PURPOSES : This study presents an application plan for parking spaces for shared e-scooters using the clearance widths of sidewalks. The detailed purposes are as follows: firstly, to present appropriate spaces for installing parking lots for shared E-scooters. Secondly, to derive the specifications of parking unit spaces for shared E-scooters. Thirdly, to derive the formula for calculating the parking angle of shared E-scooters. Lastly, to provide examples of calculating the parking angle using the derived formula. METHODS : Based on the literature review, appropriate locations for installing parking spaces for shared E-scooters on sidewalks were proposed. We also investigated design factors based on a literature review to derive the specifications of parking unit spaces for shared E-scooters, and utilized the geometric characteristics of clearance widths of sidewalks to derive a formula for calculating the parking angle. Finally, we provide examples of calculating the parking angle for shared E-scooters using the derived formula. RESULTS : The results of this study are as follows. We proposed clearance widths of sidewalks as appropriate spaces for installing parking spaces for shared E-scooters. Next, we derived the specifications of parking unit spaces for shared E-scooters considering anthropometric measurements, specifications of shared E-scooters, and clearance dimensions. Moreover, we derived a formula for calculating the parking angle of shared E-scooters considering clearance widths of sidewalks. Finally, we presented examples of calculating the parking angle for shared E-scooter parking unit spaces based on clearance widths of sidewalks. CONCLUSIONS : It was concluded that the application for parking spaces for shared e-scooters using the clearance widths of sidewalks was presented. We derived the standard and compact specifications of parking unit spaces for shared E-scooters, and provided foundational data for estimating the parking capacity using a formula for calculating the parking angle of shared E-scooters. Future research directions include presenting case studies of estimating parking capacity using the parking angle of shared E-scooters.
PURPOSES : This study aimed to identify factors affecting the duration of traffic incidents in tunnel sections, as accidents in tunnels tend to cause more congestion than those on main roads. Survival analysis and a Cox proportional hazards model were used to analyze the determinants of incident clearance times. METHODS : Tunnel traffic accidents were categorized into tunnel access sections versus inner tunnel sections according to the point of occurrence. The factors affecting duration were compared between main road and tunnel locations. The Cox model was applied to quantify the effects of various factors on incident duration time by location. RESULTS : Key factors influencing mainline incident duration included collision type, driver behavior and gender, number of vehicles involved, number of accidents, and post-collision vehicle status. In tunnels, the primary factors identified were collision type, driver behavior, single vs multi-vehicle involvement, and vehicles stopping in the tunnel after collisions. Incidents lasted longest when vehicles stopped at tunnel entrances and exits. In addition, we hypothesize that incident duration in tunnels is longer than in main roads due to the reduced space for vehicle handling. CONCLUSIONS : These results can inform the development of future incident management strategies and congestion mitigation for tunnels and underpasses. The Cox model provided new insights into the determinants of incident duration times in constrained tunnel environments compared to open main roads.
The nuclear facilities at Korea Atomic Energy Research Institute (KAERI) have generated a variety of organic liquid radwaste and radiation levels are also varied. At KAERI, the organic liquid radwaste has been stored at Radioactive Waste Treatment Facility (RWTF) temporarily due to the absence of the recognized treatment technique while inorganic liquid radwaste can be treated by evaporation, bituminization, and solar evaporation process. The organic liquid radioactive waste such as spent oil, cutting oil, acetone, ethanol, etc. was generated from the nuclear facilities at KAERI. Among the organic liquid radioactive wastes, spent oil is particularly significant. According to the nuclear safety act, radioactive waste can be cleared by incineration and landfilling if it meets the criteria of less than 10 μSv/h for individual dose and 1 person – Sv/y for collective dose. Dose assessment was performed on some organic liquid radioactive waste with a very low possibility of radioactive contamination stored in RWTF at KAERI. As a result, it was confirmed that some wastes met the regulatory clearance standards. Based on this, it was approved by the regulatory body, and this became the first case in Korea and KAERI for permission for regulatory clearance of organic liquid radioactive waste by landfill after incineration.
