Silage inoculants, crucial in modern silage production, comprise beneficial microorganisms, primarily lactic acid bacteria (LAB), strategically applied to forage material during ensiling. This study aimed to compare the effectiveness of various inoculants produced by different companies. Five treatments were evaluated, including a control group: T1 (Lactobacillus plantarum), T2 (Lactobacillus plantarum + Pediococcus pentosaceus), T3 (Lactobacillus plantarum + Pediococcus pentosaceus + Lactobacillus buchneri), T4 (Lactobacillus plantarum + Lactobacillus acidophilus + Lactobacillus bulgaricus), and T5 (Lactobacillus plantarum + Pediococcus pentosaceus + Enterococcus faecium). Italian ryegrass was harvested at the heading stage and treated with these silage inoculants. Samples were collected over a 60-day ensiling period. Co-inoculation with L. plantarum and P. pentosaceus (T2) resulted in significantly higher CP compared to the control group co-inoculation exhibited with resulted in Lactobacillus plantarum and Pediococcus pentosaceus in the T2 treatment exhibited higher CP content of 106.35 g/kg dry matter (DM). The T3 treatment, which included heterofermentative bacterial strains such as Lactobacillus buchneri, exhibited an increase in acetic acid concentration (11.15 g/kg DM). In the T4 treatment group, which utilized a mixed culture of Lactobacillus acidophilus and Lactobacillus bulgaricus, the NH3-N/TN content was observed to be the lowest (20.52 g/kg DM). The T5 containing Enterococcus faecium had the highest RFV (123) after 60 days. Expanding upon these findings, the study underscores not only the beneficial effects of particular inoculant treatments on silage quality but also underscores the potential of customized inoculation strategies in maximizing nutrient retention and overall silage preservation.

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.

The 2007 Recommendation of the International Commission on Radiological Protection recommended the application of dose constraints to optimize radiation protection to resolve the inequity of exposure among radiation workers. The average annual occupational doses in Korean nuclear power plants (NPPs) are 0.3-0.8 mSv. These doses are much lower than the annual effective dose limit of 50 mSv for radiation workers stipulated by the Nuclear Safety Act. In addition, most NPP workers received less than 0.1 mSv per year. These doses are lower than the average annual occupational doses of 0.3- 0.8 mSv. Korean regulatory body conducted the study to legislate the dose constraints in the Korean regulatory system and determine dose constraints (draft) for radiation workers. The legislation of dose constraints would not greatly affect the radiation protection programs in Korean NPPs because most workers received very low doses. However, some workers received relatively higher doses than others. This study analyzed the occupational exposure conditions, such as exposure type and situation, in Korean NPPs. This study investigated the internal and external radiation doses and the radiation doses depending on the NPP operating conditions, including normal operation, planned maintenance, and intermediate maintenance, for the last ten years (2012-2021). As a result, most NPP workers received external exposure rather than internal exposure. Furthermore, most radiation exposures occurred during the planned maintenance period. The results of this study can be used for optimizing occupational doses in Korean NPPs.

As of 2023, there are a total of 24 nuclear power plants (NPPs) in operation in Korea, with 21 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Korean NPPs discharge radioactive effluents into the environment every year. Radioactive effluents from NPPs contain various radionuclides and materials, including 3H, 14C, Noble gas, particulates, and iodine Among the radioactive effluents discharged from Korean NPPs, 14C is a pure beta emitter with a half-life of 5,730 years. The human body can inhale and ingest 14C to cause internal exposure. In addition, the amount of 14C present in the environment is decreasing, but the amount of 14C discharged from NPPs is increasing. 14C discharged to the environment can be inhaled and ingested by the public around NPPs through various pathways. For this reason, it is very important to monitor and manage 14C because it affects the dose of the public around NPPs. Therefore, this study compared and analyzed the average emissions of 14C discharged from PWRs and PHWRs during the recent 10 years (2012-2021). An average of the public dose due to 14C released from NPPs depending on the reactor types from 2012 to 2021 was also compared. It is inevitable to discharge radioactive effluents while operating NPPs. Korea Hydro & Nuclear Power (KHNP) manages and monitors radioactive effluents released into the environment. According to a survey and analysis of 14C discharged from PWRs and PHWRs and the average dose of the public over the recent 10-year (2012-2021) around Korean NPPs, 14C released from PWR accounted for 3.1% of the total discharge but accounted for more than 93.67% of the total public dose. In addition, 14C discharged from PHWRs accounted for 1.12% of the total discharge, but its resulting dose to the public accounted for more than 83.87% of the total public dose. As a result of analyzing the public dose due to 14C from 2012 to 2021, it was gradually increasing every year. Based on these results, monitoring and managing 14C discharge and its resulting doses to the public are important in the future.

