition, human activities and the social developments can affect the climate change resulting in the long-term evolution of a biosphere. To make a biosphere assessment, the long-term evolution scenarios for the biosphere should be formulated considering these climate change, landscape development, and human activities. In addition, features, events, and processes (FEPs) that affect the long-term evolution of a biosphere should be used. According to the Safety Case reports of Finland, the major long-term evolution scenario drivers of a biosphere are local sea-level change due to climate change and land use related to crop type, irrigation procedures, livestock, forest management, construction of a well, and demographics. The climate change causing the local sea-level change can be simulated using various earth system models such as CLIMBER-2, MPI/UW, and UVic and an icesheet model such as SICOPOLIS. The review results of this study and FEPs related to the climate change, the landscape development, and human activities will be used to formulate long-term evolution scenarios for the safety assessment of a deep geological repository for spent fuels.

In South Korea, the master plan for high-level radioactive waste management, announced in 2016, suggested the construction and operation of intermediate storage facilities on a permanent disposal site and specified the adoption of dry storage in consideration of the ease of operation and expansion. As of 2021, the government is again reviewing its overarching policy on the back-end fuel cycles, including intermediate storage and permanent disposal. In the case of dry storage facilities, safety evaluation is being conducted using a combination of deterministic and probabilistic approaches, similar to that of nuclear power plants. The two methods are complementary, of which Probabilistic Safety Assessment (PSA) has the advantage of being able to identify key scenarios affecting safety, but its use in storage facilities has not been highlighted so far. However, depending on the spent fuel management phases such as loading, transportation, and storage, it may be not enough to capture effective and efficient safety evaluation only deterministically, and probabilistic methods may contribute to the evaluation of long-term operation or external events such as an earthquake. There have already been cases where PSA has been performed on a part of the nuclear fuel cycle through previous studies. This paper created the safety assessment model based on open sources such as the released EPRI reports, by targeting arbitrary intermediate storage facilities. The model considered the scenarios for loading, transportation, and storage, with human error respectively. It will be able to be modified and improved to fit domestic and specific intermediate storage facilities in the future.

KINAC (Korea Institute of Nuclear Non-proliferation and Control) is entrusted with the NSSC (Nuclear Safety And Security Commission) to conduct threat assessments for nuclear facilities. As part of the threat assessment, DBT (Design Basis Threat) must be established every three years, and a threat assessment report must be developed for DBT establishment. This paper suggests a method for collecting and analyzing cyber threat information for the development of a cyber security threat assessment report. Recently, cyber threats not only in the IT (Information Technology) field but also in the ICS (Industrial Control System) field are rapidly increasing. As cyber threats increase, threat information including related attack techniques is also increasing. Although KINAC is conducting a threat assessment on cyber security at nuclear facilities, it cannot collect and analyze all cyber threat information. Therefore, it is necessary to determine a reliable source of threat information for threat assessment, and establish a strategy for collecting and analyzing threat information for DBT establishment. The first method for collecting and analyzing threat information is to first collect threat information on industrial fields with high similarity to nuclear facilities. Most of the disclosed cyber threat information is in the IT field, and most of this information is not suitable for closed-network nuclear facilities. Therefore, it is necessary to first collect and analyze threat information on facilities that use networks similar to nuclear facilities such as energy and financial sector. The second method is to analyze the attack technique for the collected threat information. The biggest factor in DBT reset is whether there is a new threat and how much it has increased compared to the existing threat. Therefore, it is necessary to analyze which attack technique was used in the collected threat information, and as part of the analysis, a cyber attack analysis model such as a kill chain can be used. The last method is to collect and manage the disclosed vulnerability information. In order to manage vulnerabilities, it is necessary to analyze what assets are in the nuclear facility first. By matching the reported vulnerability with the CDA (Critical Digital Asset) in the facility, it is possible to analyze whether the CDA can be affected by a cyber attack.As cyber threats continue to increase, it is necessary to analyze threat cases of similar facilities, attack techniques using attack models, and vulnerability analysis through asset identification in order to develop a threat assessments report.

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.

