Wolsong Unit 1, a domestic heavy water reactor nuclear power plant, was permanently shut down in December 2019. Accordingly, Wolsong Unit 1 plans to prepare a Final Decommissioning Plan (FDP), submit it to the government by 2024, receive approval for decommissioning, and begin full-scale decommissioning. One of the important tasks in the decommissioning of Wolsong Unit 1 is to determine the decommissioning strategy. It is necessary to decide on a decommissioning strategy considering various factors and variables, secure the technical background, and justify it. The selection of a decommissioning strategy is best achieved through the use of formal decisionmaking assistance techniques, such as considerations related to influencing factors. It is very important to understand the basic decommissioning strategy alternatives and whether sufficient consideration has been given to situations where only a single unit is permanently shut down in a multi-unit site like Wolsong Unit 1, while the remaining units are in normal operation. As a process for selecting a decommissioning strategy, first, all considerations that could potentially affect decommissioning presented in the KINS Decommissioning Safety Review Guidelines were synthesized, influencing factors to be used in the decision-making process were determined, and the concept was defined. In order to select the most appropriate decommissioning strategy by considering various evaluation attributes of possible decommissioning alternatives (immediate dismantling and delayed dismantling), the Wolsong Unit 1 decommissioning strategy was evaluated by reflecting the AHP decision-making technique.

The domestic Pressurized Heavy Water Reactor (PWHR) nuclear power plant, Wolsong Unit 1, was permanently shut down on December 24, 2019. However, research on decommissioning has mainly focused on Pressurized Water Reactors (PWRs), with a notable absence of both domestic and international experience in the decommissioning of PHWRs. If proper business management such as radiation safety and waste is not performed, it can lead to increased business risks and costs in decommissioning. Therefore, the assessment of waste volume and cost, which provide fundamental data for the nuclear decommissioning process, is a crucial technical requirement before initiating the actual decommissioning of Wolsong Unit 1. Decommissioning radiation-contaminated structures and facilities presents significant challenges due to high radiation levels, making it difficult for workers to access these areas. Therefore, technology development should precede decommissioning process assessments and safety evaluations, facilitating the derivation of optimal decommissioning procedures and ensuring worker safety while enhancing the efficiency of decommissioning operations. In this study, we have developed a program to estimate decommissioning waste amounts for PHWRs, building upon prior research on PWR decommissioning projects while accounting for the specific design characteristics of PHWRs. To evaluate the amount of radioactive waste generated during decommissioning, we considered the characteristics of radioactive waste, disposal methods, packaging container specifications, and the criteria for the transfer of radioactive waste to disposal operators. Based on the derived algorithm, we conducted a detailed design and implemented the program. The proposed program is based on 3D modeling of the decommissioning components and the calculation of the Work Difficulty Factor (WDF), which is used to determine the time weighting factors for each task. Program users can select the cutting and packaging conditions for decommissioning components, estimate waste amount based on the chosen decommissioning method, and calculate costs using time weighting factors. It can be applied not only to PHWRs, but also to PWRs and non-nuclear fields, providing a flexible tool for optimizing decommissioning process.

After the major radioactivation structures (RPV, Core, SG, etc.) due to neutron irradiation from the nuclear fuel in the reactor are permanently shut down, numerous nuclides that emit alpha-rays, beta-rays, gamma-rays, etc. exist within the radioactive structures. In this study, nuclides were selected to evaluate the source term for worker exposure management (external exposure) at the time of decommissioning. The selection of nuclides was derived by sequentially considering the four steps. In the first stage, the classification of isotopes of major nuclides generated from the radiation of fission products, neutron-radiated products, coolant-induced corrosion products, and other impurities was considered as a step to select evaluation nuclides in major primary system structures. As a second step, in order to select the major radionuclides to be considered at the time of decommissioning, it is necessary to select the nuclides considering their half-life. Considering this, nuclides that were less than 5 years after permanent suspension were excluded. As a third step, since the purpose of reducing worker exposure during decommissioning is significant, nuclides that emit gamma rays when decaying were selected. As a final step, it is a material made by radiation from the fuel rod of the reactor and is often a fission product found in the event of a Severe accident at a nuclear power plant, and is excluded from the nuclide for evaluation at the time of decommissioning is excluded. The final selected Co-60 is a nuclide that emits high-energy gamma rays and was classified as a major nuclide that affects the reduction of radiation exposure to decommissioning workers. In the future, based on the nuclide selection results derived from this study, we plan to study the evaluation of worker radiation exposure from crud to decommissioning workers by deriving evaluation results of crud and radioactive source terms within the reactor core.

