This study aimed to develop the in vitro method using domestic commercial diets to estimate nutrient digestibility in dogs. The existing in vitro method were tested and compared with literature data to develop new in vitro method. The development of in vitro method progressed as follows: modification of pepsin solution to an activated form and supplementation with 1% lipase. All the in vitro method progressed to 4 hours of stomach simulation and 2 hours of small intestine simulation. In vivo digestibility was measured using the same diets as beagle dogs. The supplementation of lipase methods showed significantly improved (p < 0.05) DM, OM, and EE than the existing and modified pepsin solution methods. The correlation between in vitro and in vivo data in DM, OM, and EE digestibility was high (r2 = 0.889, 0.907, and 0.721, respectively), and the correlation between in vitro and in vivo data in CP and GE digestibility was medium (r2 = 0.681 and 0.536, respectively). The current in vitro method is similar to in vivo digestibility and helps potentially predict digestibility for dogs. In conclusion, this developed in vitro method suggests that it can help estimate the nutrient digestibility of dogs' diets without in vivo experiments.

본 연구는 검거세미밤나방(Agrotis ipsilon) 성페로몬 트랩에 혼재하여 유살되는 은무늬밤나방아과 형태적 분류와 동정법 수립을 위해, 날개 무늬의 형태계측학 분석을 실시하였다. 은무늬밤나방아과 개체는 2023년 11월 부터 12월까지 제주도 애월읍 일대에서 채집되었으며, 콩 해충으로 알려진 콩은무늬밤나방(Ctenoplusia agnata) 을 비롯하여, 다양한 농작물을 가해하는 것으로 알려진 붉은금무늬밤나방(Chrysodeixis eriosoma)의 수컷 성충이 포획되었다. 앞날개의 형태 및 무늬를 가지고 현장에서 쉽게 동정할 수 있는 형태적 특징을 도출하기 위하여, 각 성충 개체의 앞날개를 잘라 현미경 카메라로 촬영하고, 앞날개의 내횡선, 아외연선, 반점 크기 등 15개의 형질 을 측정하였다. 또한 각 형질 간의 상관관계를 분석하였으며 빈도분포를 통하여 두 종간 분리되는 형질을 파악하 였다. 최종적으로 다변량 분석법을 적용하여 두 집단이 어떻게 군집을 이루는지 분석하고, 날개형태만으로 붉은 금무늬밤나방과 콩은무늬밤나방을 구분할 수 있는 방안을 제시하였다.

Tropilaelaps mercedesae Anderson and Morgan, 2007 (Acari: Laelapidae) is a serious ectoparasite of the brood of several honey bee species. Among the four recognized species of Tropilaelaps, Korean population was renamed as T. mercedesae from T. clareae on the basis of morphological evidences and genetic data. In this study, we report the complete mitochondrial genome (mitogenome) sequence of T. mercedesae. The 15,119-bp long mitogenome has an identical gene arrangement to that of Chinese sample reported previously. Comparison of two geographic samples showed COII, ND5, ND4, ND6, CytB, and ND1 to have higher number of variable sites than COI, which is often used for population-level study, suggesting these genes to have potential usefulness for population genetic study. The mitogenome sequence of T. mercedesae from Korea could be useful for species identification for geographic samples, trace of the origin of local populations, and illustration of evolutionary distinction among Tropilaelaps species either using part of or whole genome.

In May 2023, a free-living marine nematode species from the genus Parapinnanema was identified in the subtidal zone of Ulleungdo Island, the East Sea, Korea. Specimens were collected using the Smith-McIntyre Grab. These specimens exhibited close similarities to Parapinnanema imbricatum from the sublittoral of Moneron Island, particularly in terms of general characteristics, such as the detailed structure of the buccal cavity, the complex and ringed structure of the cuticle, the copulatory apparatus, spinneret, and the female genital system. However, the Korean specimens of Parapinnanema imbricatum also displayed distinctive features compared to the original description, including a relatively elongated body (3,317-4,339 μm vs. 3,100-4,200 μm) and a narrower body width (66-77 μm vs. 71-85 μm). Additionally, the diameter of the head was relatively shorter (24-29 μm vs. 28-36 μm). This paper offers a comprehensive morphological description, along with illustrations and DIC photomicrographs, of P. imbricatum from Korean waters.

