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Prof. Jae Hak Cheong
Kyung Hee University

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0 Decommissioning
0 Radioactive Waste Management
0 Spent Nuclear Fuel
0 Effluents
0 safety assessment

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Journal article
Published: 25 August 2021 in Chemosensors
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Plastic scintillators are widely used in various radiation measurement applications, and the use of plastic scintillators for nuclear applications including decommissioning, such as gamma-ray detection and measurement, is an important concern. With regard to efficient and effective gamma-ray detection, the optimization for thickness of plastic scintillator is strongly needed. Here, we elucidate optimization of the thickness of high-performance plastic scintillator using high atomic number material. Moreover, the EJ-200 of commercial plastic scintillators with the same thickness was compared. Two computational simulation codes (MCNP, GEANT4) were used for thickness optimization and were compared with experimental results to verify data obtained by computational simulation. From the obtained results, it was confirmed that the difference in total counts was less than 10% in the thickness of the scintillator of 50 mm or more, which means optimized thickness for high efficiency gamma-ray detection such as radioactive 137Cs and 60CO. Finally, simulated results, along with experimental data, were discussed in this study. The results of this study can be used as basic data for optimizing the thickness of plastic scintillators using high atomic number elements for radiation detection and monitoring.

ACS Style

Sujung Min; Youngsu Kim; Kwang-Hoon Ko; Bumkyung Seo; Jaehak Cheong; Changhyun Roh; Sangbum Hong. Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study. Chemosensors 2021, 9, 239 .

AMA Style

Sujung Min, Youngsu Kim, Kwang-Hoon Ko, Bumkyung Seo, Jaehak Cheong, Changhyun Roh, Sangbum Hong. Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study. Chemosensors. 2021; 9 (9):239.

Chicago/Turabian Style

Sujung Min; Youngsu Kim; Kwang-Hoon Ko; Bumkyung Seo; Jaehak Cheong; Changhyun Roh; Sangbum Hong. 2021. "Optimization of Plastic Scintillator for Detection of Gamma-Rays: Simulation and Experimental Study." Chemosensors 9, no. 9: 239.

Review
Published: 11 June 2021 in Sensors
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Herein, we review studies of the integration of Phoswich detectors with readout integrated circuits and the associated performance in a radiological sensing application. The basic concept and knowledge of interactions with scintillation materials and the mechanisms and characteristics of radiological detection are extensively discussed. Additionally, we summarize integrated multiple detection systems and Phoswich detectors in radiological measurements for their device performance. Moreover, we further exhibit recent progress and perspective in the future of Phoswich-based radiological detection and measurement. Finally, we provide perspectives to evaluate the detector performance for radiological detection and measurement. We expect this review can pave the way to understanding the recent status and future challenges for Phoswich detectors for radiological detection and measurement.

ACS Style

Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. Phoswich Detectors in Sensing Applications. Sensors 2021, 21, 4047 .

AMA Style

Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jaehak Cheong. Phoswich Detectors in Sensing Applications. Sensors. 2021; 21 (12):4047.

Chicago/Turabian Style

Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. 2021. "Phoswich Detectors in Sensing Applications." Sensors 21, no. 12: 4047.

Journal article
Published: 04 June 2021 in Applied Sciences
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The highly reliable and direct detection of radioactive cesium has gained potential interest due to in-situ detection and monitoring in environments. In this study, we elucidated an integrated and portable probe based on functional plastic scintillator for detection of radioactive cesium. A functional plastic scintillator with improved detection efficiency was fabricated including CdTe (cadmium telluride) material. Monolith-typed functional plastic scintillator having a diameter of 50 mm and a thickness of 30 mm was manufactured by adding 2,5-diphenyloxazole (PPO, 0.4 wt%), 1,4 di[2-(5phenyloxazolyl)]benzene (POPOP, 0.01 wt%), and CdTe (0.2 wt%) materials in a styrene-based matrix. To evaluate the applicability of the plastic scintillator manufactured to in-situ radiological measurement, an integrated plastic detection system was created, and the measurement experiment was performed using the Cs-137 radiation source. Additionally, detection efficiency was compared with a commercial plastic scintillator. As results, the efficiency and light yield of a functional plastic scintillator including CdTe were higher than a commercial plastic scintillator. Furthermore, the remarkable performance of the functional plastic scintillator was confirmed through comparative analysis with Monte Carlo simulation.