The development of separation method of radioactive tritium is imperative for treating tritiumcontaminated water originating from nuclear facilities. Polymer electrolyte membrane electrolysis technology represents a promising alternative to conventional alkaline electrolysis for tritium enrichment. Nevertheless, there has been limited research conducted thus far on the composition of membrane electrode assemblies (MEAs) specifically optimized for tritium separation, as well as the methods used for their fabrication. In this study, we conducted an investigation aimed at optimizing MEAs specifically tailored for tritium separation. Our approach involved the systematic variation of MEA components, including the anode, cathode, porous transport layer, and electrode formation method. The water electrolysis efficiency and the H/D separation factor in deuterated water (1%) were evaluated with respect to both the preparation method and the composition of the MEA. To assess the long-term stability of the MEAs, changes in cell voltage, resistance, and the active electrode area were analyzed using impedance analysis and cyclic voltammetry. Furthermore, we examined H/D separation factor both before and after degradation. The results showed that MEAs with different anode/cathode configurations and electrode formation methods improved the electrolysis efficiency compared to commercial MEAs. In addition, the degree of change in the resistance value was also different depending on the electrode formation method, indicating that the electrode formation method has a significant impact on the stability of the electrolysis system. Therefore, the study showed that the efficiency and long-term stability of the water electrolzer can be improved by optimizing the MEA fabrication method.

The radiological characterization of SSCs (Structure, Systems and Components) plays one of the most important role for the decommissioning of KORI Unit-1 during the preparation periods. Generally, a regulatory body and laws relating to the decommissioning focus on the separation and appropriate disposal or storage of radiological waste including ILW (intermediate level waste), LLW (low level waste), VLLW (very low level waste) and CW (clearance waste), aligned with their contamination characteristics. The result of the preliminary radiological characterization of KORI Unit-1 indicated that, apart from neutron activated the RV (reactor vessel), RVI (reactor vessel internals), and BS (biological shielding concrete), the majorities of contamination were sorted to be less than LLW. Radiological contamination can be evaluated into two methods. Due to the difficulties of directly measuring contamination on the interior surfaces of the pipe, called CRUD, the assessment was implemented by modeling method, that is measuring contamination on the exterior surfaces of the pipes and calculating relative factors such as thickness and size. This indirect method may be affected by the surrounding radiation distribution, and only a few gamma nuclides can be measured. Therefore, it has limitation in terms of providing detailed nuclide information. Especially, α and β nuclides can only be estimated roughly by scaling factors, comparing their relative ratios with the existing gamma results. To overcome the limitation of indirect measurement, a destructive sampling method has been employed to assess the contamination of the systems and component. Samples are physically taken some parts of the systems or components and subsequently analyzed in the laboratory to evaluate detailed nuclides and total contamination. For the characterization of KORI Unit-1, we conducted the radiation measurement on the exterior surfaces of components using portable instruments (Eberline E-600 SPA3, Thermo G20-10, Thermo G10, Thermo FH40TG) at BR (boron recycle system) and SP (containment spray system) in primary system. Based on these results, the ProUCL program was employed to determine the destructive sample collection quantities based on statistical approach. The total of 5 and 8 destructive sample quantities were decided by program and successfully collected from the BR and SP systems, respectively. Samples were moved to laboratory and analyzed for the detail nuclide characteristics. The outcomes of this study are expected to serve as valuable information for estimating the types and quantities of radiological waste generated by decommissioning of KORI Unit-1.