산오이풀(Sanguisorba hakusanensis)은 한국의 자생식물 이며 정원소재로써 가치가 있지만, 생육 및 생리적 특성 및 정 원 적응 여부에 대하여 알려진 정보가 많지 않아 이용에 어려 움을 겪고 있다. 본 연구에서는 자생식물인 산오이풀의 관수 주기 및 NaCl 농도에 따른 생장, Fv/Fm, NPQ, 성분 변화, 무기성분 변화를 조사하여 내건 및 내염성 보유 여부, 생육 한 계 범위, 스트레스 환경에서 생육을 유지하기 위한 반응을 파 악하고자 했다. 실험 결과 NaCl 무처리구의 관수주기에 따른 성분 분석에서 엽록소 함량의 감소를 제외하고 유의한 차이가 나타나지 않았으나 이는 토양수분함량이 건조 스트레스를 유 발할 정도로 감소하지 않았기 때문으로 보인다. 염 처리에서 는 2주 이후 급격한 스트레스 반응이 나타났고 3주차부터 고 사하기 시작하여 6주차에 모든 개체가 최종 고사했다. 이러한 결과는 2주까지 염 스트레스에 의해 유발되는 2가지 스트레 스 중 초기에 나타나는 삼투 스트레스에는 저항하였으나 이후 나타나는 NPQ의 감소 등 이온 스트레스에 의해 유발된 광합 성 기구 붕괴로 인해 정상적인 생육을 유지할 수 없었기 때문 에 나타난 것으로 보인다. 그러나 무기이온 분석은 이온 스트 레스에 저항하기 위한 메커니즘의 존재 가능성을 시사하였다. 상대적으로 염 농도가 낮을 때에는 세포내 Ca2+ 및 K+ 수준이 높았는데, 이는 Ca2+ 수준이 높아짐에 따라 Na+를 세포 밖으 로 방출시키는 단백질, Na+를 K+와 함께 수송하는 단백질이 기능하여 Na+축적을 지연시키는 반응이 있었음을 시사한다. 그러나 NaCl을 고농도로 처리했을 때는 이러한 반응이 관찰 되지 않았다. 따라서 산오이풀은 염 스트레스에 의해 야기되 는 삼투 스트레스에 강한 저항성을 가지고 있고 이온 독성을 줄이기 위한 메커니즘으로 Na+ 세포내 축적을 지연시키는 것으로 보이지만, 심한 염 스트레스를 받았을 때 나타나는 급격 한 반응에서 이러한 메커니즘이 기능하지 못하고 이온독성에 매우 취약한 것으로 여겨진다. 본 연구를 통해 자생식물인 산 오이풀의 활용을 늘리는 데 기초적인 자료를 제공할 수 있을 것으로 생각된다.

In this study, we examined the antagonistic effects of sprout-borne lactic acid bacteria (LAB) on Salmonella enterica serovar Enteritidis. This antagonism is promoted as a means of controlling contamination during sprout production and provides additional LAB for consumers. We isolated a total of 24 LAB isolates in nine species and five genera from seven popular vegetable sprouts: alfalfa (Medicago sativa), clover (Trifolium pratense), broccoli (Brassica oleracea ssp. italica), vitamin (B. rapa ssp. narinosa), red radish (Raphanus sativus), red kohlrabi (B. oleracea var. gongylodes), and Kimchi cabbage (B. campestris var. pekinensis). Based on 16S rRNA gene sequences, the LAB species were identified as Enterococcus casseliflavus, E. faecium, E. gallinarum, E. mundtii, Lactococcus taiwanensis, Leuconostoc mesenteroides, Pediococcus pentosaceus, and Weissella cibaria, and W. confusa. A total of 16 LAB isolates in seven species including E. faecium, E. gallinarum, E. mundtii, L. taiwanensis, L. mesenteroides, P. pentosaceus, and W. cibaria showed antagonistic activity toward S. enterica. The growth inhibition of sprout LAB on S. enterica was confirmed by co-culture. Unexpectedly, sprout LAB failed to suppress the growth of S. enterica in alfalfa sprouts, whereas all LAB strains stimulate S. enterica growth even if it is not significant in some strains. The findings of this study indicate that S. enterica-antagonistic LAB are detrimental to food hygiene and will contribute to further LAB research and improved vegetable sprout production.