Efforts for nuclear non-proliferation have continued since the development of nuclear weapons and the conclusion of the NPT Treaty. Nuclear proliferation requires materials, facilities, and human resources to make nuclear weapons, and it takes a medium to long-term time. There are many restrictions in the current system to obtain nuclear materials and facilities, so it is often done through illegal means, black markets, or confidential transactions. Methods have been developed to evaluate the nuclear non-proliferation regime to strengthen the non-proliferation and solve the problems. The IAEA and the United States DOE initiated the proliferation resistance evaluation in 1980. The DOE conducted the assessment in three main evaluation categories: materials, technical characteristics of facilities, and institutional barriers. In another nuclear non-proliferation evaluation study, some researchers evaluated three main types: current capacity, political situation, and international situation. Detailed indicators include economic capacity, industrial capacity, nuclear capacity, leader’s intentions, political structure, competitive relations, alliances, and international norms. Most of these evaluations are based on the situation at the time of assessment at the national level. Historical examples of nuclear proliferation are rare, and verification is also challenging. The Bayesian probability is widely used when the data is small, experiments are impossible, and the causal relationship is unclear. A Bayesian network is a combination of Bayesian probability and graphics. It is used throughout the industry because it can easily derive results according to causal relationships and weights of various variables, evaluate the risk for decision-making, and obtain changed results through data updates. In particular, to evaluate the proliferation of nuclear weapons, Freeman developed the Freeman network in 2008 and the Freeman-Mella network in 2014. Freeman explained in detail only the process of deriving variables, correlations, and probabilities of factors related to factors such as motivation, intention, and resources. It isn’t easy to view as an objective result value because it does not describe the academic background for path selection, motivation list, intention, and resource variable selection. However, the research was meaningful because he first used the Bayesian network for nuclear proliferation. Although some studies have been done at the macro level, there is no case of applying it in export controls, which is the beginning of the actual spread. Also, there is no quantitative value for factors for risk assessment. There is little data, and verification of causality is difficult, so if the Bayesian network is applied to export control and applied to actual implementation, it will help make decisions such as export license or export denial.

최근 해상풍력발전단지 등의 구조물 설치를 추진하는 사업이 증가하고 있는 추세이며, 이러한 해상장해물의 설치는 인근 해역 을 통항하는 선박에게 영향을 미칠 수 있다. 이에 본 연구는 통항로 내 장해물에 따라 통항하는 선박에게 주는 위험도를 정량적으로 평가 하는 것이 목적이다. 이를 위해 위험도에 영향을 미치는 파라미터를 선정하고, 파라미터를 기반으로 시나리오를 설정하였다. 본 연구는 위험도 평가 모델인 ES 모델을 통해 시나리오 평가를 실시하였으며, 장해물의 크기가 커지고, 장해물과의 이격거리가 커지고, 통항 속력 이 느리고, 통항량이 증가할수록 위험 비율이 높아짐을 확인하였다. 또한, 교통흐름 방향이 지정된 경우에 일반적인 교통흐름에 비해 낮 은 위험 비율을 보임을 파악하였다. 본 연구는 수행된 시나리오 결과를 기반으로 일반화 모형을 제시하여 다대포 해상풍력발전단지에 적 용하였으며, 일반화 모형을 통해 대략적인 위험 비율을 추정하는 것이 가능함을 나타냈다. 본 연구에서 제시된 일반화 모형은 해상장해물 설치에 있어 사전 참고자료로 활용될 수 있을 것으로 판단된다.

지난 10여년간 성범죄자 재범위험성 평가는 학문적으로나 실무적으로 많은 발전을 이루어 왔다. 이러한 비약적 발전에도 불구하고, 선행연구들은 재범위험성 평가도구의 한계 중 하나로 범죄자 유형론에 관한 고려가 부족하다는 점을 지적하고 있다. 본 연 구는 이러한 주장의 타당성을 검증하는 것을 목표로 한다. 이를 위해‘한국형 성범죄자 재범위험성 평가도구(KSORAS: Korean Sex Offender Risk Assessment Scale)’ 를 활용하여, KSORAS가 아동/청소년 상대 성범죄자와 성인 상대 성범죄자의 재범위 험성을 적절히 예측하는지를 검증했다. 본 연구문제에 답하기 위해 전자감독명령이 부과된 성폭력사범 866명의 재범상황을 추적했다. 데이터 분석결과, KSORAS는 아 동/청소년 상대 성범죄자의 재범은 잘 예측함에 반해, 성인 상대 성범죄자의 재범은 상대적으로 잘 예측하지 못했다. 두 집단의 재범을 예측하는 문항들도 상이한 패턴을 보였다. 연구의 후반부에서는 성범죄자 유형론의 주장을 고려하여, 아동/청소년 상대 성범죄자 평가도구(KSORAS-MINOR)와 성인 상대 성범죄자 재범위험성 평가도구 (KSORAS-ADULT)를 각각 구성하고 그 예측타당도를 분석하였다. 분석 결과, 성범 죄자 유형론을 고려하지 않은 기존의 접근법에 비해, 기존 도구를 수정 개발한 성범죄 자 유형별 평가도구의 예측타당도는 통계적으로 유의미한 수준까지 향상되었다. 이러 한 결과를 바탕으로 향후 성범죄자 평가와 관련된 정책방향 및 후속연구의 제안점을 논의하였다.

