• Title/Summary/Keyword: Exposure scenarios

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Preliminary Radiation Exposure Dose Evaluation for Workers of the Landfill Disposal Facility Considering the Radiological Characteristics of Very Low Level Concrete and Metal Decommissioning Wastes (극저준위 콘크리트, 금속 해체방폐물의 방사선적 특성을 고려한 매립형 처분시설 방사선작업자 예비 피폭선량 평가)

  • Ho-Seog Dho;Ye-Seul Cho;Hyun-Goo Kang;Jae-Chul Ha
    • Journal of Radiation Industry
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    • v.17 no.4
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    • pp.509-518
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    • 2023
  • The Kori Unit 1 nuclear power plant, which is planned to be dismantled after permanent shutdown, is expected to generate a large amount of various types of radioactive waste during the dismantling process. For the disposal of Very-low-level waste, which is expected to account for the largest amount of generation, the Korea Radioactive waste Agency (KORAD) is in the process of detailed design to build a 3-phase landfill disposal facility in Gyeongju. In addition, a large container is being developed to efficiently dispose of metal and concrete waste, which are mainly generated as Very low-level waste of decommissioning. In this study, based on the design characteristics of the 3-phase landfill disposal facility and the large container under development, radiation exposure dose evaluation was performed considering the normal and accident scenarios of radiation workers during operation. The direct exposure dose evaluation of workers during normal operation was performed using the MCNP computer program, and the internal and external exposure dose evaluation due to damage to the decommissioning waste package during a drop accident was performed based on the evaluation method of ICRP. For the assumed scenario, the exposure dose of worker was calculated to determine whether the exposure dose standards in the domestic nuclear safety act were satisfied. As a result of the evaluation, it was confirmed that the result was quite low, and the result that satisfied the standard limit was confirmed, and the radiational disposal suitability for the 3-phase landfill disposal facility of the large container for dismantled radioactive waste, which is currently under development, was confirmed.

Preliminary Evaluation of Clearance Level of Uranium in Metal Waste Using the RESRAD-RECYCLE Code (RESRAD-RECYCLE 전산코드를 활용한 금속폐기물 내 우라늄 자체처분 허용농도 예비 평가)

  • SunWoo Lee;JungHwan Hong;JungSuk Park;KwangPyo Kim
    • Journal of Radiation Industry
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    • v.17 no.4
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    • pp.457-469
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    • 2023
  • The clearance level by nuclide is announced by the Nuclear Safety and Security Commission. However, the clearance level of uranium existing in nature has not been announced, and research is needed. Therefore, the purpose of this study was to evaluate the clearance level of uranium nuclides appropriate to domestic conditions preliminary. For this purpose, this study selected major processes for recycling metal wastes and analyzed the exposure scenarios and major input factors by investigating the characteristics of each process. Then, the radiation dose to the general public and workers was evaluated according to the selected scenarios. Finally, the results of the radiation dose per unit radioactivity for each scenario were analyzed to derive the clearance level of uranium in metal waste. The results of the radiation dose assessment for both the general public and workers per unit radioactivity of uranium isotopes were shown to meet the allowable dose (individual dose of 10 µSv y-1 and collective dose of 1 Man-Sv y-1) regulated by the Nuclear Safety and Security Commission. The most conservative scenarios for volumetric and surface contamination were evaluated for the handling of the slag generated after the melting of the metal waste and the direct reuse of the contaminated metal waste into the building without further disposal. For each of these scenarios, the radioactivity concentration by uranium isotope was calculated, and the clearance level of uranium in metal waste was calculated through the radioactivity ratio by enrichment. The results of this study can be used as a basic data for defining the clearance level of uranium-contaminated radioactive waste.

Evaluation of radiological safety according to accident scenarios for commercialization of spent resin mixture treatment device

  • Choi, Woo Nyun;Byun, Jaehoon;Kim, Hee Reyoung
    • Nuclear Engineering and Technology
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    • v.54 no.7
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    • pp.2606-2613
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    • 2022
  • Spent resin often exceeds radiation limits for safe disposal, creating a need for commercial-scale treatment techniques to reduce resin radioactivity. In this study, the radiological safety of a commercialized spent resin treatment device with a treatment capacity of 1 ton/day was evaluated. The results confirm that the device is radiologically safe in the event of an accident. This device desorbs 14C from the spent resin, allowing disposal as low-level waste instead of intermediate-level waste. The device also reduces overall waste by recycling the extracted 14C. Potential accident scenarios were explored to enable dose assessments for both internal and external exposure while preventing further spillage of the device and processing the spilled resin. The scenarios involved the development of a surface fracture on the resin mixture separator and microwave systems, which were operated under pressure and temperature of 0-6 bar and 0-150 ℃, respectively. In the case of accidents with separator and microwave device, the maximum allowable working time of worker were derived, respectively, considering external and internal exposures. When wearing the respirator corresponding to APF 50, in the case of the microwave device accident scenario, the radiological safety was confirmed when the maximum worker worked within 132.1 h.