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.

KHNP is conducting research to decommission Wolsong Unit 1 Calandria. Establishment of preparation and dismantlement processes, conceptual design of equipment and temporary radiation protection facilities, and waste management are being established. In particular, the ALARA plan is to be established by performing exposure dose evaluation for workers. This study aims to deal with the methodology of evaluating exposure dose based on the calandria dismantling process. The preparation process consists of bringing in and installing tooling and devices, and removing interference facilities to secure work space. The main source term for the preparation process is the calandria structure itself and crud of feeders. In the case of the dismantlement process, a structure with a shape that changes according to the process was modeled as a radiation source. It is intended to estimate the exposure dose by selecting the number of workers, time, and location required for each process in the radiation field evaluated according to the preparation and dismantlement process. In addition, it is also conducting an evaluation of the impact on dust generated by cutting operations and the human impact of C-14, H-3, which are specialized nuclides for heavy water reactors. KHNP is conducting an exposure dose evaluation based on a process based on the preparation and dismantlement process for decommissioning Calandria through computation code analysis. If additional worker protection measures are deemed necessary through dose evaluation according to this methodology, the process is improved to prepare for the dismantling of worker safety priorities.

Radioactive waste (hereinafter referred to as mixed waste) containing hazardous substances (heavy metals, organic and inorganic waste liquids, asbestos, etc.) has been continuously generated from domestic nuclear power plants, nuclear facilities, and other industrial facilities, and heavy metals were released during the dismantlement of Kori Unit 1 and Wolseong Unit 1. Lead, cadmium, mercury, arsenic), asbestos, decontamination waste liquid (organic/inorganic waste liquid), etc. may be generated. Although hazardous waste related to the nuclear industry continues to be generated, only the regulation direction for hazardous substances is presented in the provisions related to hazardous substances in the delivery regulations for low and intermediate-level radioactive waste and the acceptance criteria for low and intermediate-level radioactive waste disposal facilities. In particular, because there is no clear definition of “hazardousness” and specific standards such as concentration and characteristics for classification of hazardous substances, as well as hazard removal procedures when the hazardousness of radioactive waste is confirmed, no hazardous substances have been delivered in Korea to date and many mixed wastes are stored at each generation facility or at the NPP. As a plan to improve delivery standards related to mixed waste is being prepared recently, it is believed that if the acceptance standards are revised accordingly, it will be possible to confirm the suitability for disposal of drums produced after the establishment of the acceptance standards in 2015. However, it is believed that securing disposal suitability for waste that was packed in 200L drums and compressed under super high pressure in the absence of specific technical standards and regulatory guidelines for the disposal of radioactive waste containing hazardous substances would still remain a difficult problem. In this report overseas acceptance standards related to hazardous waste were reviewed and a plan to secure the disposal suitability of 200 L drums compressed with of super high pressure was proposed.

Activated carbon (AC) is used for filtering organic and radioactive particles, in liquid and ventilation systems, respectively. Spent ACs (SACs) are stored till decaying to clearance level before disposal, but some SACs are found to contain C-14, a radioactive isotopes 5,730 years halflife, at a concentration greater than clearance level concentration, 1 Bq/g. However, without waste acceptance criteria (WAC) regarding SACs, SACs are not delivered for disposal at current situation. Therefore, this paper aims to perform a preliminary disposal safety examination to provide fundamental data to establish WAC regarding SACs SACs are inorganic ash composed mostly of carbon (~88%) with few other elements (S, H, O, etc.). Some of these SACs produced from NPPs are found to contain C-14 at concentration up to very-low level waste (VLLW) criteria, and few up to low-level waste (LLW) criteria. As SACs are in form of bead or pellets, dispersion may become a concern, thus requiring conditioning to be indispersible, and considering VLL soils can be disposed by packaging into soft-bags, VLL SACs can also be disposed in the same way, provided SACs are dried to meet free water requirement. But, further analysis is required to evaluate radioactive inventory before disposal. Disposability of SACs is examined based on domestic WAC’s requirement on physical and chemical characteristics. Firstly, particulate regulation would be satisfied, as commonly used ACs in filters are in size greater than 0.3 mm, which is greater than regulated particle size of 0.2 mm and below. Secondly, chelating content regulation would be satisfied, as SACs do not contain chelating chemicals. Also, cellulose, which is known to produce chelating agent (ISA), would be degraded and removed as ACs are produced by pyrolysis at 1,000°C, while thermal degradation of cellulose occurs around 350~600°C. Thirdly, ignitability regulation would be satisfied because as per 40 CFR 261.21, ignitable material is defined with ignition point below 60°C, but SACs has ignition point above 350°C. Lastly, gas generation regulation would be satisfied, as SACs being inorganic, they would be targeted for biological degradation, which is one of the main mechanism of gas generation. Therefore, SACs would be suitable to be disposed at domestic repositories, provided they are securely packaged. Further analysis would be required before disposal to determine detailed radioactive inventories and chemical contents, which also would be used to produce fundamental data to establish WAC.