After the Fukushima nuclear accident in Japan in March 2011, many Koreans were concerned that products exposed to radioactive materials released from the nuclear power plant would be imported into Korea. Systematic radiation monitoring was required for food and daily necessities imported from the nuclear accident area. The need for a legal system to support systematic radiation monitoring was also demanded. The Act on Protective Action Guidelines against Radiation in the Natural Environment was enacted to resolve concerns regarding environmental radiation in Korea in July 2011. According to this law, radiation monitoring equipment has been installed and operated at major airports and ports nationwide. This paper aims to review the radiation monitoring system of the Korean government comprehensively. The legal system and the legal basis for radiation monitoring of imported cargo conducted by each department were investigated by analyzing the laws and regulations of radiation monitoring for the relevant cargo items. In addition, the current status of radiation monitoring by the government departments was examined to determine how radiation monitoring for imported cargo is performed within the legal system. The investigation of the current radiation monitoring system for imported cargo in Korea confirmed that radiation monitoring is conducted by classifying cargo items under the jurisdiction of each government department for all imported cargo. However, the reduction in efficiency of radiation monitoring of imported cargoes, unclear legal grounds for radiation monitoring of imported cargo by some departments, the occurrence of overlapping inspections by departments, and the difficult process of issuing the radiation test certificate required for customs clearance by the Korea Customs Service were also identified. As a result of the analysis, it was found that the current radiation monitoring system for imported cargo in Korea ought to be improved, taking into account efficiency, overlapping inspection, legal background, and the difficult process of issuing the certificates.

Metal waste generated during the dismantling of a nuclear power plant can be contaminated with radionuclides. In general, the internal structure is very complex. Thus, metal waste requires various cutting processes. When metal waste is cut, aerosols are generated. Aerosols are generally various particles of very small size suspended in the working area and remain for a considerable period. This may cause internal exposure of workers due to inhalation of radioactive aerosols generated when cutting radioactive metal waste. This study investigated various cutting processes and the size distribution of aerosols generated during the cutting process. The cutting process is normally classified into thermal cutting, mechanical cutting, and laser cutting. Thermal cutting includes plasma, flame, and oxygen cutting. Mechanical cutting includes mechanical saws, cutters, nibblers, and abrasive water jets. Stainless steel, carbon steel, aluminum, and copper are commonly used as cutting materials in nuclear power plants. The size of the aerosol generated from cutting showed a very diverse distribution depending on the cutting methods and cutting materials. In general, aerosol size is distributed within 0.1-1 μm. This size distribution is different from the 5 μm aerosol size suggested by the ICRP Publication 66 Lung model. These results show that it is necessary to conduct further studies on the size of aerosols generated when decommissioning nuclear power plants.

Currently, there are 25 nuclear power plants (NPPs) in operation in Korea, including 22 pressurized water reactors (PWRs) and three pressurized heavy water reactors (PHWRs). Two NPPs, including Kori Unit 1 and Wolsong Unit 1, are permanently shut down and awaiting decommissioning. If Kori Unit 2, which is expected to be permanently shut down soon, is included, the number of decommissioning NPPs will be increased to three. Spent fuels (SFs) are continuously generated during the NPP operation, which are stored in an SF storage pool in NPPs to cool down the decay heat emitted from SFs. For safe NPP operation, SFs must be regarded as waste, and a disposal site must be selected to isolate SFs. However, an appropriate site has yet to be selected in Korea. SFs contain long-lived nuclides with a high specific activity. For disposal, it is important to characterize the nuclides in the fuels and delay the migration of the nuclides to the environment when SFs are placed in a future disposal facility. If the disposal container is broken, the nuclides in the fuels escape from the filling material, such as bentonite. These escaped nuclides are dissolved in groundwater and migrate to the surface of the earth. Thus, it is possible to assess the radiological impact, such as the exposure dose during and after the disposal, if the types and characteristics of nuclides in SFs are known. This study investigated the nuclides in SFs and identified exposure scenarios that may occur in the disposal process of SFs and migration characteristics when the nuclides leak into groundwater to propose a dose assessment methodology for workers and the public.

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.

The carbon anode material for lithium-ion battery was prepared by pyrolysis fuel oil and waste polyethylene terephthalate (PET) additive. The pitch was synthesized as a medium material for carbon anode by heat treatment. The waste PET additive improved the softening point and thermal stability of the pitch. La and Lc of the anode material (heat-treated pitch) increased at higher treatment temperature but decreased by waste PET additive. The electric capacity was evaluated based on effects of defective cavity and developed graphite interlayer, respectively. When the La and Lc of the anode material decreased, the electric capacity by cavity increased based on defective graphite structure. Therefore, the addition of waste PET causes the improved capacity by the cavity. The anode material which has a high efficiency (over 95%) and C-rate (95%, 2 C/0.1 C) was obtained by controlling the process of heat treatment and PET addition. The mechanism of lithium-ion insertion was discussed based on effects of defective cavity and developed graphite interlayer.

Dermanyssus gallinae is parasitic to chicken, and they cause many damages such as disturbing sleep reducing for body weight and egg production by blood-sucking. To develop acaricide against D. gallinae, The acaricidal activity of 40 species plant extract were examined. Cnidium officinale extracted by Me-OH showed 82.0% acaricidal activity after treated 48 hrs at 4,000 ppm. The hexane fraction showed 92.4% mortality against D. gallinae at 48 hrs at 2,000 ppm. Purification of the biologically active constituents from the hexane extraction with acaricidal activity was done using silica gel open column chromatography and HPLC. H1122 fraction gave 80.9% mortality to D. gallinae at 400 ppm after treated 48 hrs. H1122 fraction was analyzed by GC-MS and NMR.

Rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5㎎/ℓ L-cysteine, 1mM sodium thiosulfate, 1mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5㎎/ℓ silver nitrate). Co-cultivation temperature (23. 5℃ for 1 day, 26.5℃ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.

Rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5㎎/ℓ L-cysteine, 1mM sodium thiosulfate, 1mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5㎎/ℓ silver nitrate). Co-cultivation temperature (23. 5℃ for 1 day, 26.5℃ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.