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.

Reliable evaluation of radioactivity inventory for the nuclear power plant components and residual materials is very important for decontamination and decommissioning. This can make it possible to define optimum dismantling approaches, to determine radioactive waste management strategies, and to estimate the project costs reasonably. To calculate radioactivity of the nuclear power plant structure, various information such as interest nuclide, cross-section, decay constant, irradiation time, neutron flux, and so on is required. Especially irradiation time and neutron flux level are very changeable due to cycle specific fuel loading pattern, the plant overhaul, cycle length. However most of the radioactivity calculations have generally been performed assuming one representative or average neutron flux during the lifetime of the nuclear power plant. This assumption may include excessive conservatism because the radioactivity level has the characteristics of saturation and decay. Therefore, considering these variables as realistically as possible could prevent overestimation. In order to perform realistic radioactivity calculation, we developed monthly relative power contribution factor applying plant-specific operation history and cycle-specific neutron flux. The factors were applied to the radioactivity calculation. The calculation results ware compared with measured values of the neutron monitors that were actually installed and withdrawn from the nuclear power plant. As a result of the comparisons, there are good agreements between the calculated values and measured values. These accurate calculation results of radioactivity could contribute to the establishment of radioactive waste dismantling strategies, the classification of radioactive waste, and the deposit of disposal costs for safe and reasonable decommissioning of the nuclear power plant.

With the aging of nuclear power plants (NPPs) in 37 countries around the world, 207 out of 437 NPPs have been permanently shutdown as of August 2022 according to the IAEA. In Korea, the decommissioning of NPPs is emerging as a challenge due to the permanent shutdown of Kori Unit 1 and Wolsong Unit 1. However, there are no cases of decommissioning activities for Heavy Water Reactor (HWR) such as Wolsong Unit 1 although most of the decommissioning technologies for Light Water Reactor (LWR) such as Kori Unit 1 have been developed and there are cases of overseas decommissioning activities. This study shows the development of a decommissioning waste amount/cost/process linkage program for decommissioning Pressurized Heavy Water Reactor (PHWR), i.e. CANDU NPPs. The proposed program is an integrated management program that can derive optimal processes from an economic and safety perspective when decommissioning PHWR based on 3D modeling of the structures and digital mock-up system that links the characteristic data of PHWR, equipment and construction methods. This program can be used to simulate the nuclear decommissioning activities in a virtual space in three dimensions, and to evaluate the decommissioning operation characteristics, waste amount, cost, and exposure dose to worker. In order to verify the results, our methods for calculating optimal decommissioning quantity, which are closely related to radiological impact on workers and cost reduction during decommissioning, were compared with the methods of the foreign specialized institution (NAGRA). The optimal decommissioning quantity can be calculated by classifying the radioactivity level through MCNP modeling of waste, investigating domestic disposal containers, and selecting cutting sizes, so that costs can be reduced according to the final disposal waste reduction. As the target waste to be decommissioning for comparative study with NAGRA, the calandria in PHWR was modeled using MCNP. For packaging waste container, NAGRA selected three (P2A, P3, MOSAIK), and we selected two (P2A, P3) and compared them. It is intended to develop an integrated management program to derive the optimal process for decommissioning PHWR by linking the optimal decommissioning quantity calculation methodology with the detailed studies on exposure dose to worker, decommissioning order, difficulty of work, and cost evaluation. As a result, it is considered that it can be used not only for PHWR but also for other types of NPPs decommissioning in the future to derive optimal results such as worker safety and cost reduction.

