• Journal of Nuclear Fuel Cycle and Waste Technology
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• v.1 no.1
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• pp.83-92
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• 2013

A novel methodology to evaluate remote dismantling equipment for a reactor pressure vessel (RPV) in a decommissioning project is presented in this paper. The remote dismantling equipment, mainly composed of cutting tools and positioning equipment, is absolutely required to cut and handle highly radioactive and large components in nuclear power plants (NPPs); this equipment has a great effect on the overall success of the decommissioning project. Conventional evaluation methods have only focused on cutting technologies or positioning equipment, although remote dismantling equipment cannot achieve its goal without organic interaction between the cutting tools and the positioning equipment. In this paper, the cutting tools and the positioning equipment are evaluated by performance parameters according to their original characteristics, the relationship between the two systems, and common factors. Finally, the remote dismantling equipment used in recent decommissioning projects has been evaluated based on the proposed methodology. The results of this paper are expected to be useful for future decommissioning projects.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.194-195
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• 2021

Due to urban regeneration projects or changes in the living environment, there is an increasing need to demolish old buildings that have lost their functions. Demolition of above ground and underground structures is an important construction project that greatly affects the construction period and safety of the entire process. However, it is difficult for the safety officer to manage the demolition work due to the lack of specific and diverse data applicable to the site of the demolition plan. Therefore, in this study, items that need to be improved in structural safety when the above-ground and underground structures are demolished are reviewed and organized. For the main contents of structural safety management in demolition work, 1) structural review reflecting the order of demolition work, 2) installation and dismantling of steel pipe scaffolding and dust nets, 3) installation and dismantling of system scaffolding, 4) installation and dismantling of fall prevention nets, 5) jack support Installation and dismantling, 6) movement of equipment, movement and planning between floors, 7) equipment for demolition of structures, height of remnants, 8) site cleanup, and 9) equipment operators were categorized and arranged.

• Journal of the Korea Safety Management & Science
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• v.8 no.3
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• pp.67-75
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• 2006

Scheduling of dismantling old research reactor need to consider time, cost and safety for the worker. The biggest issue when dismantling facility for research reactor is safety for the worker and cost. Large portion of a budget is spending for the labor cost. To save labor cost for the worker, reducing a lead time is inevitable. Several algorithms applied to reduce read time, and safety considered as the most important factor for this project. This research presents three different dismantling scheduling scenarios. Best scenario shows the specific scheduling for worker and machine, so that it could save time and cost.

• Journal of Environmental Impact Assessment
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• v.30 no.4
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• pp.225-236
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• 2021

The master plan for the Four Rivers Restoration Project (June 2009) was devised, the procedure of pre-environmental review (June 2009) and environmental impact assessment (Nov. 2009), and post-environmental impact survey were implemented, and 4 times audits also inspected. and finally the Ministry of Environment's Four Rivers Investigation and Evaluation Planning Committee proposed the dismantling or partial dismantling of the five weirs of the Geum River and Yeongsan River. But controversies and conflicts are still ongoing. Therefore, this study intend to reestablish the management plan for the four major rivers by reviewing and analyzing the process so far. The results are as follows. First, a cost-benefit analysis should be performed by comparing the water quality impact of weir operation and weir opening. Therefore, it is inevitably difficult to conduct cost-benefit analysis. Second, according to the results of cost-benefit analysis on the dismantling of the Geum River and the Yeongsan River, the dismantling of the weir and the regular sluice gate opening was decided. However, there is a problem in the validity of the decision to dismantle the weir because the cost-benefit analysis for maintaining the weir is not carried out. Third, looking at the change in water quality of 16 weirs before and after the Four Major Rivers Restoration Project, COD and Chl-a were generally deteriorated, and BOD, SS, T-N, and T-P improved. However, in the cost-benefit analysis related to water quality at the time of weir dismantling, only COD items were targeted. Therefore, the cost of BOD, SS, T-N, and T-P items improved after the project were not reflected in the cost-benefit analysis of dismantling weirs, so the water quality benefits were exaggerated. Fourth, in the case of Gongju weir and Juksan weir, most of them are movable weirs, so opening the weir alone can have the same effect as dismantling when the water quality deteriorates. Since the same effect can be expected, there is little need to dismantle the weirs. Fifth, in order to respond to frequent droughts and floods, it is desirable to secure the agricultural water supply capacity to the drought areas upstream of the four majorrivers by constructing a waterway connected to the weir. At present it is necessary to keep weirs rather than dismantling them.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.498-499
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• 2018