The radioactive waste generated within radiation-controlled areas is classified and processed according to relevant laws and regulations based on contamination levels. In cases where such radioactive waste complies with the legally defined clearance concentration or dose criteria, it is disposed of as non-radioactive waste by means of incineration, reclamation, recycling, etc. Within radiation controlled areas, various consumables are periodically replaced to ensure the proper operation of the area. It is necessary to have appropriate disposal methods for these consumables. In particular, waste items such as fire extinguishers, fluorescent lamps, batteries, and pressure vessels (hereinafter referred to as “Special Waste Type”), which may contain hazardous substances within their internal components and contents, should be considered for appropriate disposal methods that comply with nuclear safety and environmental laws. In the present case, the specified special waste type do not come into direct contact with radiation sources, and they have impermeable surfaces, which significantly reduces the risk of external contamination infiltrating the interior. However, the current method of clearance is not suitable for these items (Typically, nuclear energy-related business operators are required to classify clearance target waste based on internal and external components and demonstrate compliance with the criteria. Nevertheless, for special waste type, it is difficult to separate and measure internal and external components within the radiation-controlled area). In this case, the Clearance Procedure for special waste type applied to Korea Atomic Energy Research Institute was introduced. Additionally, we have extracted considerations for future domestic clearance of the type.
Large amounts of concrete, metal, soil, and other radioactive waste are generated not only from nuclear power plants operating in Korea but also from nuclear power plant decommissioning. If it is confirmed through measurement of residual radioactivity that the concentration is below the allowable clearance level, they can be managed as general or industrial waste in accordance with the Nuclear Safety Act. The Korea Radioactive Waste Agency predicts that very low-level radioactive waste will be generated the most, at about 67.1%. If waste below clearance level among very low-level radioactive waste can be evaluated and reduced, a lot of costs can be saved. Among radioactive wastes, metal wastes in particular have various sizes, shapes, and densities. If radioactivity is measured without properly considering this, a large error occurs in the measured value even if the radioactivity value is the same. This requires a conservative measurement method using density correction taking into account the self-absorption effect. For conservative measurements, it is essential to compare measured values with calculated values using MCNP6 (Monte Carlo N-Particle). You must enter the geometry of the measurement environment and derive calculated values using F8 Tally. Clearance level of radioactive waste is determined through the above method. In addition, sufficient MDA (Minimum Detectable Activity) must be secured to determine clearance level by using NaI(Tl), plastic scintillator configuration, and lead shielding. Nuclide analysis is performed using a NaI(Tl) scintillator and the total gamma radioactivity is evaluated using a highly efficient plastic scintillator.
The decommissioning of Korea Research Reactor Units 1 and 2 (KRR 1&2), the first research reactors in South Korea, began in 1997 and the decommissioning status is currently proceeding with phase 3. It is expected that more than 5,000 tons of dismantled wastes will be generated as the contaminated building is demolished. Since these dismantled wastes must be disposed of in an efficient method considering economic feasibility, it is desirable to clearance extremely low-level wastes whose contamination is so minimal that the radiological risk is negligible. In Korea, in order to approve the clearance of radioactive waste, it must be proven that the nuclide concentration standards are met or that the dose to individuals and collectives is below the allowable dose value. At the KRR 1&2 decommissioning site, dismantled wastes have been steadily being disposed of through clearance procedure since 2021. Clearance was approved by the Korean Institute of Nuclear Safety (KINS) for one case of concrete waste in 2021 and two cases of metal waste in 2022. In 2023, the clearance of metal waste and asbestos waste has been approved so far, and in particular, this is the first case in Korea for asbestos waste. In this study, we compared the dose assessment methods and results of clearance wastes at the KRR 1&2 decommissioning site from 2021 to present. Dose assessment was conducted by applying the landfill scenario for concrete and asbestos and the recycling scenario for metal waste. The calculation codes used were RESRAD-onsite 7.2 and RESRAD-recycle 3.10. The dose conversion factors (DCF) for each age group (infant, 1y, 5y, 10y, 15y, adult) of the target nuclide used the values presented in ICRP-72, and in particular, geo-hydrological data of the actual landfill site was used as an input factor when evaluating landfill scenarios. As a result of the dose assessment, when landfilling concrete wastes in 2020, the personal dose and collective dose were evaluated the most at 2.80E+00 μSv/y and 4.83E-02 man·Sv/y, respectively.