ACS Style

Sujung Min; Hara Kang; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium. Applied Sciences 2021, 11, 5210 .

AMA Style

Sujung Min, Hara Kang, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jaehak Cheong. Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium. Applied Sciences. 2021; 11 (11):5210.

Chicago/Turabian Style

Sujung Min; Hara Kang; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jaehak Cheong. 2021. "Integrated and Portable Probe Based on Functional Plastic Scintillator for Detection of Radioactive Cesium." Applied Sciences 11, no. 11: 5210.

Research article
Published: 03 May 2021 in Science and Technology of Nuclear Installations
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An optimal long-term electric power strategy for Saudi Arabia to adopt nuclear power was evaluated using the MESSAGE tool. Saudi Arabia is predicted to experience an electricity shortage by 2025 with the present energy system. This electricity shortage could be postponed until 2035 by rehabilitating the existing power plants. The MESSAGE model predicts that adopting a combination of renewable (i.e., solar and wind), advanced traditional power (i.e., gas turbine, steam, and combined cycle), and nuclear technologies is the most competitive future strategy to supply 43.7%, 41.6%, and 3.8%, respectively, of Saudi Arabia’s electricity needs by 2050. This paper proposes an optimal strategy for adopting nuclear power. The nuclear capacity of three scenarios was evaluated: a single APR-1400 nuclear reactor, a single SMART-100 nuclear reactor, and a combination of these two reactors. The results of this study indicate that the highest nuclear capacity was achieved by the combination of the APR-1400 and SMART-100 reactors followed by the single APR-1400 reactor and then the single SMART-100 reactor. However, the single G4ECONS nuclear reactor shows a higher capacity than the single APR-1400 reactor in other evaluated scenarios. The combined reactor strategy may be the most feasible option if the capital cost of a first-of-a-kind SMART-100 reactor is reduced by 62.3%. The cost reductions result from including factors like the time required to build the nuclear power plants in the MESSAGE tool calculation. Also, CO2 taxation will increase nuclear power’s feasibility in the Saudi Arabian energy system. However, the share of renewable energy is predicted to be more affected by the taxation of CO2. In this study, the proposed approach can provide more flexible strategic options for countries embarking on nuclear energy. These flexible strategic options can optimize their national energy mix for long-term planning.

ACS Style

Shadwan M. M. Esmail; Jae Hak Cheong. Studies on Optimal Strategy to Adopt Nuclear Power Plants into Saudi Arabian Energy System Using MESSAGE Tool. Science and Technology of Nuclear Installations 2021, 2021, 1 -26.

AMA Style

Shadwan M. M. Esmail, Jae Hak Cheong. Studies on Optimal Strategy to Adopt Nuclear Power Plants into Saudi Arabian Energy System Using MESSAGE Tool. Science and Technology of Nuclear Installations. 2021; 2021 ():1-26.

Chicago/Turabian Style

Shadwan M. M. Esmail; Jae Hak Cheong. 2021. "Studies on Optimal Strategy to Adopt Nuclear Power Plants into Saudi Arabian Energy System Using MESSAGE Tool." Science and Technology of Nuclear Installations 2021, no. : 1-26.

Research article
Published: 16 April 2021 in Science and Technology of Nuclear Installations
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A methodology for segmenting large metal components from nuclear power plants has been developed with a view to minimizing the number of containers to emplace segmented pieces. Spherocylinder-type and rectangular prism-type objects are modeled in shapes, and equations to calculate heights, widths, lengths, or angles for segmentation and the number of pieces are derived using geometric theorems, with a hypothetical ‘virtual rectangle’ being introduced for simplification. Applicability of the new methodology is verified through case studies assuming that each segmented piece is packaged into a 200 L container, and a procedure for adjusting potential overestimation of the segmented pieces due to the virtual rectangle is proposed. The new approach results in fewer segmented pieces but more containers than an existing segmentation study using 3D modeling. It is demonstrated that the number of containers can be further reduced, however, if the generalized methodology is followed by 3D modeling. In addition, it is confirmed that the generalized approach is also applicable to a nonstandard shapes such as ellipsoidal shape but only under limited conditions. Sensitivity analyses are conducted by changing dimensions of the objects and container, which brings about an optimal dimension of container as well. The generalized approach would be utilized either alone in decommissioning planning to estimate waste from segmentation of large metal components or combined with 3D modeling to optimize segmentation operation.