• Nuclear Engineering and Technology
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• v.50 no.4
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• pp.606-612
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• 2018

Many nuclear power plants in Japan are approaching the end of their planned operational life spans. They must be decommissioned safely in the near future. Using augmented reality (AR), workers can intuitively understand information related to decommissioning work. Three-dimensional (work-site) reconstruction models of dismantling fields are useful for workers to observe the conditions of dismantling field situations without visiting the actual fields. This study, based on AR and work-site reconstruction models, developed and evaluated an information reference system. The evaluation consists of questionnaires and interview surveys administered to six nuclear power plant workers who used this system, along with a scenario. Results highlight the possibility of reducing time and mitigating mistakes in dismantling fields. Results also show the ease of referring to information in dismantling fields. Nevertheless, it is apparently difficult for workers to build reconstruction models of dismantling fields independently.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.3
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• pp.297-306
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• 2021

In this study, basic strategies for the decommissioning and site remediation of the Fukushima Daiichi Nuclear Power Station (FDNPS) were investigated. Six scenarios were formulated based on two of the three decommissioning strategies of nuclear power plants defined by the International Atomic Energy Agency (IAEA): immediate dismantling and deferred dismantling. A multicriteria decision analysis was performed to analyze the preferences of the options from the viewpoints of the timeframe to complete decommissioning, the resulting waste, the site usability, and the availability of the radioactive waste disposal route. The same six scenarios were applied to both the FDNPS and the nuclear power plants that ceased operation after a normal plant life cycle for comparison. For the FDNPS, the decommissioning project involved fuel debris retrieval, dismantling, and site remediation. The analysis results suggest that the balance between the amount of waste and the time to achieve the end state may be one of the most critical factors to consider when planning the decommissioning and site remediation of the FDNPS.

• Korean Journal of Construction Engineering and Management
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• v.9 no.5
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• pp.104-115
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• 2008

Currently, reconstruction and remodeling are conducted to improve the performance of aged housing. Recently reconstruction has caused many problems such as wastes generation, wasting resources and real estate speculation, remodeling is drawing attention. Accordingly, remodeling business for aged housings gradually increasing, but the use of scheduling method not considering characteristics of remodeling deters construction in some construction types. Especially, in case of dismantling construction, the dismantling is delayed since the scheduling method not considering characteristics of remodeling is used. In case of remodeling, dismantling construction is ahead of other processes, if the dismantling construction is delayed, whole construction will be delayed and if speedy construction is conducted, the costs for remodeling will increase. Furthermore, existing remodeling for aged housing has been for rahmen(crossbeam and pillar) structure apartments, but since most apartments to be remodeled are wall-slab structure where dismantling takes a lot of weight, it is highly possible the dismantling construction is delayed. Thus, this paper is to establish scheduling method for the dismantling construction reflecting characteristic of remodeling to prevent delay of dismantling construction for remodeling of aged housing with wall-slab structure.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.671-675
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• 2003

In accordance with the KRR-1 & 2 decommissioning project, the decontamination and dismantling activities of the KRR-2 auxiliary facilities, radioisotope production facilities, were completed from Aug 2001 to Dec 2002. The auxiliary facilities were composed of the concrete hot-cell, lead hot-cells and several laboratories for the radioisotope production. The dismantling objects are home hoods, experimental desks, sinks, and contaminated inner facilities. For the purpose of the safe decommissioning activity, the method statements and working procedures were set up. The manpower of the total 20,933 man-hour was required and several dismantling equipments were also. The maximum surface contamination is: 9.24 Bq/$\textrm{cm}^2$ in removable contamination and 350,000 cpm in fixed contamination. The total amount of 62.146 Ton was raised as dismantled waste with kinds of the concretes, wood, steels, etc. The collective dose was evaluated as 0.33 mam-mSv during this period.

• Journal of Digital Convergence
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• v.16 no.1
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• pp.317-325
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• 2018

A satisfactory ending of the project is crucial for the students to achieve success experience. In this study, we analyze the teams' dismantling before the project deadline. We propose a team dissolution model based on the assumption that the disharmony caused by the members' personality traits is the main reason for the team break up. The Dark Triad and the Communion are introduced to build the model. We simulated the proposed model using an agent-based simulation and analyzed the results. We found that the ratio of owning DT impacts the maximum allowable size of the team and the team's rate of dissolution, but the team has been able to reduce the team's dissolution rate by increasing the team's harmony. We expect that we efficiently used the developed model with the agent-based simulation for the studies related to the dismantling of teams.