There is a large amount of radioactive waste in waste storage in the Korea Atomic Energy Research Institute. Some of the radioactive waste was generated during the dismantling process due to Korea Research Reactor 1&2 and it accounts for 20% of the total waste. Radioactive waste must be reduced by appropriate disposal methods to secure storage space and to reduce disposal costs. Research Reactor wastes include wastes that are below the acceptable criteria for selfdisposal and non-contaminated wastes, so they can be treated as wastes subject to self-disposal through contamination analysis and reclassification. In order to deregulation radioactive waste, it is necessary to meet the self-disposal standards stipulated in the Domestic Nuclear Act and the treatment standards of the Waste Management Act. The main factors of deregulation are surface contaminant, radionuclide activity and dose assessment. To confirm the contamination of waste, surface contaminant and gamma nuclide analysis were performed. After homogenizing the waste sample, it was placed in 1 L Mariinelli beaker. When collecting waste samples, 1 kg per 200 kg of waste was collected. The concentrations of the major radionuclides Co-60, Cs-134, Cs-137, Eu-152, and Eu-154 were analyzed using HPGe detector. To evaluate radiation dose, various computational programs were used. A dose assessment was performed with the analyzed nuclide concentration. The concentrations of representative nuclides satisfied the deregulation acceptance criteria and the results of the dose assessment corresponding to self-disposal method was also satisfied. Based on this results, KAERI submitted the report on waste self-disposal plan to obtain approval. After final approval, Research Reactor waste is to be incinerated and incineration ash is to be buried in the designated place. Some metallic waste has been recycled. In this study, the suitability of deregulation for self-disposal was confirmed through the evaluation of the surface contaminant analysis, radionuclide concentration analysis and dose assessment.
In the decommissioning site of Korean Research Reactor 1&2 (KRR-1&2), according to Low and Intermediate-level Radioactive Waste Disposal Acceptance Criteria of the Korea Radioactive Waste Agency (WAC-SIL-2022-1), characteristics of radioactive waste was conducted on approximately 550 drums of concrete and soil waste for a year starting from 2021. Among them, 50 drums of concrete waste transported and disposed to Gyeongju LILW disposal facility at the end of 2022. For the remaining approximately 500 drums of concrete and soil waste stored on-site, they were reclassified into two categories: permanent disposal grade and clearance grade. This classification was based on calculating the sum of fractions (SOF) per drum for each radionuclides. The plan is to dispose of around 200 drums in the permanent disposal grade and about 300 drums in the clearance grade by the end of 2023. Since concrete and soil decommissioning wastes are generated in large quantities over a short period with similar origins, they were grouped within five drums as suggested by the acceptance criteria. Mixed samples were collected from each group and used for radionuclide analysis. When utilizing mixed samples, three distinct samples are collected and analyzed for each group. The maximum value among these three radionuclide analysis results is then uniformly applied as the radionuclide concentration value for all drums within that group. Radioactive nuclides contained in similar types of radioactive waste with similar origins can be expected to have some statistical distribution. However, There has been no verification as to whether the maximum value among the three mixed samples exists within the statistical distribution or if it deviates from this distribution to represent a different value. In this study, we confirmed characteristics of radionuclide concentration distribution by examining and comparing radionuclide concentration distributions for radioactive wastes drum grouped for nuclear characteristic among 50 concrete wastes drum disposed in year 2022 and 500 concretes & soils drum scheduled for disposal (clearance or permanent disposal) in year 2023. In particular, when comparing tritium to other nuclides, it was observed that the standard deviation for the distribution of maximum values was approximately 318 times larger.
Anthropomorphism is a prevalent marketing practice that fosters consumer perceptions of a brand as humanlike. In today’s hyperconnected marketplace, firms are increasingly imbuing their brands with human features with the hope that the favorable perceptions of humanlike attributes in nonhuman objects could lead to consumers’ positive evaluation of humanized products. For example, Amazon has imbued Echo, a voice-activated Bluetooth speaker, with the human name Alexa, a female voiced virtual assistant that employs familiar human speech pattern, and some advanced personality traits. Similarly, Hormel Foods has used Mr. Peanut, the advertising logo and mascot of Planters that embodies the brands’ selling points. Mr. Peanut is depicted as a humanized peanut with arms, legs, top hat, and monocle and became a vessel of brand meaning and personality, taking on the product quality that the brand aims to communicate. Prior studies that use brand anthropomorphism as a foundation have investigated the impact of brand anthropomorphism on various outcomes such as product evaluations, emotional responses, and intentions to replace a product. However, what is missing from prior work is an understanding of the impact of brand anthropomorphism on the purchase intentions for clearance products which are sold under a retailer’s promotional strategy as an inventory management tool. The lure of cheapened goods may expand the range of consumers who can afford to buy merchandise from the company or may provide existing customers with an appealing purchasing option. In light of this, clearance sales are known to be effective not only for increasing store traffic by alluring price-conscious consumers but also for reducing excess inventory in a retail location or a chain of product fulfillment. The strategic importance of clearance sales has increased since the breakdown of COVID-19 which forced retailers to close their stores and caused demand for many product categories to plunge in early 2020. After the initial shock of the pandemic, consumer spending recovered fairly quickly, giving rise to record levels later in the same year. This surprising recovery continued into the next year as consumer sentiment and spending levels surged together, resulting in consumer demand that surpassed retailers’ stock levels. However, due to inflation and amounting fears of recession, consumer spending started to slow down again in 2022, resulting in the opposite of what happened in the previous year. Such a reversal caused many retailers to face high inventory levels and declining profitability, forcing them to cut prices to move excess inventory out of stores, which increases the importance of conducting clearance sales effectively. Clearance sales are prevalent in retail markets, where considerable discounts are typically offered for leftover items (Zhang & Cooper, 2008). Retailers widely use clearance sales to liquidate their unsold products at the end of a selling season (Nocke & Peitz, 2007). They have strong incentives to get rid of the remaining items in order to make room for the new products (Sällström, 2001). Previous research suggests that anthropomorphism leads consumers to apply human schema to a product, which in turn affects their attitude toward the product (Aggarwal & McGill, 2007, 2012). In this research, we aim to identify the negative effect of anthropomorphism on consumers’ attitude toward clearance products.
