A study on the denitrification of reverse osmosis(RO) concentrated wastewater from sewage reuse treatment plant in P city was conducted using waste desulfurization agent obtained from desulfurization process. Sulfur-based autotrophic denitrifying carrier comprises the predetermined amount of waste iron sulfide (FeS, Fe2S3), mine drainage sludge and elemental sulfur showing mesoporisity with 9.9 nm (99 Å) of average pore size. Sulfur denitrifying bacteria and sulfur reducing bacteria were implanted into the pores of sulfur denitrifying carrier. Nitrate was not affected by empty bed contact time (EBCT). It is probably due to larger reducing capacity of the carrier than the concentration of nitrate in RO concentrated wastewater. Total nitrogen (T-N) removal efficiency exhibited about 90% after 4 days. Sulfate ion was surprisingly decreased with sulfur autotropic process due to the reduction of sulfate ion to HS- and S2- by sulfur reducing bacteria. Sulfide and hydrogen sulfide ions were then taken by Fe(OH)3, main component of mine drainage sludge, releasing OH-. Alkalinity was therefore maintained between 7.5 and 8.5 in pH by the released OH-. Also, it had the effect of suppressing the production of H2S, which causes bad odor.
For safe and successful decommissioning, it is one of the most important procedures that establishing the goal and complying with regulations of which final status of decommissioned site and building. The dose criteria for cyclotron facilities should be established and applied to reuse the site and building, since building and component of a cyclotron facility have been activated by incident secondary neutrons from radioactive isotope processes (e.g. 18O(p,n)18F, etc.). Furthermore, appropriate approaches should be applied to demonstrate compliance with the dose criteria for reliability of reuse. It is of noted that U.S. NRC (Nuclear Regulatory Commission) has confirmed that the residual radioactivity which distinguishable from background radiation results in a TEDE (Total Effective Dose Equivalent) does not exceed 25 mrem (0.25 mSv) per year as radiological criteria for unrestricted use of not only nuclear power plants but also cyclotron facilities referred to 10 CFR Part 20.1402. In addition, U.S. NRC noted the two approaches (i.e. dose assessment methods and, DCGL and final status surveys) which can be applied for demonstrating compliance with the dose criteria of 10 CFR Part 20 and recommended DCGL and FSS approach based on advantages and disadvantages of the two approaches. In order to using DCGL and FSS approach, U.S. NRC suggested screening approach; using DandD Version 2 which assesses TEDE under ICRP 28 and site-specific approach; using all models or computational codes which approved by NRC staff. There are several foreign cases that release of cyclotron facilities after decommissioning (i.e. U.S. and Japan). U.S., for examples, there are two DCGL approach cases and one dose modeling case based on 25 mrem per year same as reactor facilities. The dose modeling case, however, which may not be really used in Korea because of its low applicability. On the other hand, Japan case did not establish any radiological criteria for site and building reuse such as DCGL and just confirm “no more contamination” which is all residual radioactivity is lower than MDC based on real survey. Japan case also may not be used in Korea since criteria of “no more contamination” is not clear and hard to apply for all sites. Considering regulations and criteria for site release and reuse in Korea, this study aims to suggest radiological criteria and the demonstration approach of compliance for decommissioning of cyclotron facilities based on Nuclear Safety Acts and NSSC notices.
This study investigated the relationship between service quality factors, customer satisfaction, and reuse intention based on the degree of attachment to companion animals felt by caregivers when using dog grooming services. An online and offline survey with caregivers experienced in dog grooming services were conducted, and 304 responses were analyzed using SPSS 26.0 Statistics Program. The analysis revealed the following. First, sub-factors of dog grooming service quality: empathy, assurance, tangibles, and reliability, significantly affect customer satisfaction. Second, customers satisfaction with dog grooming services significantly affects their reuse intention. Third, only reliability demonstrates a moderating effect on attachment to companion dogs in influencing the relationship between customer satisfaction and service quality. These findings that service quality management is necessary to improve the business performance of dog-grooming services. Particularly, this study is meaningful in presenting the direction of service marketing centered on trust, as more guardians consider companion dogs as family.