ACS Style

Jae Min Lee; Jae Hak Cheong; Jooho Whang. Methodology for Establishing Segmentation Strategy for Large Metal Components from Nuclear Power Plants with Consideration of Packaging into Containers. Science and Technology of Nuclear Installations 2021, 2021, 1 -19.

AMA Style

Jae Min Lee, Jae Hak Cheong, Jooho Whang. Methodology for Establishing Segmentation Strategy for Large Metal Components from Nuclear Power Plants with Consideration of Packaging into Containers. Science and Technology of Nuclear Installations. 2021; 2021 ():1-19.

Chicago/Turabian Style

Jae Min Lee; Jae Hak Cheong; Jooho Whang. 2021. "Methodology for Establishing Segmentation Strategy for Large Metal Components from Nuclear Power Plants with Consideration of Packaging into Containers." Science and Technology of Nuclear Installations 2021, no. : 1-19.

Journal article
Published: 08 March 2021 in Chemosensors
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Functional plastic scintillators have attracted much attention for their usefulness in on-site monitoring and detection in environments. In this study, we elucidated a highly reliable and functional plastic scintillator for detection of radioactive strontium, which means a potent perovskite-loaded polymeric scintillation material based on epoxy and 2,5-diphenyloxazole (PPO). Moreover, Monte Carlo N-Particle (MCNP) simulation was performed to optimize the thickness of a plastic scintillator for efficient strontium detection. A thickness of 2 mm was found to be the optimum thickness for strontium beta-ray detection. A newly developed plastic scintillator with 430 nm emission from perovskite loading could trigger scintillation enhancement employing potential indication of perovskite energy transfer into a photomultiplier (PMT) detector. Furthermore, the response to beta-ray emitter of 90Sr was compared to commercial scintillator of BC-400 by exhibiting detection efficiency in the energy spectrum with a fabricated perovskite-loaded plastic scintillator. We believe that this suggested functional plastic scintillator could be employed as a radiation detector for strontium detection in a wide range of applications including decommissioning sites in nuclear facilities, nuclear security and monitoring, nonproliferation, and safeguards.

ACS Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection. Chemosensors 2021, 9, 53 .

AMA Style

Hara Kang, Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jae Cheong. Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection. Chemosensors. 2021; 9 (3):53.

Chicago/Turabian Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. 2021. "Preliminary Studies of Perovskite-Loaded Plastic Scintillator Prototypes for Radioactive Strontium Detection." Chemosensors 9, no. 3: 53.

Journal article
Published: 18 November 2020 in Annals of Nuclear Energy
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Based upon relevant statistics, it was suggested that potential scenarios for uncontrolled recycling of disposed activated metal waste, once it is excavated out of a near-surface repository, would not be excluded without prudent deliberation. Recycling a by-product slag from a smelter in parking lot foundation shows the highest radiation dose per unit activity concentration for 94Nb among combinations of twenty-one scenarios and seven radionuclides selected. The variability of calculation results were studied through deterministic sensitivity analyses, and probabilistic analyses were also conducted to understand the probability distribution of the resulting radiological risk. Case studies on activated large metal components dismantled from three nuclear power plants implied that the radiation dose may exceed the reference levels for inadvertent human intrusion. Accordingly, a few options to reduce the likelihood of excavation of activated metal waste in case of human intrusion and to limit its radiological consequence were proposed.

ACS Style

Wang Hyeon Lee; Jae Hak Cheong. Potential radiological hazard and options to cope with consequences from recycling of activated metal waste disposed of at a near-surface disposal facility. Annals of Nuclear Energy 2020, 152, 107993 .

AMA Style

Wang Hyeon Lee, Jae Hak Cheong. Potential radiological hazard and options to cope with consequences from recycling of activated metal waste disposed of at a near-surface disposal facility. Annals of Nuclear Energy. 2020; 152 ():107993.

Chicago/Turabian Style

Wang Hyeon Lee; Jae Hak Cheong. 2020. "Potential radiological hazard and options to cope with consequences from recycling of activated metal waste disposed of at a near-surface disposal facility." Annals of Nuclear Energy 152, no. : 107993.