The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

Mercury and its compounds are globally managed chemicals as risks to the human body and ecosystem. It mainly enters the human body through ingestion of seafood, especially, methylmercury causes serious diseases such as central nervous system (CNS) disorder and renal dysfunction. In this study, total mercury (Hg) and methyl mercury (MeHg) were determined in seafood (16 species, n = 97) commonly consumed in Daejeon, using a gold amalgamation method. The average concentration (Hg/MeHg mean ± S.D. (minimum–maximun) mg/kg) of total Hg and MeHg in the samples was as follows; Fish 0.038 ± 0.058 (0.004 – 0.272) / 0.028 ± 0.047 (N.D. – 0.236), Crustacea 0.023 ± 0.021 (0.003 – 0.078) / 0.016 ± 0.018 (N.D. – 0.055), Mollusks 0.015 ± 0.015 (0.002 – 0.056) / 0.008 ± 0.013 (N.D. – 0.040). The concentration of MeHg in seafood were significantly correlated with total Hg concentration (p<0.001). The species with the highest average concentration of Hg was the Korean rockfish, but there was no sample that exceeded the maximum residual limit. The total %provisional tolerable weekly intake (%PTWI) value of MeHg for all of the samples was 3.76%, compared with the JECFA’s reference value, which indicates that there is almost no health risk from heavy MeHg intake through the consumption of seafood distributed in Daejeon.

Vegetation is the basis for biodiversity conservation and sustainable development. In the Environmental Impact Assessment (EIA), which is the most direct and efficient policy measure to prevent degradation of nature, vegetation-related assessment has limitations as it is not based on quantitative and scientific methods. In addition, it focuses on the presence of protected species; hence, it does not take into account the role of vegetation as a habitat on a wide-area scale. As a way to overcome these limitations, this study aims to contribute to the quantification and advancement of future EIA on vegetation. Through the review of previous studies, core areas, connectivity, and vegetation condition were derived as the items to be dealt within the macroscopic aspect of vegetation impact assessment. Each item was spatially constructed using land cover maps and satellite imageries, and time series change analysis was performed. As a result, it was found that vegetation has been continuously deteriorating due to development in all aspects, and in particular, development adversely affects not only the inside of the project site but also the surrounding area. Although this study suggested the direction for improvement of the EIA in the vegetation sector based on data analysis, a more specific methodology needs to be established in order to apply it to the actual EIA process. By actively utilizing various environmental spatial data, the impact of the development on the natural ecosystem can be minimized.

An estuary is an area where a freshwater river or stream meets the ocean. Even before the importance of the value of estuaries was recognized, the estuary was lost because of large-scale conversion by draining, filling, damming, and dredging. In South Korea, 643 estuaries are located, and the total area is 3,248,300 ha, accounting for 32.5% of the total area of South Korea. Over 35% of Korean estuaries are closed estuaries which are only temporally connected with the sea, either permanently or periodically. Since 2008, in order to preserve the estuary ecosystem and solve major issues in the estuary by accumulating knowledge about the estuarine ecosystem, the Ministry of Environment of Republic of Korea has been conducting the “Estuarine Ecosystem Monitoring and Assessment Project”. At 668 sites of 325 estuaries, epilithic diatom, benthic macroinvertebrate, fish, and vegetation are investigated, and the habitat condition of each site is evaluated using the newly developed biotic index. More than 100 researchers annually record 2,097 species of estuaries according to the standardized survey guidelines over the past 14 years and provide strictly managed data necessary for establishing estuaries conservation policies. As a result of bibliometric analysis of 1,195 research articles related to the monitoring and assessment of the estuarine ecosystem, research on pollutants such as heavy metals and sediment control have recently been conducted. “Estuarine Ecosystem Monitoring and Assessment Project” is an ecological monitoring type of long-term mandated monitoring that is usually focused on identifying trends. Although it is difficult to identify the mechanism influencing a change in an ecosystem through long-term mandated monitoring, providing empirical data for supporting evidence-based policy, decision-making, and the management of ecosystems. In order to increase the efficiency of the project, research to investigate the relationship between sediments and pollutants and organisms can be conducted at specific estuaries or sites to compensate for the shortcomings of mandatory monitoring.