Estimation of Manganese Levels in Cord Blood of Pregnant Workers (임신 여성 근로자의 제대혈 중 망간 농도 추정)

  • Lee, Aram;Choi, Kyungho;Kim, Hai-Joong;Lee, Jeong Jae;Choi, Gyuyeon;Kim, Sungjoo;Kim, Su Young;Cho, Geumjoon;Kim, Youg Don;Suh, Eunsook;Kim, Sung Koo;Eun, So-Hee;Eom, Soyong;Kum, Seunghyo;Kim, Gun-Ha;Moon, Hyo-Bang;Kim, Sungkyoon;Choi, Sooran;Park, Jeongim
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.28 no.3
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    • pp.292-303
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    • 2018
  • Objectives: This study aims to analyze manganese (Mn) concentrations in maternal and cord bloods at delivery and to estimate the Mn exposure risk for fetuses whose mothers were occupationally exposed to Mn. Materials and Methods: Forty-six pairs of maternal and cord blood samples were collected at delivery from mothers who were occupationally unexposed to Mn. Mn concentrations of blood were analyzed by graphite furnace atomic absorption spectrometer. Mn exposure levels for fetuses of female workers were estimated by simulating two working exposure scenarios. Results: The geometric mean concentration of Mn in maternal and cord blood were $27.0(1.34){\mu}g/L$, $46.6(1.25){\mu}g/L$, respectively. Transfer ratios of Mn from maternal to cord blood were $1.81{\pm}0.62$, which indicated that the Mn concentrations in cord blood were higher than those in maternal blood. Mn concentrations in cord blood for the worse or general scenarios were estimated to $22.3-1,881{\mu}g/L$ and $1.59-308{\mu}g/L$, respectively. The probabilities of exceeding $74{\mu}g/L$, which was adopted as a reference level reported in a previous study, were 95% and 44% for the two scenarios, respectively. Conclusions: Comparable levels of Mn exposure in maternal or cord blood to those in this study have shown various health effects in previous studies. This suggests that Mn exposure levels in mothers and fetuese in Korea need to be monitored and managed. In addition, female workers who are occupationally exposed to Mn should be protected from the exposure since their fetuses can be exposed to Mn at risky levels during their pregnancy.

The training system based on virtual environments to protect workers and to prevent incidents and accidents during decommissioning of nuclear facilities (원자력시설 해체 작업자 보호 및 사고 예방을 위한 가상현실 기반의 훈련 시스템)

  • Jeong, KwanSeong;Moon, Jei-Kwon;Choi, Byung-Seon;Yoon, TaeMan
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2015.11a
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    • pp.294-297
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    • 2015
  • Decommissioning of nuclear facilities should be accomplished by assuring the safety of workers because decommissioning activities of nuclear facilities are under high radioactivity and work difficulty. It is necessary that before decommissioning, the radiation exposure dose of workers has to be evaluated and assessed under the principle of ALARA (as low as reasonably achievable). Furthermore, to improve the proficiency of decommissioning environments, method and system need to be developed. The legacy methods of exposure dose measurement and assessment had the limitations to modify and simulate the exposure dose to workers prior to practical activities because those should be accomplished without changes of working routes under predetermined scenarios. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. It can be concluded that this system is able to protect from accidents and enable workers to improve his familiarization about working environments. It is expected that this system can reduce human errors because workers are able to improve the proficiency of hazardous working environments due to virtual training like real decommissioning situations. In the end, the safety during decommissioning of nuclear facilities will be guaranteed under the principle of ALARA.

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Organ dose reconstruction for the radiation epidemiological study of Korean radiation workers: The first dose evaluation for the Korean Radiation Worker Study (KRWS)

  • Tae-Eun Kwon;Areum Jeong;Wi-Ho Ha;Dalnim Lee;Songwon Seo;Junik Cho;Euidam Kim;Yoonsun Chung;Sunhoo Park
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.725-733
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    • 2023
  • The Korea Institute of Radiological and Medical Sciences has started a radiation epidemiological study, titled "Korean Radiation Worker Study," to evaluate the health effects of occupational exposure to radiation. As a part of this study, we investigated the methodologies and results of reconstructing organ-specific absorbed doses based on personal dose equivalent, Hp(10), reported from 1984 to 2019 for 20,605 Korean radiation workers. For the organ dose reconstruction, representative exposure scenarios (i.e., radiation energy and exposure geometry) were first determined according to occupational groups, and dose coefficients for converting Hp(10) to organ absorbed doses were then appropriately taken based on the exposure scenarios. Individual annual doses and individual cumulative doses were reconstructed for 27 organs, and the highest values were observed in the thyroid doses (on average 0.77 mGy/y and 10.47 mGy, respectively). Mean values of individual cumulative absorbed doses for the red bone marrow, colon, and lungs were 7.83, 8.78, and 8.43 mSv, respectively. Most of the organ doses were maximum for industrial radiographers, followed by nuclear power plant workers, medical workers, and other facility workers. The organ dose database established in this study will be utilized for organ-specific risk estimation in the Korean Radiation Worker Study.