가상현실과 현실 세계를 융합한 공간으로서 가상의 세계 안에서 다양 한 상호작용과 경험을 제공하는 메타버스 서비스는 사용자들이 자아일치 성을 공유하고 강화하는 공간을 형성해줄 수 있다. 본 연구에서는 메타 버스 서비스 특성이 사용자의 재이용의도에 미치는 영향과, 이 관계를 매개하는 자아일치성의 효과를 검증하였다. 메타버스 서비스를 이용해 본 경험이 있는 성인 남녀를 대상으로 수집한 245개 설문자료를 분석한 결과에 따르면 메타버스 서비스 특성 중 실재감과 매개변수인 자아일치 성은 고객의 메타버스 재이용의도에 긍정적인 영향을 미치는 것으로 나 타났다. 또한 매개효과분석 결과에 따르면 자아일치성은 메타버스 서비 스 특성 중 실재감과 재이용의도 간의 관계를 부분매개하고, 유용성과 재이용의도 간의 관계, 상호작용성과 재이용의도 간의 관계를 완전매개 하는 것으로 나타났다. 연구 결과는 변화된 환경과 소비자 특성으로 인 해 전통적 브랜드 마케팅 방식의 한계에 직면하고 있는 기업들에게 메타 버스를 활용한 마케팅 전략 도출에 도움이 되는 유용한 정보를 제공하고 있다.
To compete with the growth of fashion shopping platforms in the online fashion market, general shopping platforms have begun to expand their product categories to include fashion items. This research examines the characteristics that influence consumers’ trust in each of these platforms and their intention to reuse them. Applying the concept of platforms, this study also distinguishes between general shopping platforms and fashion shopping platforms and compares their characteristics. This study surveyed 788 consumers in their 20s and 30s with experience in using general shopping platforms or fashion shopping platforms (389 and 399 respondents, respectively). SPSS was used to conduct frequency analysis, factor analysis, and cross-tabulations, and AMOS was used to conduct confirmatory factor analyses and structural equation analyses. The results were as follows: platform reputation, shopping convenience, and interactivity all influenced consumer trust. For fashion shopping platforms, the product quality factor significantly improved consumer trust. However, for general shopping platforms, the product quality factor only influenced reuse intentions to reuse and did not contribute to improving trust. Platform reputation and information offering have influenced reuse intentions for both shopping platforms. Regardless of the type of shopping platform, platform reputation has influenced reuse intentions and consumer trust, and platform esthetics didn’t have affect consumer trust and consumers’ reuse intentions. Consumer trust influenced the intention to reuse on both platforms.
The effects of an individual effective dose from radioactive contamination that will remain during site reuse after the decommissioning of nuclear facilities is generally assessed using the RESRAD code. The calculated results should meet the site reuse criteria presented by regulators, 0.25 mSv/yr in the United States and 0.1 mSv/yr in Korea. After completion of decommissioning, the dose is not subject to measurement, resulting in Derived Concentration Guideline Level (DCGL) remaining at the site that is practically consistent with the dose criteria. In order to assess dose using the RESRAD code, various requirements will need to be considered and determined, where the selection of input parameters is one of the important factors in the dose assessment. In addition, appropriate selection of site-specific parameters is important to reflect the site characteristics of each decommissioned Nuclear Power Plant (NPP). Therefore, this study intends to analyze the impact of site-specific parameters by referring to the cases of overseas decommissioned NPPs. In order to evaluate doses using RESRAD code, a site reuse scenario must first be selected. In general, in the case of unrestricted reuse, the resident farmer scenario can be applied, so the resident farmer scenario was also selected in this study. In addition, once a resident farmer scenario is selected, input parameters are selected according to the scenario, and the input parameter inputs a single value or distribution according to the deterministic or probabilistic evaluation method. Therefore, since this study is to evaluate the effect on site-specific parameters, a single value was applied as a deterministic evaluation method. For the 10 site-specific parameters considered in overseas cases, the difference was set twice using the F9 function key in the RESRAD code and the results were analyzed. In this study, we used prior research data targeting domestic nuclear facility for sensitivity analysis. Related parameters include the category of contamination layer, soil, water transport, ingestion, and occupancy. The parameters that appeared as the greatest influence among the 10 parameters were different in radionuclide on the contaminated zone. We showed the changes according to the difference in input parameters was presented using the graph provided by the RESRAD code. As a result, in the evaluation for Co-60 in this study, no significant change was observed. However, in case of H-3, several parameters values were changed, indicating that the effect on dose will be different depending on the site characteristics of the nuclear facilities.