Domestic commercial low- and intermediate-level radioactive waste storage containers are manufactured using 1.2 mm thick cold-rolled steel sheets, and the outer surface is coated with a thin layer of primer of 10~36 μm. However, the outer surface of the primer of the container may be damaged due to physical friction, such as acceleration, resonance, and vibration during transportation. As a result, exposed steel surfaces undergo accelerated corrosion, reducing the overall durability of the container. The integrity of storage containers is directly related to the safety of workers. Therefore, the development of storage containers with enhanced durability is necessary. This paper provides an analysis of mechanical properties related to the durability of WC (tungsten carbide)-based coating materials for developing low- and intermediate-level radioactive waste storage containers. Three different WC-based coating specimens with varied composition ratios were prepared using HVOF (high-velocity oxy-fuel) technique. These different specimens (namely WC-85, WC-73, and WC-66) were uniformly deposited on cold-rolled steel surfaces ensuring a constant thickness of 250 μm. In this work, the mechanical properties of the three different WCbased coaitng materials evaluated from the viewpoints of microstructure, hardness, adheision force between substrate and coating material, and wear resistance. The cross-sectional SEM-EDS (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) images revealed that elements W (tungsten), C (carbon), Ni (nickel), and Cr (chromium) were uniformly distributed within the each coating layers which was approximately 250 μm thick. The average hardness values of HWC-85 and HWC-73 were found to be 1,091 Hv (Vickers Hardness) and 1,083 Hv, respectively, while the HWC-66 exhibited relatively lower hardness value of 883 Hv. This indicates that a higher WC content results in increased hardness. Adhesion force between and substrates and coating materials exceeded 60 MPa for all specimens, however, there were no significant differences observed based on the tungsten carbide content. Furthermore, a taber-type abrasion tester was used for conducting abrasion resistance tests under specific conditions including an H-18 load weight at 1,000 g with rotational speed set at 60 RPM. The abrasion resistance tests were performed under ambient temperatures (RT: 23±2°C) as well as relative humidity levels (RH: 50±10%). Currently, the ongoing abrasion resistance tests will include some results in this study.

This study focuses on the development of coatings designed for storage containers used in the management of radioactive waste. The primary objective is to enhance the shielding performance of these containers against either gamma or neutron radiation. Shielding against these types of radiation is essential to ensure the safety of personnel and the environment. In this study, tungsten and boron cabide coating specimens were manufactured using the HVOF (High-Velocity Oxy Fuel) technuqe. These coatings act as an additional layer of protection for the storage containers, effectively absorbing and attenuating gamma and neutron radiation. The fabricated tungsten and boron carbide coating specimens were evaluated using two different testing methods. The first experiment evaluates the effectiveness of a radiation shielding coating on cold-rolled steel surfaces, achieved by applying a mixture of WC (Tungsten Carbide) powders. WC-based coating specimens, featuring different ratios, were prepared and preliminarily assessed for their radiation shielding capabilities. In the gamma-ray shielding test, Cs-137 was utilized as the radiation source. The coating thickness remained constant at 250 μm. Based on the test results, the attenuation ratio and shielding rate for each coated specimen were calculated. It was observed that the gammaray shielding rate exhibited relatively higher shielding performance as the WC content increased. This observation aligns with our findings from the gamma-ray shielding test and underscores the potential benefits of increasing the tungsten content in the coating. In the second experiment, a neutron shielding material was created by applying a 100 μm-thick layer of B4C (Boron Carbide) onto 316SS. The thermal neutron (AmBe) shielding test results demonstrated an approximate shielding rate of 27%. The thermal neutron shielding rate was confirmed to exceed 99.9% in the 1.5 cm thick SiC+B4C bulk plate. This indicates a significant reduction in required volume. This study establishes that these coatings enhance the gamma-ray and neutron shielding effectiveness of storage containers designed for managing radioactive waste. In the future, we plan to conduct a comparative evaluation of the radiation shielding properties to optimize the coating conditions and ensure optimal shielding effectiveness.

Graphene-based sensors have emerged as significant tools for biosensing applications due to their unique electrical, mechanical, and thermal properties. In this study, we have developed an innovative and sensitive aptasensor based on the surfacemodified graphene for the detection of lung cancer biomarker CA125. The sensor leverages the combination of graphene surface and gold nanoparticles (AuNPs) electrodeposition to achieve a high level of sensitivity and selectivity for the biomarker detection. A noticeable decrease in electron transfer resistance was observed upon the AuNPs deposition, demonstrating the enhancement of electrochemical performance. Our experimental findings showed a strong linear relationship between the sensor response and CA125 concentrations, ranging from 0.2 to 15.0 ng/mL, with a detection limit of 0.085 ng/ mL. This study presents a novel approach to lung cancer detection, surpassing the traditional methods in terms of invasiveness, cost, and accuracy. The results from this work could pave the way for the development of graphene-based sensors in various other biosensing applications.