Comparative Study of Exposure Assessment of Dust in Building Materials Enterprises Using ART and Monte Carlo

  • Wei Jiang;Zonghao Wu;Mengqi Zhang;Haoguang Zhang
    • Safety and Health at Work
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    • v.15 no.1
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    • pp.33-41
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    • 2024
  • Background: Dust generated during the processing of building materials enterprises can pose a serious health risk. The study aimed to compare and analyze the results of ART and the Monte Carlo model for the dust exposure assessment in building materials enterprises, to derive the application scope of the two models. Methods: First, ART and the Monte Carlo model were used to assess the exposure to dust in each of the 15 building materials enterprises. Then, a comparative analysis of the exposure assessment results was conducted. Finally, the model factors were analyzed using correlation analysis and the scope of application of the models was determined. Results: The results show that ART is mainly influenced by four factors, namely, localized controls, segregation, dispersion, surface contamination, and fugitive emissions, and applies to scenarios where the workplace information of the building materials enterprises is specific and the average dust concentration is greater than or equal to 1.5 mg/m3. The Monte Carlo model is mainly influenced by the dust concentration in the workplace of building materials enterprises and is suitable for scenarios where the dust concentration in the workplace of the building materials enterprises is relatively uniform and the average dust concentration is less than or equal to 6mg/m3. Conclusion: ART is most accurate when workplace information is specific and average dust concentration is > 1.5 mg/m3; whereas, The Monte Carlo model is the best when dust concentration is homogeneous and average dust concentration is < 6 mg/m3.

Hydrological drought risk assessment for climate change adaptation in South Korea (기후변화 적응을 위한 우리나라 수문학적 가뭄 위험도 평가)

  • Seo, Jungho;Chi, Haewon;Kim, Heey Jin;Kim, Yeonjoo
    • Journal of Korea Water Resources Association
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    • v.55 no.6
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    • pp.421-435
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    • 2022
  • As natural disasters have been increasing due to climate change, sustainable solutions are in need to alleviate the degree of drought hazard, assess and project the drought influence based on future climate change scenarios. In assessing drought risk, socio-economic factors of the region must be considered along with meteorological factors. This study categorized drought hazard, exposure, and vulnerability as three major components of drought risk according to the Intergovernmental panel on Climate Change (IPCC) risk assessment framework, and selected indices for each component to quantify the drought risk in South Korea according to the mid-size basins. Combinations of climate scenarios (Representative Concentration Pathway; RCP 2.6 and RCP 8.5) and socio-economic scenarios (Shared Socio-economic Pathways; SSP 1, SSP2 and SSP3) for the near future (2030-2050) ant the far future (2080-2099) were utilized in drought risk analysis, and results were compared with the historical data (1986-2005). In general, the drought risks for all scenarios shows large increases as time proceeds to the far furture. In addition, we analyzed the rank of drought hazard, exposure, vulnerability for drought risk, and each of their contribution. The results showed that the drought hazard is the most contributing component to the increase of drought risk in future and each basin shows varying contributing components. Finally, we suggested countermeasures for each basin according to future climate change scenarios, and thus this study provides made the basis for establishing drought management measures.

Risk Assessment of Indoor Pollution by BTEX Released from Groundwater (지하수내 BTEX에 의한 실내오염시 위해도 평가)

  • 유동한;이한수;김상준;양지원
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.5
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    • pp.373-381
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    • 2002
  • Benzene, Ethyl-benzene, Toluene and Xylene (BTEX) can be released to a groundwater in case of the oil leakage from underground storage tank of a gas station. These chemicals are found to contribute to the total inhalation risk from contaminated indoor air. This study presents the assessment of a human exposure to such chemicals released from the groundwater into indoor air. At first, a 2-compartment model is developed to describe the transfer and distribution of the chemicals released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such BTEX for adults based on two sets of exposure scenarios. Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor pollution by BTEX released from contaminated groundwater.

Assessment of Human Exposures to Indoor Radon Released from Groundwater (지하수로부터의 실내 라돈오염시 인체노출평가)

  • 유동한;김상준;양지원
    • Journal of Korean Society for Atmospheric Environment
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    • v.17 no.3
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    • pp.241-249
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    • 2001
  • A report by the National Research Council in the United States suggested that many lung cancer deaths each year are associated with breathing radon in indoor air. Most of the indoor radon comes directly from soil beneath the basement of foundation. Recently, radon released from groundwater is found to contribute to the total inhalation risk from indoor air. This study presents the assessment of a exposure to radon released from the groundwater into indoor air. At first, a 3-compartment model is describe the transfer and distribution if radon released from groundwater in a house through showering, washing clothes, and flushing toilets. The model is used to estimate a daily human exposure through inhalation of such radon for adults based on two sets of exposure scenarios, Finally, a sensitivity analysis is used to identify important parameters. The results obtained from the study would help to increase the understanding of risk assessment issues associated with the indoor radon released from groundwater.

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