본 연구에서는 폐기물 배출해역의 퇴적물이 해양생물에 미치는 영향을 평가하기 위해 2016~2019년 3개 배출해역; 동해병, 서해 병, 동해정 해역의 9개 정점에서 채취한 퇴적물 시료들을 대상으로 국내 해양폐기물공정시험기준에 의거하여 저서성단각류(Monocorophium acherusicum)와 발광박테리아(Vibrio fischeri)를 이용한 독성시험을 수행하였다. 시험결과, 상대평균생존율(저서성단각류)과 상대발광저해율 (발광박테리아)이 각각 30 % 이하로서 ‘독성없음’으로 판정되었으나, t검정을 이용한 독성 평가 결과에서는 총 12개(2016년 6개, 2017년 1개, 2018년 1개, 2019년 4개)의 저서성단각류 시료에서 대조구와 유의한 차이를 나타내었다(p<0.05). 저서성단각류의 독성원인 탐색을 위해 퇴 적물 내 8종 중금속 함량(Cr, As, Ni, Cd, Cu, Pb, Zn, Hg)과 저서성단각류 상대평균생존율의 단순선형회귀분석을 수행한 결과, Cr의 저서성 단각류 독성 기여도가 가장 높았다(p=0.000, R2=0.355). 또한, 매년 독성영향이 가장 높은 정점(DB-85)의 시료에서 Cr이 여전히 가장 높은 농 도로 검출되었으며, 해양환경기준을 매년 초과하였다. 해양폐기물공정시험기준의 생태독성판정 기준 적용 시 ‘독성없음’으로 평가되는 퇴 적물 오염도가 대조구와의 통계적 유의성 검정, 독성원인확인 평가를 적용할 경우 독성영향을 수용 가능한 수준으로 판단하기 어려우므로 향후 종민감도분포곡선을 활용한 정량적 위해성 평가를 통한 준거치를 도출하여 생태독성 영향 판단 기준의 재설정을 고려할 필요가 있다.

The severity of acute pancreatitis (AP) is classified into mild, moderately severe, and severe, considering the presence and duration of organ failure and local complications. Since patients with AP show a large difference in mortality and morbidity according to AP severity, evaluation of the severity of patients with AP in the early stage is important for predicting the prognosis and determining treatment plans including transfer to the intensive care unit or advanced facilities. In order to evaluate the initial severity of AP, it is necessary to confirm the presence of organ failure and objective evaluation using imaging or clinical examinations. In this guideline, it is recommended that evaluation using various severity indices such as bedside index for severity in acute pancreatitis (BISAP), systemic inflammatory response syndrome (SIRS), and acute physiology and chronic health evaluation (APACHE)-II scores be considered.

The aims of this study were to measure the ultrasonographic biometry of genitalia of the indigenous rams and observe the relationship of biometry on semen parameters. The epididymal volume was significantly reduced (p < 0.01) after semen collection compared with before collection for both left and right part in all rams. The cumulative results showed that although there was no significant difference in length, width and volume of epididymis between before and after semen collection, however the values were lower after collection. The epididymal length was significantly correlated with epididymal volume (p < 0.01), semen motility (p < 0.05) and semen morphology (p < 0.01). Epididymal width was only significantly correlated with epididymal volume (p < 0.01) not with the semen parameters. Epididymal volume had a significant correlation only with semen morphology (p < 0.01).The scrotal circumference had the significant correlation with semen density, mass activity, concentration and motility (p < 0.01). The epididymis had the similar or slightly increased echogenicity as compared to the normal testis. During whole study, some white spots were found on testis which did not affect the semen quantity and quality. Significant variation was observed only for semen concentration and motility among the rams (p < 0.05). The overall normal morphology was 90.5 ± 4.6% with highest percentage of coiled tail abnormalities.