본 연구에서는 파프리카(Capsicum annuum L.) ‘Scirocco’ 품종 수경재배 시 배액 재사용 여부에 따른 순환식 재배와 비 순환식 재배 및 배지 종류가 배액의 양분 이온 변화 양상과 생 육에 미치는 영향을 조사하였다. 파프리카의 파종은 2021년 8 월 19일에, 정식은 2021년 9월 16일, 순환식 및 비순환식의 재 배 방식 적용은 2021년 10월 21일에 시행하였다. 배액 내 양 분 분석 결과, Na+와 Cl‒은 작물이 제대로 흡수하지 않는 대표 적은 이온으로써 생육이 진전될수록 순환식 재배방식에서 집 적되었다. 또한 배액 내 NH4-N의 함량이 NO3-N의 함량에 비 해 현저히 낮으므로 파프리카의 이온 선택성으로 인해 NO3-N 보다 NH4-N이 우선 흡수되는 것으로 생각된다. 파프리카의 생육 및 과실 특성은 배액 재사용 여부와 배지의 종류에 따른 처리 간의 차이가 크지 않았다. 결론적으로 순환식과 비순환 식의 수경재배 방식, 코이어와 암면의 배지 종류에 따른 파프 리카 수경 재배 시 중기 이후의 세력 약화로 인한 착과 불량을 유의하여 관리한다면 처리 간의 차이가 크지 않으므로 농가의 실정에 맞는 재배 방식과 배지를 선택하여 파프리카를 생산할 수 있을 것으로 생각된다. 다만 최근 환경오염에 대한 관심이 높아진 만큼 배액 재사용에 따른 병원균 감염 등을 잘 관리한 다는 가정 하에서 순환식 재배 방식을 채택해도 수량 감소나 품질 저하 등은 우려하지 않아도 될 것이라 판단되며, 폐기 문 제가 발생하는 암면 대신 코이어 배지를 선택한다면 더욱 환 경오염 감소에 기여할 수 있으리라 기대된다.
In general, after the decommissioning of nuclear facilities, buildings on the site can be demolished or reused. The NSSC (Nuclear Safety and Security Commission) Notice No. 2021-11 suggests that when reusing the building on the decommissioning site, a safety assessment should be performed to confirm the effect of residual radioactivity. However, in Korea, there are currently no decommissioning experiences of nuclear power plants, and the experiences of building reuse safety assessment are also insufficient. Therefore, in this study, we analyzed the foreign cases of building reuse safety assessment after decommissioning of nuclear facilities. In this study, we investigated the Yankee Rowe nuclear power plant, Rancho Seco nuclear power plant, and Hematite fuel cycle facility. For each case, the source term, exposure scenario, exposure pathway, input parameter, and building DCGLs were analyzed. In the case of source term, each facility selected 9~26 radionuclides according to the characteristics of facilities. In the case of exposure scenario, building occupancy scenario which individuals occupy in reusing buildings was selected for all cases. Additionally, Rancho Seco also selected building renovation scenario for maintenance of building. All facilities selected 5 exposure pathways, 1) external exposure directly from a source, 2) external exposure by air submersion, 3) external exposure by deposited on the floor and wall, 4) internal exposure by inhalation, and 5) internal exposure by inadvertent ingestion. For the assessment, we used RESRAD-BUILD code for deriving building DCGLs. Input parameters are classified into building parameter, receptor parameter, and source parameter. Building parameter includes compartment height and area, receptor parameter includes indoor occupancy fraction, ingestion rate, and inhalation rate, and source parameter includes source thickness and density. The input parameters were differently selected according to the characteristics of each nuclear facility. Finally, they derived building DCGLs based on the selected source term, exposure scenario, exposure pathway, and input parameters. As a result, it was found that the maximum DCGL was 1.40×108 dpm/100 cm2, 1.30×107 dpm/100 cm2, and 1.41×109 dpm/100 cm2 for Yankee Rowe nuclear power plant, Rancho Seco nuclear power plant, and Hematite fuel cycle facility, respectively. In this study, we investigated the case of building reuse safety assessment after decommissioning of the Yankee Rowe nuclear power Plant, Rancho Seco nuclear power plant, and Hematite fuel cycle facility. Source terms, exposure scenarios, exposure pathways, input parameters, and building DCGLs were analyzed, and they were found to be different depending on the characteristics of the building. This study is expected to be used in the future building reuse safety assessment after decommissioning of domestic nuclear power plants. This work was
Following a radioactive waste criterion and clearance level radioactive waste Act Article 2. “The radioactive wastes confirmed by the Commission as having concentration by nuclide not exceeding the value determined by the Commission through incineration, reclamation, recycling, etc”. The combustible clearance level radioactive wastes like lumbers are incinerated and non-combustible wastes like concreted are buried. The metals clearance level radioactive wastes are recycled after being re-molded. However, the clearance level radioactive waste with keeping its original forms is not common. Due to the nature of KAERI, the equipment are brought into the radiation-controlled zone for experiments. Those equipment are conservatively considered contaminated and categorized with radioactive waste following nuclear safety acts. In this case, the spectroscopy