According to Article 4 and 5 of the Nuclear Safety and Security Commission (NSSC) Notice No. 2020-6, radioactive waste packages should be classified by radioactive levels, and finally permanently shipped to underground or surface disposal facilities. The level of the radioactive waste package is determined based on the concentrations of the radionuclides suggested in Article 8 of NSSC Notice No. 2021-26. Since most of the radionuclides in radioactive wastes are beta nuclides, chemical separation and quantification of the target nuclides are essential. Conventional methods to classify chemically non-volatile radionuclides such as Tc-99, Sr-90, Nb- 94, Fe-55 take a lot of time (about 5 days) and have low efficiency. An automated non-volatile nuclide analysis system based on the continuous chemical separation method of radionuclides has been developed to compensate for this disadvantages of the conventional method in this study. The features of the automated non-volatile nuclide separation system are as follows. First, the amount of secondary waste generated during the chemical separation process is very small. That is, by adopting an open-bed resin column method instead of a closed-bed resin column method, additional fittings and connector are unnecessary during the chemical separation. In addition, because the peristaltic pump is supplied for the sample and solution respectively, it is great effective to prevent cross-contamination between radioactive samples and the acid stock solution for analysis. Second, the factors that may affect results, such as solution amount, operating time and flow rate, are almost constant. By mechanically controlling the flow rate precisely, the operating time and additional factors required during the separation process can be adjusted and predicted in advance, and the uncertainty of the chemical separation process can be significantly reduced. Finally, it is highly usable not only in the continuous separation process but also in the individual separation process. It can be applied to the individual separation process because the user can set the individual sequence using the program. As a result of the performance evaluation of the automation system, recovery rates of about 80–90% and reproducibility within 5% were secured for all of the radionuclides. Furthermore, it was confirmed that the actual work time was reduced by more than 50% compared to the previous manual method. (It was confirmed that the operation time required during the separation process was reduced from 6 days to 3 days.) Based on these results, the automation system is expected to improve the safety of workers in radiation exposure, reduce human error, and improve data reliability.

Background: Chronic ankle instability is a common injury that decreases balance and negatively affects functional movements, such as jumping and landing. Objectives: To analyze the effect of taping types and jump heights on balance with eyes open and closed during jump landings in chronic ankle instability. Design: Within-subject design. Methods: The study involved 22 patients with chronic ankle instability. They performed both double-leg and single-leg drop jump landings using three conditions (elastic taping, non-elastic taping, and barefoot) on three different jump platforms (30, 38, and 46 cm). Balance was measured using the Romberg's test with eyes open and closed. Results: Interaction effect was not statistically significant. Balance with eyes open and closed was significantly improved in both the elastic taping and non-elastic taping conditions compared to the barefoot condition. There was no significant difference according to the jump height. Conclusion: Individuals with chronic ankle instability demonstrated increased balance ability with eyes open and closed when jump landing. Elastic taping and non-elastic taping on the ankle joint can positively affect balance during landing in individuals with chronic ankle instability.

최근에는 4차 산업혁명 시대로서 인공지능, IOT(Internet of Things) 등 모든 산업의 핵심은 소프트웨어로 이러한 시대의 변화에 맞게 소프트웨어 교육 즉 코딩 교육에 대한 관심이 고조되며 화두가 되고 있다. 컴퓨팅 사고력 검사에서는 평가, 분해, 알고리즘에 유의미한 상승이 있는 것으로 나타났고, 창의력 검사에서는 독창성, 성급한 종결에 대한 저항에 통계적으로 유의미한 상승이 있는 것으로 나타났다. 이러한 결과는 본 연구의 미술 코딩 교육 프로그램에서 강조하고 있는 컴퓨팅 사고력과 창의력을 향상시켜주며 이를 통해 프로세싱을 활용한 미술 코딩 교육 프로그램만으로도 효과가 있다는 것을 알 수 있다. 아직 교육 현장에서는 변화의 물결에 대응할 만큼 소프트웨어 교육을 통한 미래 인재 양성 교육에 대한 인식과 관심, 준비가 충분하지 못한 것이 현실이다. 본 연구는 이러한 교육의 목적 달성에 기여하고자 컴퓨팅 사고력과 창의력 향상을 위한 미술 코딩 교육 프로그램에 대한 실험 연구로 좀 더 다양한 주제로 게임 코딩 교육 프로그램 개발에도 적용될 것이다.