Natural uranium-contaminated soil in Korea Atomic Energy Research Institute (KAERI) was generated by decommissioning of the natural uranium conversion facility in 2010. Some of the contaminated soil was expected to be clearance level, however the disposal cost burden is increasing because it is not classified in advance. In this study, pre-classification method is presented according to the ratio of naturally occurring radioactive material (NORM) and contaminated uranium in the soil. To verify the validity of the method, the verification of the uranium radioactivity concentration estimation method through γ-ray analysis results corrected by self-absorption using MCNP6.2, and the validity of the pre-classification method according to the net peak area ratio were evaluated. Estimating concentration for 238U and 235U with γ-ray analysis using HPGe (GC3018) and MCNP6.2 was verified by -spectrometry. The analysis results of different methods were within the deviation range. Clearance screening factors (CSFs) were derived through MCNP6.2, and net peak area ratio were calculated at 295.21 keV, 351.92 keV(214Pb), 609.31 keV, 1120.28 keV, 1764.49 keV(214Bi) of to the 92.59 keV. CSFs for contaminated soil and natural soil were compared with U/Pb ratio. CSFs and radioactivity concentrations were measured, and the deviation from the 60 minute measurement results was compared in natural soil. Pre-classification is possible using by CSFs measured for more than 5 minutes to the average concentration of 214Pb or 214Bi in contaminated soil. In this study, the pre-classification method of clearance determination in contaminated soil was evaluated, and it was relatively accurate in a shorter measurement time than the method using the concentrations. This method is expected to be used as a simple pre-classification method through additional research.
The concept of clearance is to manage radioactive waste by incineration, reclamation, or recycling as non-radioactive waste, excluding those found to have a concentration of less than the allowable concentration of clearance. Among the types of waste subject to clearance, concrete is managed by recycling and landfill, metal by recycling and reuse, combustible materials by incineration, and soil by landfill. In Korea, clearance has been implemented in earnest since 2000, and the types and quantity of waste subject to clearance are increasing. For clearance, the nuclear-related operator submits its clearance plan to the regulatory body, and the regulatory body reviews the clearance plan and notifies the operator of its suitability. Since a significant amount of radioactive waste generated when decommissioning nuclear power plants is expected to be classified as clearance waste, this study will present clearance waste disposal measures for nuclear power plant through a review of overseas cases related to clearance.