본 연구는 주변 환경의 차이에 따른 화분매개곤충의 유입 특성을 파악하기 위하여 국립수목원 내 진화속을걷 는정원과 부추속전문전시원에 식재된 울릉산마늘의 화분매개곤충을 조사하였다. 2023년 5월 22일부터 6월 2일 까지 꽃이 70% 이상 개화하였을 때 포충망을 활용하여 8일간 곤충을 채집하였고, 각 전시원 별 식생(피도), 기후 (온도·습도·조도)를 조사하였다. 조사 결과 진화속을걷는정원에서 피도 60% 온도 26.4℃, 습도 31.5%, 조도 40953.6lx, 화분매개곤충 20과 450개체, 부추속전문전시원은 피도 90%, 온도 25.6℃, 습도 31.6%, 조도 6387lx, 화분매개곤충 15과 196개체로 나타났다. 온도와 조도가 상대적으로 높은 진화속을걷는정원이 채집된 곤충의 다양성과 방문 빈도가 높았다. 시간대별 곤충의 방문 빈도를 비교해본 결과 온도와 조도는 개체수가 증가할 때 같이 증가하는 경향을 보였으며, 습도는 반대의 경향을 보였다.

왕담배나방은 기주범위가 넓은 다식성으로 토마토, 옥수수, 담배, 해바라기, 땅콩, 면화, 콩 등 다양한 작물에 피해를 주는 해충이며, 장거리 이동성 해충으로도 유명하다. 본 연구에서는 기존 자료를 바탕으로 월동번데기의 성충으로 우화모델(2종)를 작성하고 포장 실측자료와 비교하여 평가하였다. 월동 번데기는 휴면을 종료한 후 안점소실 과정을 거쳐 정상의 번데기로 이행되고 비로소 성충으로 우화하는 것으로 가정하였다. 첫 번째 모형(모 형 1)은 2단계 휴면후발육 우화모형으로 안점소실에 필요한 적산온도 59.9DD (발육영점온도 15.9℃)와 번데기 발육완료에 필요한 192.3DD (발육영점온도 10.2℃)로 구성하였다. 두 번째 모형(모형 2)은 온도자극 우화모형으 로 17.63℃의 온도자극 이후에 번데기 발육을 개시하는 모형이었다. 적산온도는 단순 평균온도법과 사인곡선법 으로 계산하여 비교하였다. 포장자료와 비교 결과 모형 1에 사인곡선법을 적용했을 때 실측치와 편차가 3일보다 작거나 차이가 없었다. 반면 사인곡선법을 적용한 모형 2는 3~6.5일의 편차가 있었다. 평균온도법을 적용한 경우 두 모형 모두 실측치와 편차가 증가하였다. 모형을 활용하여 예측 우화시기와 트랩유살자료를 비교하여 왕담배 나방의 비래 가능성에 대하여 고찰하였다.

최근 친환경 노지 감귤원을 중심으로 알락하늘소 피해가 증가하고 있지만 효과적인 예찰 방법이 없는 실정이 다. 본 연구에서는 알락하늘소 성충 예찰을 위하여 카이로몬을 선발하였고, 알락하늘소가 다발생(>100마리)한 과원 3개소에서 유인력을 평가하였다. 시험 결과, 집합페로몬 단독처리 시 알락하늘소 암컷 성충에 대한 유인효 과를 확인할 수 있었지만 소수 개체만 유인이 되었고, 카이로몬(Kairomone) 단독 처리 시 알락하늘소 성충 포획 수가 증가하는 것을 확인할 수 있었다. 집합페로몬과 카이로몬을 동시 처리 시 알락하늘소가 대량으로 유인되는 것을 확인할 수 있었다. 이는 알락하늘소가 종내신호물질(집합페로몬)을 인지할 때 서식지로서 적합한지 판단 의 기준으로 기주식물의 존재여부를 동시에 확인하기 떄문인 것으로 판단된다.