device which is clearance level radioactive waste is self-disposed for use in non-controlled areas. The 4 devices are composed of 3 gamma-ray spectroscopy and 1 alpha, beta counting system. Those devices were used for clearance level radioactive waste’s radioisotope analysis in Radioactive Waste Form Test Facility which is used in a separated room for analysis. This room will be released in nonradiation controlled area, therefore those devices will be moved to non-controlled area and keep using. Last April self-disposal was reported to the regulatory body and got acceptance last May. Those devices were moved to non-controlled area last July. This case will be good example for reuse equipment which stop using in radiation controlled area but can keep used.
본 연구에서는 하수 재이용을 위한 역삼투막 공정에서 전처리 정밀여과막(MF) 손상에 대한 누출되는 다양한 수 질변화로써 막 손상 검지 방안을 제시하였다. 이를 위하여 역삼투막 유입수질 적합성 평가지표인 SDI (silt density index)를 3에서 5의 범위 내에서 막 손상 시 검지 감도를 정량화하기 위하여 전처리 분리막이 1에서 3가닥 파단에 따라 SDI는 1.92에 서 6.11까지 증가한 결과를 확인할 수 있었다. 일반적으로 3을 기준으로 역삼투막 유입수질로 설정하였을 때 분리막이 3가닥 까지 파단이 되어야만 막 손상 검지가 가능하다는 것을 의미하며 역삼투막의 오염은 잠재적으로 가속화되어 효율을 저하시 킬 수 있다. 또한 이때 누출되는 입자성과 유기물질에 대하여 0.45 μm 이상의 크기만 걸러주는 입자계수는 입도분포별 막 파 단 개수에 따라 일정한 패턴을 확인할 수 없었으며, TOC 농도는 약 2배의 변화패턴으로써 SDI와의 상관관계로써 TOC가 막 손상 수질지표로써 신뢰성이 높은 것으로 확인되었다. 수질분석결과와 더불어 USEPA에서 제시하는 막 손상 검지 방법 중 압력손실시험과 이를 기반으로 LRVDIT 모델의 적합성 평가를 한 결과 막 손상 또는 역삼투막 공정으로 유입되는 막오염물질 을 신속하게 확인할 수 있는 SDI 및 TOC를 포함한 LRVDIT 모니터링과 UCL 설정을 병행해야 한다.
Decontamination and Dismantlement (D&D) are of great interest to owner of decommissioning as a large number of old nuclear facilities around the world are either shutdown or soon to be decommissioned. D&D are key steps in the decommissioning of nuclear power plants (NPPs). These activities typically generate a significant volume of radioactively contaminated waste. However, as much as 90% or more of this waste is lightly contaminated metal and concrete that could potentially be cleared for recycle or beneficial reuse, rather than disposed of as radioactive waste. The objective of this study is to provide reference for the application of current technologies to cost-effectively reduce the volume of radioactive waste associated with decommissioning, through review of experiences with decontamination of NPPs materials for unrestricted release, recycle or reuse, Also, highlights the importance of ongoing efforts to harmonize regulations and standards for radioactive waste management globally to enable reuse and recycle of valuable materials generated during decommissioning. The presented results in the balance of this study are organized to align with the sequence of operations for executing reuse or recycle of material for a decommissioning project. Concrete from buildings has most commonly been used for backfill of voids onsite, while metal has most commonly been melted or cleared into the conventional scrap recycling industry. Copper and lead, commonly found in cables and shielding, have high residual value and are thus highly desirable for recycling. Steel and stainless steel, while not inherently valuable, are present in many large components, such that decontamination for recycling can be cost-effective compared to disposal as radioactive waste. The decontamination techniques range from simple, inexpensive methods to complex, aggressive methods, each with advantages in various scenarios and limitations in others. Treatment often involves the sequential application of two or more decontamination techniques (e.g., chemical decontamination followed by abrasive blasting). Strategies for the characterization of materials for recycling include analyzing material in place before dismantlement, analyzing removed samples before or after dismantlement, and evaluating bulk material removed after dismantlement. If clearance and recycling are permitted, metals can be released to the conventional scrap recycling market, and concrete rubble can be used as backfill material onsite. In general, successful reuse/recycle projects require consideration of reuse/recycling objectives and implementation of associated planning activities early in the decommissioning process. The practicality of reuse/recycle depends on a number of high level (country and region-specific) and component level (material and case specific) factors. Since this information is useful to those responsible for planning or implementing the decommissioning of nuclear facilities, it is expected that it will be of great help especially to those in charge of decommissioning plan and managers in charge of decommissioning projects.