Domestic waste acceptance criteria (WAC) require flowable or homogeneous wastes, such as spent resin, concentrated waste, and sludge, etc., to be solidified regardless of radiation level, to provide structural integrity to prevent collapse of repository, and prevent leaching. Therefore, verylow level (VLL) spent resin (SR) would also require to be solidified. However, such disposal would be too conservative, considering IAEA standards do not require robust containment and shielding of VLL wastes. To prevent unnecessary cost and exposure to workers, current WAC advisable to be amended, thus this paper aims to provide modified regulation based on reviewed engineering background of solidification requirement. According to NRC report, SR is classified as wet-solid waste, which is defined as a solid waste produced from liquid system, thus containing free-liquid within the waste. NRC requires liquid wastes to be solidified regardless of radiation level to prevent free liquid from being disposed, which could cause rapid release of radionuclides. Furthermore, considering class A waste does not require structural integrity, unlike class B and C wastes, dewatering would be an enough measure for solidification. This is supported by the cases of Palo Verde and Diablo Canyon nuclear power plants, whose wet-solid wastes, such as concentrated wastes and sludge, are disposed by packaging into steel boxes after dewatering or incineration. Therefore, dewatering VLL spent resin and packaging them into structural secure packaging could satisfy solidification goal. Another goal of solidification is to provide structural support, which was considered to prevent collapse of soil covers in landfills or trenches. However, providing structural support via solidification agent (ex. Cement) would be unnecessary in domestic 2nd phase repository. As the domestic 2nd phase repository is cementitious structure, which is backfilled with cement upon closure, the repository itself already has enough structural integrity to prevent collapse. Goldsim simulation was run to evaluate radiation impact by VLL SR, with and without solidification, by modelling solidified wastes with simple leaching, and unsolidified wastes with instant release. Both simulations showed negligible impact on radiation exposure, meaning that solidifying VLL SR to delay leaching would be irrational. Therefore, dewatering VLL SR and packaging it into a secure drum (ex. Steel drum) could achieve solidification goals described in NRC reports and provide enough safety to be disposed into domestic repositories. In future, the studied backgrounds in this paper should be considered to modify current WAC to achieve efficient waste management.

In Korea, most temporary storage facilities for spent nuclear fuel are nearing saturation. As an alternative to this, the 2nd basic plan for high-level radioactive waste management specified the operation plan of dry interim storage facility. Meanwhile, the NSSC No. 2021-19 stipulates that it is necessary to evaluate the possibility and potential effect of accident before operating interim storage facility. Therefore, this study analyzed the categories of accident scenarios that may occur in dry storage facility as part of prior research on this. We investigated the case of categorization of dry storage facility accident scenarios of IAEA, NRC, KAREI, and KINS. The IAEA presented accident scenarios that could occur in on-site dry storage facility operated with silo and cask method. NRC has classified accident scenarios in dry storage facility and estimated the probability of accidents for each. KAERI and KINS selected major accident scenarios and analyzed the processes for each, in preparation for the introduction of dry storage facility in Korea in the future. Overall, a total of 10 accident scenarios were considered, and the scenarios considered by each institution were different. Among 10 scenarios, cask drop and aircraft collision were included in the categorization of most institutions. The results of this study can be used as basic data for cataloging accidents subject to safety evaluation when introducing dry interim storage facility in Korea in the future.