Review
Published: 28 October 2020 in Chemosensors
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The detection and monitoring systems of low energy beta particles are of important concern in nuclear facilities and decommissioning sites. Generally, low-energy beta-rays have been measured in systems such as liquid scintillation counters and gas proportional counters but time is required for pretreatment and sampling, and ultimately it is difficult to obtain a representation of the observables. The risk of external exposure for low energy beta-ray emitting radioisotopes has not been significantly considered due to the low transmittance of the isotopes, whereas radiation protection against internal exposure is necessary because it can cause radiation hazard to into the body through ingestion and inhalation. In this review, research to produce various types of detectors and to measure low-energy beta-rays by using or manufacturing plastic scintillators such as commercial plastic and optic fiber is discussed. Furthermore, the state-of-the-art beta particle detectors using plastic scintillators and other types of beta-ray counters were elucidated with regard to characteristics of low energy beta-ray emitting radioisotopes. Recent rapid advances in organic matter and nanotechnology have brought attention to scintillators combining plastics and nanomaterials for all types of radiation detection. Herein, we provide an in-depth review on low energy beta emitter measurement.

ACS Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. Low Energy Beta Emitter Measurement: A Review. Chemosensors 2020, 8, 106 .

AMA Style

Hara Kang, Sujung Min, Bumkyung Seo, Changhyun Roh, Sangbum Hong, Jae Cheong. Low Energy Beta Emitter Measurement: A Review. Chemosensors. 2020; 8 (4):106.

Chicago/Turabian Style

Hara Kang; Sujung Min; Bumkyung Seo; Changhyun Roh; Sangbum Hong; Jae Cheong. 2020. "Low Energy Beta Emitter Measurement: A Review." Chemosensors 8, no. 4: 106.

Journal article
Published: 13 October 2020 in Energies
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In order to estimate the radiological characteristics of disused dry storage systems for spent nuclear fuel, a stepwise framework to calculate neutron sources (ORIGEN-ARP), incident neutron flux and reaction rate (MCNPX), effective cross-section (hand calculation), and residual activity (ORIGEN-2) was established. Applicability of the framework was demonstrated by comparing the residual activity of a commercialized storage system, HI-STORM 100, listed in the safety analysis report and calculated in this study. For a reference case assuming an impurity-free storage system, the modified effective cross-sections were theoretically interpreted and the need for managing disused components as a radioactive waste for at least four years was demonstrated. Sensitivity analyses showed that the higher burnup induces the higher residual radioactivity, and the impurity 59Co may extend the minimum decay-in-storage period up to 51 years within the reported range of 59Co content in stainless steel. The extended long-term storage over 100 years, however, caused no significant increase in residual radioactivity. Impurity control together with appropriate decay-in-storage was proposed as an effective approach to minimize the secondary radioactive waste arising from disused dry storage systems. The results of this study could be used to optimize the decommissioning and waste management plan regarding interim storage of spent fuel.

ACS Style

Se Geun Lee; Jae Hak Cheong. Neutron Activation of Structural Materials of a Dry Storage System for Spent Nuclear Fuel and Implications for Radioactive Waste Management. Energies 2020, 13, 5325 .

AMA Style

Se Geun Lee, Jae Hak Cheong. Neutron Activation of Structural Materials of a Dry Storage System for Spent Nuclear Fuel and Implications for Radioactive Waste Management. Energies. 2020; 13 (20):5325.

Chicago/Turabian Style

Se Geun Lee; Jae Hak Cheong. 2020. "Neutron Activation of Structural Materials of a Dry Storage System for Spent Nuclear Fuel and Implications for Radioactive Waste Management." Energies 13, no. 20: 5325.

Journal article
Published: 24 June 2020 in Sustainability
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Although the generation of large components from nuclear power plants is expected to gradually increase in the future, comprehensive studies on the radiological risks of the predisposal management of large components have been rarely reported in open literature. With a view to generalizing the assessment framework for the radiological risks of the processing and transport of a representative large component—a steam generator—12 scenarios were modeled in this study based on past experiences and practices. In addition, the general pathway dose factors normalized to the unit activity concentration of radionuclides for processing and transportation were derived. Using the general pathway dose factors, as derived using the approach established in this study, a specific assessment was conducted for steam generators from a pressurized water reactor (PWR) or a pressurized heavy water reactor (PHWR) in Korea. In order to demonstrate the applicability of the developed approach, radiation doses reported from actual experiences and studies are compared to the calculated values in this study. The applicability of special arrangement transportation of steam generators assumed in this study is evaluated in accordance with international guidance. The generalized approach to assessing the radiation doses can be used to support optimizing the predisposal management of large components in terms of radiological risk.