The radwaste facility management team is preparing for clearance of 4 MCAs in The Radwaste Form Test Facility (RFTF). The targeted waste was used for clearance level radioactive waste sample analysis and has been used for this purpose since the early 2000s. Due to the characteristics of clearance level radioactive waste, the concentration of radioactivity is very low and MCA is used with Marinelli beakers the possibility of contamination is low. Moreover, the radiation detector should not be contaminated with radioactive materials, it should be less than the clearance level. These detectors were considered surface contamination materials. To detect the contaminated spot of each material, we scanned the whole surface of a material with a gamma survey meter. After that, we took a sample from 1×1 m2 and a total of 30 samples from each MCA. The wiped filter paper was analyzed with alpha, beta low background counting systems. The results of the analysis of the smear sample of total alpha and beta nuclide radioactivity were less than MDA (α: 2.88×10−5 Bq·cm−2, β: 3.07×10−5 Bq·cm−2). The major nuclide in this facility is Co-60 and Cs-137 therefore we analyzed gamma nuclide activity with HPGe. The maximum specific activity was Co-60: 2.31×10−5 Bq·cm−2, Cs-137: 1.96×10−6 Bq·cm−2. If it is satisfied with the clearance criteria, detectors will be reused at the Radioactive Waste Treatment Facility (RWTF) room # 7251 uncontrolled area.
The purpose of this study was to effectively purify U-contaminated soil-washing effluent using a precipitation/distillation process, reuse the purified water, and self-dispose of the generated solid. The U ions in the effluent were easily removed as sediments by neutralization, and the metal sediments and suspended soils were flocculated–precipitated by polyacrylamide (PAM). The precipitate generated through the flocculation–precipitation process was completely separated into solid–liquid phases by membrane filtration (pore size < 45 μm), and Ca2+ and Mg2+ ions remaining in the effluent were removed by distillation. Even if neutralized or distilled effluent was reused for soil washing, soil decontamination performance was maintained. PAM, an organic component of the filter cake, was successfully removed by thermal decomposition without loss of metal deposits including U. The uranium concentration of the residual solids after distillation is confirmed to be less than 1 Bq·g−1, so it is expected that the self-disposal of the residual solids is possible. Therefore, the treatment method of U-contaminated soil-washing effluent using the precipitation/distillation process presented in this study can be used to effectively treat the washing waste of U-contaminated soil and self-dispose of the generated solids.
Due to the global climate change, Korean peninsula is has been experiencing flooding and drought severely. It is hard difficult to manage water resources sustainably, because due to intensive precipitation in short periods and severe drought has increased in Korea. Reused water from the wastewater treatment plant (WWTP) could be a sustainable and an alternative water source near the urban areas. In order to understand the patterns of water reuse in Korea, annual water reuses data according to the times and regional governments were investigated from 2008 to 2019. The reused water from WWTP in Korea has been mainly used for river maintenance flow and industrial use, while agricultural use of water reuse has decreased with time. Metropolitan cities in Korea such as Seoul, Busan, Daegu, Ulsan, and Incheon have been mainly used reused reusing water for river maintenance flow. Industrial water reuse has been limitedly applied recently for the planned industrial districts in Pohang, Gumi, Paju, and Asan. By using the collected annual water reuse data from the domestic sewerage statistics of sewerage, the optimistic and pessimistic future estimations of for future annual water reuse were suggested from 2020 to 2040 on a five year interval for every five years.