아메리카동애등에 성충은 음식물 폐자원 등 유기물이 있는 곳에 알을 낳는 습성이 있다. 대부분의 농가는 음식 물폐자원을 가공한 단미사료(습식사료)를 유인배지로 활용하여 그 위에 플로랄폼(오아시스)를 놓고 알을 받는 다. 그러나 플로랄폼은 재사용이 불가하고 생분해되지 않는 환경폐기물로서 처리가 곤란하며 포름알데하이드, 카본 블랙 등의 발암물질을 함유한 것으로도 알려져 있다. 이에 본 연구는 먹이원 자체를 활용하여 폐기물이 발생하지 않는 친환경 산란받이를 개발하였으며 일회용으로 사용되는 플로랄폼을 대체하였다. 먹이원으로 활 용할 수 있는 습식사료와 건식사료를 주재료로 하여 제작하며, 습식사료(수분60~80%)와 건식사료(1~10%)를 1:0.5~1 비율로 혼합한 사료 혼합물과 보조첨가제와 물을 포함하여 제작한다. 친환경 산란받이는 기존 플로랄폼 대비 산란율이 34% 증가하였으며 구매비용 또한 75% 절감하였다.

벚나무류 수목은 생활권 수목(도시공원, 가로수 등)으로 전국에서 가장 많이 식재되고 있으며 전라 남도 또한 벚나무류 수목이 가로수 중 가장 많은 비율을 차지하고 있다. 복숭아유리나방은 농업환경 외에도 생활권 녹지공간에서도 벚나무류 수목을 가해하여 피해를 발생시키고 있는 것으로 보고되고 있으나, 생활권 수목과 산림에서의 관련 연구는 그 필요성에 비해 미흡한 상황이다. 본 연구는 전라남 도 내 생활권 수목을 기주로 하여 발생하는 복숭아유리나방의 발생소장을 조사하여 생활권 녹지공간 을 관리하는 기초자치단체들의 효용성 있는 방제 전략 수립에 기여하고자 한다. 복숭아유리나방의 발생 확인을 위해 육안 확인이 용이한 피해흔을 세 가지로 분류하였으며, 성페로몬 루어와 트랩으로 복숭아유리나방 성체를 유인･채집하였다. 그 결과, 4월 중순 첫 우화를 확인하였으며, 5월 중순과 8월 중순에 2번의 우화 최성기를 확인하여 이때의 유효적산온도를 조사하였다. 또한, 채집된 개체들 의 종 확인 및 유전적 다양성 확인을 위해 mitochondrial 내 cytochrome oxidase subunit I (COI) 유전자 염기 서열의 분석을 수행하였다.

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.

지난 2022년 제주도 애월읍 일대에서 콩 해충으로 알려진 콩은무늬밤나방(Ctenoplusia agnata) 성충이 검거세 미밤나방(Agrotis ipsilon)의 성페로몬 트랩에 대량으로 포획되었다. 검거세미밤나방 트랩은 목적 해충에 대한 포획 효율을 조사하기 위해 세 구성 성분, (Z)-7-dodecenyl acetate, (Z)-9-tetradecenyl acetate를 3:1 비율로 고정하고 (Z)-11-hexadecenyl acetate를 0, 1, 6, 10, 15로 각각 비율을 달리한 미끼를 사용하였다. 각 조성별 콩은무늬밤나방 성충 포획수를 비교한 결과, (Z)-11-hexadecenyl acetate가 첨가되지 않은 트랩에서 주당 평균 약 17.96마리로, 가장 많은 수의 개체가 포획된 것으로 확인되었다. 반면, (Z)-11-hexadecenyl acetate가 가장 많이 함유된 트랩에서 주당 평균 약 2.5마리로 가장 적은 개체가 포획된 것으로 파악되었다. 이에 (Z)-11-hexadecenyl acetate의 비율이 증가할 수록, 포획되는 콩은무늬밤나방의 개체 수가 감소되는 것을 확인할 수 있었다. 검거세미밤나방 미끼의 주성분인 Z)-7-dodecenyl acetate는 기존의 콩은무늬밤나방 유인 성분 중 하나이기도 하여 해당 성분의 구성비가 유인에 영향을 미쳤다는 것을 예측할 수 있다. 추후에 해당 트랩들과 시판 중인 콩은무늬밤나방 성페로몬 트랩을 설치하 여 포획 양상을 비교할 필요성이 요구된다.