ACS Style

Ga Hyun Chun; Jin-Ho Park; Jae Hak Cheong. Calculation of Potential Radiation Doses Associated with Predisposal Management of Dismantled Steam Generators from Nuclear Power Plants. Sustainability 2020, 12, 5149 .

AMA Style

Ga Hyun Chun, Jin-Ho Park, Jae Hak Cheong. Calculation of Potential Radiation Doses Associated with Predisposal Management of Dismantled Steam Generators from Nuclear Power Plants. Sustainability. 2020; 12 (12):5149.

Chicago/Turabian Style

Ga Hyun Chun; Jin-Ho Park; Jae Hak Cheong. 2020. "Calculation of Potential Radiation Doses Associated with Predisposal Management of Dismantled Steam Generators from Nuclear Power Plants." Sustainability 12, no. 12: 5149.

Journal article
Published: 12 May 2020 in Energies
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In order to expand our understanding of the characteristics of radioactive effluent from nuclear power plants under decommissioning, which have not been systematically investigated, a series of source term models of radioactive effluent after permanent shutdown has been established based upon theoretical reasoning on the design and operation features of plants and derived in terms of fifteen arguments. Comprehensive radioactive effluent data have been collected and profiled from twenty-eight decommissioning pressurized water reactors, and annual trends of effluent from each plant have been quantitatively analyzed using Mann-Kendall statistical test. In addition, the characteristics of collected effluent data have been qualitatively interpreted based upon arguments newly proposed in this study. Furthermore, potential decreasing of dilution factor for liquid effluent and its safety implications are identified. The source term models and verified characteristics of radioactive effluent after permanent shutdown developed in this study can be used for establishing more efficient discharge monitoring program for decommissioning authorization.

ACS Style

Ji Su Kang; Jae Hak Cheong. Characteristics of Radioactive Effluent Releases from Pressurized Water Reactors after Permanent Shutdown. Energies 2020, 13, 2436 .

AMA Style

Ji Su Kang, Jae Hak Cheong. Characteristics of Radioactive Effluent Releases from Pressurized Water Reactors after Permanent Shutdown. Energies. 2020; 13 (10):2436.

Chicago/Turabian Style

Ji Su Kang; Jae Hak Cheong. 2020. "Characteristics of Radioactive Effluent Releases from Pressurized Water Reactors after Permanent Shutdown." Energies 13, no. 10: 2436.

Journal article
Published: 24 April 2019 in Nuclear Engineering and Technology
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A standard form of six stylized human intrusion scenarios for a near-surface disposal facility (e.g. the planned Korean repository, Gyeongju Phase II) is proposed through re-categorization of totally thirty-one past cases reported in public literature. A reference assessment framework for inadvertent human intrusion is newly developed using GENII Version 2 conforming to the ICRP Publication 60 and thereafter. Calculated dose from the assessment framework is verified by comparing with hand calculation results for simplified model equations independently derived. Results from GENII Version 2 and 1.485 show inevitable differences, which is mainly attributed to the difference in the external dose assessment model. If intake dose coefficients in GENII Version 1.485 are modified, the difference can be reduced but still exist to an extent. Through deterministic and probabilistic sensitivity analysis, most affecting four parameters are derived and uncertainties of the parameters are quantified. It is expected that the reference assessment framework together with representative stylized scenarios can be used to do a human intrusion impact assessment for a specific repository using site-specific information. Especially, the past practice of human intrusion impact assessment using GENII Version 1.485 with or without modification may be replaced with the new assessment framework developed in this study.

ACS Style

Ki Nam Kwon; Jae Hak Cheong. Development of a reference framework to assess stylized human intrusion scenarios using GENII Version 2 considering design features of planned near-surface disposal facility in Korea. Nuclear Engineering and Technology 2019, 51, 1561 -1574.

AMA Style

Ki Nam Kwon, Jae Hak Cheong. Development of a reference framework to assess stylized human intrusion scenarios using GENII Version 2 considering design features of planned near-surface disposal facility in Korea. Nuclear Engineering and Technology. 2019; 51 (6):1561-1574.

Chicago/Turabian Style

Ki Nam Kwon; Jae Hak Cheong. 2019. "Development of a reference framework to assess stylized human intrusion scenarios using GENII Version 2 considering design features of planned near-surface disposal facility in Korea." Nuclear Engineering and Technology 51, no. 6: 1561-1574.