표면발현(surface-display system)은 세포 또는 바이러스 표면에 목적 단백질을 고정하여 발현시킴으로써 목적 단백질에 대하여 독립적인 공간 구조 및 생물학적 활성을 부여하는 단백질 공학 기술이다. 또한 이를 이용하여 높은 중화항체 유도 및 대량생산이 가능한 삼량체의 형태로 항원 단백질의 발현 또한 가능하다. BES(baculovirus expression system)에서의 표면발현 기술은 번역 후 수정과정 및 복잡한 구조의 다양한 단백질의 발현이 가능하기 에 다른 숙주 기반 시스템보다 효율적이라고 보고되고 있다. 그러나 목적 단백질 외의 다른 표면 단백질과 발현 공간에서의 경쟁으로 목적 단백질의 낮은 생산량이 큰 문제점으로 지적되고 있다. 따라서, 이러한 BES에서 표면 발현의 생산 효율을 증대시키기 위하여, 동일한 표면 공간에 대한 단백질 간의 발현 경쟁에 대해 실험적으로 확인 후, 그를 해결하기 위하여 표면발현에 최적인 목적 단백질 발현을 위한 프로모터 선발 실험을 수행하였다. 이를 통해 BES에서 표면발현에 의한 목적 단백질의 생산 효율을 증대시킬 수 있음을 확인하였다.

The genus Hilara is one of the largest group in the family Empididae. It is usually found on the water surface, banks of rivers, streams, lakes or ponds and damp forests. The genus Hilara was established by Meigen in 1822, based on the type species Hilara maura (Fabricius, 1776). In this study, the genus Hilara is reported for the first time in Korea. A total of 6 species was recognozed in korea. Amog them, 3 new species of the genus Hilara Meigen: Hilara sp. nov. 1, Hilara sp. nov. 2 and Hilara sp. nov. 3 Hilara sp. nov. 4 and Hilara sp. nov. 5 are described as new to science. Also, one species, Hilara echinata Frey, is reported for the first time from korea. Adults and genitalia were examined and illustrated with a key to the genus Hilara in Korea and DNA barcodes, when available.

기존에는 생산되는 키틴과 키토산의 대부분이 게, 새우등 갑각류 껍질에서 유래하였다. 하지만 어업에 의존하 는 기존 갑각류 비해 친환경적이며 품질 유지에 이점을 가지는 곤충으로부터 유래한 키틴이 최근 주목 받기 시작 하며 연구가 활발해지고 있다. 이에 키토산이 남조류의 응집을 통해 녹조 제거 효과를 가지며 기존에 녹조를 억제하기 위해 널리 사용되던 살조제들이 독성을 띠어 환경에 악영향을 미치는 문제를 해결할 수 있다는 연구를 참고하여 매미 탈피각으로부터 추출한 키토산을 녹조 방제에 활용해 보고자 하였다. 매미 탈피각으로부터 키토 산을 추출하고 대표적인 녹조 원인종인 Microcystis aeruginosa 배양 후 추출한 키토산을 처리하여 녹조의 응집 효과를 관찰하였다. 본 연구에서 새로운 키토산 추출 원으로서 매미 탈피각의 가능성을 제시하였으며 이를 녹조 방제에 활용함으로써 버려지는 자원인 매미 탈피각의 활용 방안을 제시하였다.

Corn silage is extensively utilized in ruminant feeding on a global scale, with substantial research efforts directed towards enhancing its nutritional worth and managing moisture content. The purpose of this study was to assess the impact of normal cutting height and elevated cutting height on whole-crop corn silage. Corn was harvested at heights of 15 cm and 45 cm above the ground, respectively, 45 days after heading. The harvested corn was cut into 2-3 cm lengths and packed into 20-liter plastic silos in triplicate. The results showed that dry matter (DM), crude protein (CP), water soluble carbohydrates (WSC), and in vitro dry matter digestibility (IVDMD) of C45 were significantly higher than those of the control, while the neutral detergent fiber (NDF) was significantly lower in C45 (p<0.05). The C15 had higher yields than C45 (p<0.05). There was no significant difference in the total digestible nutrients (TDN) yield of whole-crop corn silage. The increase in cutting height resulted in a larger change in moisture content and NDF per centimeter. After 60 days-ensiling, C45 showed significantly lower NH3-N concentrations. Moreover, C45 had significantly higher lactic acid concentration, lactic acid/acetic acid ratio, and lactic acid bacteria count compared to the control. Mold was not detected and the yeast count was less than 2 log10 cfu/g fresh matter in both control and C45. In summary, C45 improved the feeding value and fermentation quality of whole-crop corn silage at the expense of forage productivity.