Oyster mushroom is one of mushrooms that are cultivated and consumed a lot in Korea. P. ostreatus 'Suhan(ASI2504)' is a popluar cultivar because of high quality. But it is difficult for farmers to cultivate, so an alternative cultivar of ‘Suhan’ is demanded continuously. To develop a new variety, parental strains were selected using cultivation characteristics of Pleurotus ostreatus collected home and abroad. P. ostreatus 'Gosol' was developed by the method of Di-Mon crossing between dikaryotic strain P. ostreatus 'Mongdol(ASI0633)' and monokaryotic strain derived from P. ostreatus ‘Yasan(ASI0635)' in 2014. Analysis of the genetic characteristics of the new cultivar 'Gosol' showed a different DNA profile as that of the control strain, 'Suhan’ but a similar DNA profile as those of the parental strains, ‘Yasan’ and　'Mongdol’, when RAPD(Random Amplified Polymorphic DNA) primer URP 3 was used. The optimum temperature for mycelial growth was 25°C for ‘Gosol’ and ‘Suhan’. 'Gosol' was appropriate for middle high temperature to grow, especially 13~18°C. Fruiting body production per bottle was about 124.2g. When compared to the control strain 'Suhan’, the stipe was longer and the individual weight was heavier. But the stipe and the pileus were a little thinner than those of the control strain. ‘Gosol’ was more resistant at high CO2 concentration than the control strain. This new cultivar ‘Gosol’ of Pleurotus ostreatus was characterized dark bluish gray cultivar of oyster mushroom in the color of pileus and higer yield compared to those of other cultivar ‘Suhan’. Therefore, it is suggested that this new cultivar ‘Gosol’ be substitute for ‘Suhan’ in oyster mushroom’s farms.

Flexible transparent conducting films (TCFs) were fabricated by dip-coating single-wall carbon nanotubes (SWCNTs) onto a flexible polyethylene terephthalate (PET) film. The amount of coated SWCNTs was controlled simply by dipping number. Because the performance of SWCNT-based TCFs is influenced by both electrical conductance and optical transmittance, we evaluated the film performance by introducing a film property factor using both the number of interconnected SWCNT bundles at intersection points, and the coverage of SWCNTs on the PET substrate, in field emission scanning electron microscopic images. The microscopic film property factor was in an excellent agreement with the macroscopic one determined from electrical conductance and optical transmittance measurements, especially for a small number of dippings. Therefore, the most crucial factor governing the performance of the SWCNT-based TCFs is a SWCNT-network structure with a large number of intersection points for a minimum amount of deposited SWCNTs.

At present, multimedia systems have recently gained more and more popularity due to the widely use of digitally formatted audio, video, and printed information in network environment. In such respect, there is a serious threat that authors, publishers and providers of multimedia data are reluctant to allow the distribution of their data in a network due to the ease of widespread redistribution in their original form likely to enhance copyright violation. One way to address the problem is to hide invisible data in the content that has to be protected. This technology is called watermarking and which is widely used for traditional multimedia data types such as images, video and audio. First related publications date back to 1979 and it gained a large international interest in 1990. In this paper, we introduce how and what the digital watermarking are undergone to three dimensional models.

Laparoscopic appendectomy using three trocars has been widely performed. Recently, a single incision laparoscopic surgical procedure has become popular because it is less invasive. We report on our early experience in performance of single incision laparoscopic appendectomy (SIL-A). Data on the operating time, the duration to make the pneumoperitoneum, body mass index (BMI), rate of conversion to another operation, complication, hospital stay, dosage of analgesics, and pain score were collected prospectively at two centers. Twenty seven patients underwent SIL-A. The mean BMI was 23.3±3.1 kg/m2 (17.6-30.5). The mean time required to make a pneumoperitoneum was 9.9±5.0 minutes (5.0-28.0). The mean operating time was 37.6±26.7 minutes (10.0-100.0). The rate of intra-operative complication was 3.7% (1/27), and the rate of post-operative complication was 22.2% (6/27). The mean hospital stay was 4.1±1.2 days (2-6). The immediately postoperative pain score was 5.4±1.5 (3-8), however, the pain score at discharge was 0.4±0.7 (0-2). The mean dosage of analgesics was 1.5±1.3(0-4), however, none of the patients took analgesics after postoperative three days. SIL-A is feasible but requires improved instrumentation and experience.