Journal article
Published: 31 December 2018 in Journal of the Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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ACS Style

Kun-Su Lim; Jae Hak Cheong; Joo Ho Whang. Screening Assessment of Radiological Effect From Clearance of Decommissioning Concrete Waste Based Upon Recycling Framework of Construction Waste in Korea. Journal of the Nuclear Fuel Cycle and Waste Technology(JNFCWT) 2018, 16, 441 -454.

AMA Style

Kun-Su Lim, Jae Hak Cheong, Joo Ho Whang. Screening Assessment of Radiological Effect From Clearance of Decommissioning Concrete Waste Based Upon Recycling Framework of Construction Waste in Korea. Journal of the Nuclear Fuel Cycle and Waste Technology(JNFCWT). 2018; 16 (4):441-454.

Chicago/Turabian Style

Kun-Su Lim; Jae Hak Cheong; Joo Ho Whang. 2018. "Screening Assessment of Radiological Effect From Clearance of Decommissioning Concrete Waste Based Upon Recycling Framework of Construction Waste in Korea." Journal of the Nuclear Fuel Cycle and Waste Technology(JNFCWT) 16, no. 4: 441-454.

Article
Published: 26 September 2018 in Journal of Nuclear Science and Technology
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In order to develop a methodology to guarantee the conformance to operational discharge limits for liquid effluent from a NPP at an early stage of design, a risk-informed approach was proposed and its applicability was verified for APR 1400. Existing methodology to calculate risk-based detection limit for a single radionuclide was improved by incorporating a new model to derive more realistic pathway dose factors. A new simple expression was also proposed to adjust risk-based detection limits for multiple radionuclides mixture if necessary. In addition, a new procedure to warrant the compliance with discharge limits by controlling detection limits of only a few principal radionuclides was established in accordance with risk-informed concept. Through case studies for APR 1400 to be commissioned at a hypothetical site, it was shown that calculated pathway dose factors are more realistic for majority of radionuclides. It also turns out that neither present detection limits nor unadjusted risk-based detection limits can be justified when the radionuclide composition is unknown, however further adjustment of detection limits or increasing additional dilution factor resolves the problem. Finally, ten principal radionuclides were identified and shown to be enough for liquid effluent control at APR 1400 from a risk-informed point of view.

ACS Style

Na Yoon Choi; Jae Hak Cheong. A priori risk-informed approach to ensure the compliance with discharge limits for liquid radioactive effluent to be discharged from APR 1400. Journal of Nuclear Science and Technology 2018, 56, 41 -54.

AMA Style

Na Yoon Choi, Jae Hak Cheong. A priori risk-informed approach to ensure the compliance with discharge limits for liquid radioactive effluent to be discharged from APR 1400. Journal of Nuclear Science and Technology. 2018; 56 (1):41-54.

Chicago/Turabian Style

Na Yoon Choi; Jae Hak Cheong. 2018. "A priori risk-informed approach to ensure the compliance with discharge limits for liquid radioactive effluent to be discharged from APR 1400." Journal of Nuclear Science and Technology 56, no. 1: 41-54.

Research article
Published: 31 October 2017 in Science and Technology of Nuclear Installations
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With a view to providing supportive information for the decision-making on the direction of the future nuclear energy systems in Korea (i.e., direct disposal or recycling of spent nuclear fuel) to be made around 2020, quantitative studies on the spent nuclear fuel (SNF) including transuranic elements (TRUs) and a series of economic analyses were conducted. At first, the total isotopic inventory of TRUs in the SNF to be generated from all thirty-six units of nuclear power plants in operation or under planning is estimated based on the Korean government’s official plan for nuclear power development. Secondly, the optimized deployment strategies are proposed considering the minimum number of sodium cooled-fast reactors (SFRs) needed to transmute all TRUs. Finally, direct disposal and Pyro-SFR closed nuclear energy systems were compared using equilibrium economic model and considering reduction of TRUs and electricity generation as benefits. Probabilistic economic analysis shows that the assumed total generation cost for direct disposal and Pyro-SFR closed nuclear energy systems resides within the range of 13.60~33.94 mills/kWh and 11.40~25.91 mills/kWh, respectively. Dominant cost elements and the range of SFR overnight cost which guarantees the economic feasibility of the Pyro-SFR closed nuclear energy system over the direct disposal option were also identified through sensitivity analysis and break-even cost estimation.