The COVID-19 pandemic has adversely affected the overall economic growth of countries. Governments have taken various measures to prevent the spread of the virus, resulting in a significant increase in unemployment, such as young people who are disadvantaged groups such as first-time job seekers and inexperienced fresh graduates. The concept of sustainable development has been gradually recognized by most countries as an important principle in international regulations. It has been reflected in international treaties, judicial cases, and initiatives. To alleviate the pressure of youth unemployment, China has adopted a series of policies and measures, which are consistent with the concept of sustainable development. This paper intends to focus on the current situation of China’s youth employment market and relevant laws and policies to improve it. It draws on the measures taken by other countries to deal with youth unemployment and puts forward suggestions from the perspective of sustainable development.

단단한 자구를 가진 적색 비모란선인장 ‘Gangjeok’ 품종 은 ‘Isaek’품종을 모본으로, ‘Suyeon’ 품종을 부본으로 하여 2018년에 교배하여 육성하였다. 교배 후 획득한 종자는 조직 배양실에서 기내파종하여 획득한 유묘를 기내에서 삼각주선 인장에 접목하여 ‘1802001’ 등 20계통을 양성하였다. 2019 년에 기내에서 양성한 20계통을 온실에서 삼각주선인장 대목 에 접목하여 재배하면서 ‘1812005’ 계통을 1차 선발하였다. 2020년부터 2022년까지 3차에 걸쳐서 특성을 검정한 후, 농 산물직무육성품종 심의회에서 최종 선발하여 ‘Gangjeok’으 로 명명하였다.‘Gangjeok’ 품종은 편원형의 적색 구를 가진 다. 혹(tubercle)이 돌출된 형태의 모구는 8.4개의 능(rip)을 가지며, 3.5mm 짧은 회색 가시가 발생한다. 정식 10개월 후 ‘Gangjeok’ 품종의 직경은 46.1mm이며, 자구는 평균 18.3 개 발생한다. 2022년 육성계통 평가회에서 ‘Gangjeok’ 품종 은 높은 기호도 점수 4.0을 받았다.

주방세제의 진딧물 살충효과와 분국화 생육에 미치는 영향 을 알아보기 위해 실험을 수행하였다. 복숭아혹진딧물과 목화 진딧물을 대상으로 주방세제 100, 200, 400배액 단용처리와 주방세제 400배액 100mL에 소주 10mL 또는 20mL를 혼용 하여 분무 처리하였다. 그 결과 주방세제 400배 이하의 모든 농도에서 복숭아혹진딧물은 85%, 목화진딧물은 90%의 살충 률을 보였다. 주방세제와 소주 혼용처리에 의한 살충효과 상 승은 보이지 않았다. 하우스안에서 진딧물이 많이 발생한 분 국화 잎에 400배액 이하의 농도로 3일 간격으로 2회 처리함 으로써 90% 이상의 진딧물이 감소되는 효과를 얻을 수 있었 다. 또한 분국화를 재배하면서 3~4일 간격으로 5주간 지속적 으로 주방세제를 처리했을 때, 대조구에서는 90% 잎에서 진 딧물이 발생한데 비해, 모든 주방세제 단독 처리구에서는 발 생율이 15% 이하로 낮게 유지되었다. 또한 국화의 생체중, 초 장, 엽수는 주방세제 농도가 높아질수록 조금씩 낮아지는 경 향이었으나, 초폭이나 분지수에서는 차이가 없었다. 그러나 주방세제 200배 이하의 농도에서는 국화의 잎이 갈변되거나 꽃잎 끝이 백화되는 약해가 관찰되었다.