Bombyx mandarina (Lepidoptera: Bombycidae), the presumed ancestor of B. mori, has long been a subject of study to illustrate the geographic relationships in connection with origin of B. mori. We report 97 mitochondrial genome (mitogenome) sequences of B. mandarina collected from Korea and Japan. Phylogenetic and population genetic analyses showed that all individuals of B. mandarina collected in Korean localities formed a strong group together with all individuals originated from northern China (mainly north of the Qinling-Huaihe line) and some of southern China. This group was placed as the sister group to B. mori strians suggesting that this group had been served as an immediate progenitor for B. mori.

Compared to operational wastes, nuclear power plant (NPP) decommissioning wastes are generated in larger quantities within a short time and include diverse types with a wider range of radiation characteristics. Currently used 200 L drums and IP-2 type transport containers are inefficient and restrictive in packaging and transporting decommissioning wastes. Therefore, new packaging and transport containers with greater size, loading weight, and shielding performance have been developed. When transporting radioactive materials, radiological safety should be assessed by reflecting parameters such as the type and quantity of the package, transport route, and transport environment. Thus far, safety evaluations of radioactive waste transport have mainly targeted operational wastes, that have less radioactivity and a smaller amount per transport than decommissioning wastes. Therefore, in this study, the possible radiation effects during the transport from NPP to disposal facilities were evaluated to reflect the characteristics of the newly developed containers and decommissioning wastes. According to the evaluation results, the exposure dose to transport workers, handling workers, and the public was lower than the domestic regulatory limit. In addition, all exposure dose results were confirmed, through sensitivity analysis, to satisfy the evaluation criteria even under circumstances when radioactive materials were released 100% from the container.

Mass production of high-quality carbon nanotubes (CNTs) remains a challenge, requiring the development of new wetimpregnated catalyst suitable for the catalytic chemical vapor deposition (CCVD) of CNTs in a fluidized bed reactor. For the successful development of a new catalyst, a highly robust system to synthesize CNTs must be established. Here, we systematically investigated the robustness of CNT synthesis by CCVD using a wet-impregnated catalyst. We statistically tested four factors that could potentially affect the robustness of CNT synthesis system, focusing on carbon yield and IG/ID. First, we tested the effect of vacuum baking before CNT growth. F test and CV equality test concluded that vacuum baking recipe did not significantly reduce the variability of the CNT synthesis. Second, we tested the batch-to-batch variation of catalysts. The results of t test and one-way analysis of variance indicate that there is significant difference in carbon yield and IG/ID among catalysts from different batches. Third, we confirmed that there is spatial non-uniformity of wet-impregnated catalysts within a batch when they are produced in large scale. Finally, we developed a multi-step heating recipe to mitigate the temperature overshooting during the CNT synthesis. The multi-step recipe increased the mean of carbon yield, but did not influence the variability of CNT synthesis. We believe that our research can contribute to the establishment of a robust CNT synthesis system and development of new wet-impregnated catalysts.

KHNP is carrying out international technical cooperation and joint research projects to decommission Wolsong unit 1 reactor. Construction data of the reactor structures, experience data on the pressure tube replacement projects, and the operation history were reviewed, and the amount of dismantled waste was calculated and waste was classified through activation analysis. By reviewing COG (CANDU owners Group) technical cooperation and experience in refurbishment projects, KHNP’s unique Wolsong unit 1 reactor decommissioning process was established, and basic design of a number of decommissioning equipment was carried out. Based on this, a study is being conducted to estimate the worker dose of dismantling workers. In order to evaluate the dose of external exposure of dismantling workers, detailed preparation and dismantling processes and radiation field evaluation of activated structures are required. The preparation process can be divided into dismantlement of existing facilities that interfere with the reactor dismantling work and construction of various facilities for the dismantlement process. Through process details, the work time, manpower, and location required for each process will be calculated. Radiation field evaluation takes into account changes in the shape of structures by process and calculates millions of areas by process, so integrated scripts are developed and utilized to integrate input text data. If the radiation field evaluation confirms that the radiation risk of workers is high, mutual feedback will be exchanged so that the process can be improved, such as the installation of temporary shields. The results of this study will be used as basic data for the final decommissioning plan for Wolsong unit 1. By reasonably estimating the dose of workers through computer analysis, safety will be the top priority when decommissioning.