The operation and decommissioning of nuclear power plants (NPPs) creates waste in the process of handling radioactively contaminated material, which must be disposed of in a repository or can be recovered of in the same way as conventional waste in the course of handling radioactively contaminated materials. For buildings or sites of NPPs it also has to be decided under what conditions they can continue to be used for other, conventional purposes or demolished. This decision is referred to as “release from supervision under nuclear and radiation protection law” or “clearance” in short. The clearance levels applicable in Germany according to the Radiation Protection Ordinance have been defined such that a radiation dose (hereinafter referred to as “dose”) of 10 μSv per year is not exceeded. The vast majority of the materials resulting from the dismantling of a nuclear power plant (e.g. most of the massive concrete structures) are neither contaminated nor activated. Thus, there is no need to treat these materials as radioactive waste. Emplacement of uncontaminated masses which in Germany is essentially several million tonnes of building rubble in a repository would require additional construction of such facilities, which, in view of the negligible hazard potential, from the point of view of the Nuclear Waste Management Commission (ESK) is clearly to be rejected both economically and, in particular, ecologically. Alternative ways are increasingly discussed in public, such as the abandonment of buildings after gutting, i.e. refraining from demolition of the controlled area buildings of NPPs. Also, another proposal discussed in public, the landfilling or the long-term storage of cleared material at the site, does not offer any safety-related advantages either in the view of the ESK. If, after completion of all dismantling work, the building has been decontaminated such that the clearance levels for buildings are complied with further use of the building rubble resulting from demolition is harmless from a radiological point of view. For these reasons, Germany has deliberately decided to use clearance as an essential measure in the dismantling of NPPs. If it is intended to conventionally reuse or depose of virtually contaminant-free material from controlled areas, it must first undergo a clearance procedure. The prerequisites that must be fulfilled for clearance are regulated in the Radiation Protection Ordinance, which includes two basic clearance pathways: unrestricted and specific clearance. In the following, the basic process of clearance is briefly presented and illustrated for a better understanding. It comprises five steps. Step 1-Radiological characterization by sampling, Step 2-Dismantling of plant components in the controlled area, Step 3- Decontamination, Step 4-Decission measurements, Step 5-Clearacnce and further management. The entire clearance process is governed by a clearance notice and is carried out under the supervision of the competent authority under nuclear and radiation protection law or the independent authorized expert commissioned by it. The clearance pathways contained in the Radiation Protection Ordinance have proven themselves in practice. They permit safe and proper management of material from dismantling and release of the site from supervision under nuclear and radiation protection law. These German regulatory procedures should be taken into account and deregulation and removal should be used as appropriate and necessary tools in the process of decommissioning NPPs in order to return non-hazardous materials to the material cycle or for conventional disposal.
The types of waste generated in radiation controlled areas of nuclear facilities are very diverse. Among them, the waste containing hazardous materials such as electrical equipment and fire safety equipment that do not directly handle radioactive materials is also primarily classified as radioactive waste because it was used and stored in the radiation controlled area. Such wastes include periodic consumables such as fluorescent lamps, fire extinguishers, batteries, and gas containers after use. The waste is ambiguous and cannot be easily treated as radioactive waste or waste subject to clearance, and has been stored in a radiation controlled area for a long time, and the amount is continuously increasing. The storage space is saturated and has difficulty in management. IAEA ISO-7503-2016 clearly states that surface contamination measurement can be applied to surface contamination substrates (impermeable, non-activated) instead of volume contamination measurement. In order to solve these concerns, some facilities within the Korea Atomic Energy Research Institute were selected to explore self-disposal methods based on surface contamination in consideration of the characteristics of waste and facility contamination. The surface contamination degree and qualitative gamma spectroscopic analysis were carried out by the method. First, we examined the characteristics of the facility, the history of the air pollution level of the usage/storage space, and periodic inspection records. Second, we measured the physical properties (area/weight) of the waste in the same treatment way as the existing waste. Third, gamma dose rate and surface contamination (direct/indirect method) are measured for the entire area to confirm contamination is possible. It was confirmed that the concentration standard was satisfied. In order to clarify the presence of contamination, a qualitative method of gamma nuclide analysis was also performed. All surveys/measurements of 4 types of waste at 7 facilities were performed and it was confirmed that all waste satisfies the permissible concentration standard for clearance which conservatively set at 0.1 Bq/g as the permissible concentration standard. In the future, We hope that you will use this as a reference to search for easier disposal methods for regulatory bodies and specified waste disposal methods, and contribute to reducing the amount of radioactive waste generated.
It is important to make a strategy for clearance-level radioactive waste. Sampling and disposal plans should be drawn up with characteristics of target waste. In this paper, a target clearance-level radioactive waste is used in a laboratory for experiments with Cs-137 and Co-60, unsealed radioactive sources with gamma radiation isotopes. Therefore, it is enough to analyze with HPGe to check the contaminant level. The laboratory fume hood combined multiple materials, which means some are volume contamination and others are surface contamination. The wood, plastic, and drywall boards, which are absorbent volume contaminated parts and make up PVC pipes, base cabinet doors, backside baffles, etc., will be sampled with coring methods. The metals and glasses, which are unabsorbent, surface-contaminated parts, are sampled with smear methods. The work surface, baffles, exhaust plenum, and glass sash inside parts have a high possibility of being contaminated. The hood body, flame, base cabinet, PVC pipe (the rare end of the filter), and blower transition case have a low possibility of becoming contaminated. When we checked with HPGe, except for the work surface (which was below clearance level), other parts were less than MDA. The highest radionuclide concentration was in PVC pipe: Cs-137C 3.91E-02 (Bq/g), Co-60 4.54E- 03 (Bq/g). It is less than clearance level. Therefore, the waste was applied for the clearance level radioactive wastes and got permission from the regulatory body.