• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.275-276
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• 2017

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.235-236
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• 2018

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.52-62
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• 2023

Various decontamination technologies have been developed for removing contaminated areas in industries. Although it is important to consider parameters such as safety, cost, and time when selecting the decontamination technology, till date their comparative study is missing. Furthermore, different decontamination technologies influence the decontamination effects in different ways. Therefore, this study compares different decontamination techniques for the steam generator using a multicriteria decision-making method. A steam generator is a large device comprising both low- and very low-level waste (LLW, VLLW) and reflects the difference in weights of the standards according to the classification of the waste. For LLW and VLLW decontaminations, chemical oxidizing reduction decontamination (CORD) and decontamination grit blasting were used as the preferred techniques, respectively, considering the purpose of decontamination differs based on the initial state of waste. An expert survey revealed that safety in LLW and waste minimization in VLLW exhibited high preference. This evaluation method can be applied not only to the comparison between each process, but also to the creation of process scenarios. Therefore, determining the decontamination approach using logical decision-making methods may improve the safety and economic feasibility of each step in the decommissioning process and ensure a public acceptance.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.1
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• pp.45-55
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• 2016

Decontamination is one of the most important technologies for the decommissioning of NPP. The purpose of decontamination is to reduce the Risk of exposure of the decommissioning workers, and to recycle parts of the plant components. Currently, there is a lack of data on the efficiency of the decontamination technologies for decommissioning. In most cases, the local radiation level can be lowered below a regulatory limitation by decontamination. Therefore, more efficient decontamination technology must be continuously developed. This work describes the practical experiences in the United States and the European countries for NPP decommissioning using these decontamination technologies. When the decommissioning of domestic nuclear power plant is planned and implemented, this work will be helpful as a reference of previous cases.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.1
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• pp.51-58
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• 2021

Chemical decontamination of primary systems in a nuclear power plant (NPP) prior to commencing the main decommissioning activities is required to reduce radiation exposure during its process. The entire process is repeated until the desired decontamination factor is obtained. To achieve improved decontamination factors over a shorter time with fewer cycles, the appropriate flow characteristics are required. In addition, to prepare an operating procedure that is adaptable to various conditions and situations, the transient analysis results would be required for operator action and system impact assessment. In this study, the flow characteristics in the steady-state and transient conditions for the chemical decontamination operations of the Kori-1 NPP were analyzed and compared via the MARS-KS code simulation. Loss of residual heat removal (RHR) and steam generator tube rupture (SGTR) simulations were conducted for the postulated abnormal events. Loss of RHR results showed the reactor coolant system (RCS) temperature increase, which can damage the reactor coolant pump (RCP)s by its cavitation. The SGTR results indicated a void formation in the RCS interior by the decrease in pressurizer (PZR) pressure, which can cause surface exposure and tripping of the RCPs unless proper actions are taken before the required pressure limit is achieved.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.33-38
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• 2005

The distribution of vanadium and iron ionic species in the presence of picolinate ligand has been simulated at various conditions with different pH values and compositions in the decontamination waste solution. In spite of variations of metal concentration in the decontamination solution, the shape of distribution diagrams were not changed greatly at both high (the molar ratio of picolinate to vanadium is 6) and low (the molar ratio is 3) LOMI decontamination conditions. However, in the solution of low-picolinate condition the shape of the distribution diagram of iron(II)-picolinate complexes was changed significantly. This phenomenon is attributed to the shortage of relative amount of picolinate ligand to iron existed in the solution, and originated from the difference in stability constants for complexes formed between vanadium(III) and iron(II) species with picolinate ligand. The distribution diagrams obtained in this study can be applied very usefully to the prediction or understanding the reaction phenomena occurred at various conditions in the course of the LOMI waste treatments such as an ion exchange operation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.3
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• pp.187-199
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• 2015

Decontamination is one of the crucial technologies that are applied during the decommissioning process of nuclear facilities to secure the safety of workers and to minimize the quantity of radioactive waste. Decontamination removes radionuclides on the surface of contaminated metal. Compared with decontamination for operational nuclear facilities, decontamination for nuclear power plants that are being decommissioned needs to remove the more and thicker surface using more aggressive agents or specially developed equipment. This paper analyzed the factors to be considered before planning the decontamination, representative decontamination technologies, and their application procedure,etc. ORCID

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.289-295
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• 2016

Kori Unit 1, the first PWR (Pressurized Water Reactor) plant in Korea, began its commercial operation in 1978 and will permanently shut down on June 18, 2017. After moving the spent fuels to SFP (Spent Fuel Pool) system, Kori Unit 1 will perform a full system chemical decontamination to reduce radiation levels inside the various plant systems. This paper will describe the operation concept of the full system chemical decontamination for Kori Unit 1 based on experiences overseas.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.05a
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• pp.338-339
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• 2017

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.720-724
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• 2003

In order to develop the decontamination process for self-disposal with authorization of duct waste generated from the decommissioning of retired TRIGA research reactors, the surface characterization of duct specimen taken from TRIGA research reactor was carried out and the adequate decontamination method was selected. It can be known that the paint coated internal surface of duct is contaminated with $^{60}Co$and $^{137}Cs$, which are penetrated into the paint layer and incorporated into zinc plated surface of galvanized iron as the material of duct. Two step chemical decontamination process, in which sodium hydroxide and sulfuric acid solutions are used in turn, is quite successful to remove the surface contamination of duct waste.