ACS Style

Muhammad Minhaj Khan; Jae Min Lee; Jae Hak Cheong; Joo Ho Whang. Feasibility Studies on Pyro-SFR Closed Fuel Cycle and Direct Disposal of Spent Nuclear Fuel in Line with the Latest National Policy and Strategy of Korea. Science and Technology of Nuclear Installations 2017, 2017, 1 -17.

AMA Style

Muhammad Minhaj Khan, Jae Min Lee, Jae Hak Cheong, Joo Ho Whang. Feasibility Studies on Pyro-SFR Closed Fuel Cycle and Direct Disposal of Spent Nuclear Fuel in Line with the Latest National Policy and Strategy of Korea. Science and Technology of Nuclear Installations. 2017; 2017 ():1-17.

Chicago/Turabian Style

Muhammad Minhaj Khan; Jae Min Lee; Jae Hak Cheong; Joo Ho Whang. 2017. "Feasibility Studies on Pyro-SFR Closed Fuel Cycle and Direct Disposal of Spent Nuclear Fuel in Line with the Latest National Policy and Strategy of Korea." Science and Technology of Nuclear Installations 2017, no. : 1-17.

Article
Published: 25 May 2017 in Journal of Nuclear Science and Technology
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In order to review if present detection limits of radionuclides in liquid effluent from nuclear power plants are effective enough to warrant compliance with regulatory discharge limits, a risk-based approach is developed to derive a new detection limit for each radionuclide based on radiological criteria. Equations and adjustment factors are also proposed to discriminate the validity of the detection limits for multiple radionuclides in the liquid effluent with or without consideration of the nuclide composition. From case studies to three nuclear power plants in Korea with actual operation data from 2006 to 2015, the present detection limits have turned out to be effective for Hanul Unit 1 but may not be sensitive enough for Kori Unit 1 (8 out of 14 radionuclides) and Wolsong Unit 1 (9 out of 42 radionuclides). However, it is shown that the present detection limits for the latter two nuclear power plants can be justified, if credit is given to the radionuclide composition. Otherwise, consideration should be given to adjustment of the present detection limits. The risk-based approach of this study can be used to determine the validity of established detection limits of a specific nuclear power plant.

ACS Style

Jae Hak Cheong. Calculation of risk-based detection limits for radionuclides in the liquid effluents from Korean nuclear power plants. Journal of Nuclear Science and Technology 2017, 54, 957 -968.

AMA Style

Jae Hak Cheong. Calculation of risk-based detection limits for radionuclides in the liquid effluents from Korean nuclear power plants. Journal of Nuclear Science and Technology. 2017; 54 (9):957-968.

Chicago/Turabian Style

Jae Hak Cheong. 2017. "Calculation of risk-based detection limits for radionuclides in the liquid effluents from Korean nuclear power plants." Journal of Nuclear Science and Technology 54, no. 9: 957-968.

Original articles
Published: 01 April 1996 in Separation Science and Technology
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A mathematical model was developed to investigate the characteristics of Co2+ removal by the pre-formed ferrite process. In this study, surface adsorption, hydrolysis-precipitation, and ion exchange were considered as Co2+ removal mechanisms, and incorporated into the model. In addition, a series of batch experiments was performed to remove Co2+ ions from aqueous solution, and the removal characteristics of Co2+ were analyzed by considering equilibrium pH, shaking time, ionic strength, and the effect of EDTA and Ca2+ as a chelating agent and a competing cation, respectively. Finally, the model proposed in this study was applied to the given experimental system, and it turned out that the pH-edge could be successfully predicted by the model. The experimental results were well-fitted by a Freundlich isotherm, and the standard enthalpy change of the reaction was 25.02 kJ·mol−1. The removal efficiency was slightly diminished by increasing the ionic strength and the initial concentration of Co2+; however, the effect of the competing cation, Ca2+, was negligible.

ACS Style

Jae Hak Cheong; Kun Jai Lee. Removal of Co2+Ions from Aqueous Solution by Ferrite Process. Separation Science and Technology 1996, 31, 1137 -1160.

AMA Style

Jae Hak Cheong, Kun Jai Lee. Removal of Co2+Ions from Aqueous Solution by Ferrite Process. Separation Science and Technology. 1996; 31 (8):1137-1160.

Chicago/Turabian Style

Jae Hak Cheong; Kun Jai Lee. 1996. "Removal of Co2+Ions from Aqueous Solution by Ferrite Process." Separation Science and Technology 31, no. 8: 1137-1160.