• Title/Summary/Keyword: Radioactive dose

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Comparison of Environmental Radiation Survey Analysis Results in a High Dose Rate Environment Using CZT, NaI(Tl), and LaBr3(Ce) Detectors

  • Sungyeop Joung;Wanook Ji;Eunjung Lee;Young-Yong Ji;Yoomi Choi
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.21 no.4
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    • pp.543-558
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    • 2023
  • Currently, Japan is undertaking a nationwide project to measure and map radioactive contamination around Fukushima, as part of the efforts to restore normalcy following the nuclear accident. The Japan Atomic Energy Agency (JAEA) manages the Fukushima Environmental Safety Center, located approximately 20 km north of the Fukushima Daiichi nuclear power plant in Minamisōma City, Fukushima Prefecture. In collaboration with the JAEA, this study involved conducting comparison experiments and analyses with radiation detectors in high radiation environments, a challenging task in Korean environments. Environmental radiation surveys were conducted using three types of detectors: CZT, NaI(Tl), and LaBr3(Ce), across two contaminated areas. Dose rate values were converted using dose rate conversion factors for each detector type, and dose rate maps were subsequently created and compared. The detectors yielded similar results, demonstrating their feasibility and reliability in high radiation environments. The findings of this study are expected to be a crucial reference for enhancing the verification and supplementation of procedures and methods in future radiation measurements and mobile surveys in high-radiation environments, using these three types of radiation instruments.

Evaluation of exposure to ionizing radiation of medical staff performing procedures with glucose labeled with radioactive fluorine - 18F-FDG

  • Michal Biegala;Marcin Brodecki;Teresa Jakubowska;Joanna Domienik-Andrzejewska
    • Nuclear Engineering and Technology
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    • v.56 no.1
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    • pp.335-339
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    • 2024
  • Employees of nuclear medicine facilities performing medical procedures with the use of open radioactive sources require continuous detailed control of exposure to ionizing radiation. Thermoluminescent (TL) detectors placed in dosimeters: for the whole body, for lenses, ring and wrist dosimeters were used to assess exposure. The highest whole-body exposure of (1.70 ± 1.09) µSv/GBq was recorded in nurses administering radiopharmaceutical to patients. The highest exposure to lenses and fingers was recorded for employees of the quality control zone and it was (8.08 ± 2.84) µSv/GBq and a maximum of (1261.46 ± 338.93) µSv/GBq, respectively. Workers in the production zone received the highest doses on their hands, i.e. (175.67 ± 13.25) µSv/GBq. The measurements performed showed that the analyzed workers may be classified as exposure category A. Wrist dosimeters are not recommended for use in isotope laboratories due to underestimation of ionizing radiation doses. Appropriately selected shields, which significantly reduce the dose received by employees, must be used in isotope laboratories. Periodic measurements confirmed that the appropriate optimization of exposure reduces the radiation doses received by employees.

Safety Assessment for the Landfill Disposal of Decommissioning Waste Solidified by Magnesium Potassium Phosphate Cement

  • Jeong, Jongtae;Baik, Min-Hoon;Lee, Jae-Kwang;Pyo, Jae-Young;Um, Wooyong;Heo, Jong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.1
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    • pp.13-22
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    • 2022
  • The decommissioning of a nuclear power plant generates large amounts of radioactive waste, which is of several types. Radioactive concrete powder is classified as low-level waste, which can be disposed of in a landfill. However, its safe disposal in a landfill requires that it be immobilized by solidification using cement. Herein, a safety assessment on the disposal of solidified radioactive concrete powder waste in a conceptual landfill site is performed using RESRAD. Furthermore, sensitivity analyses of certain selected input parameters are conducted to investigate their impact on exposure doses. The exposure doses are estimated, and the relative impact of each pathway on them during the disposal of this waste is assessed. The results of this study can be used to obtain information for designing a landfill site for the safe disposal of low-level radioactive waste generated from the decommissioning of a nuclear power plant.

Radiological Impact Assessment for the Domestic On-road Transportation of Radioactive Isotope Wastes (방사성동위원소 폐기물의 국내육상운반에 관한 방사선영향 평가)

  • Seo, Myunghwan;Hong, Sung-Wook;Park, Jin Beak
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.14 no.3
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    • pp.279-287
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    • 2016
  • Korea Radioactive Waste Agency (KORAD) began to operate the low and intermediate level radioactive waste disposal facility in Gyeongju and to transport the radioactive waste containing radioactive isotopes from Daejeon to the disposal facility for the first time at 2015. For this radioactive waste transportation, in this study, radiological impact assessment is carried out for workers and public. The dose rate to workers and public during the transportation is estimated with consideration of the transportation scenarios and is compared with the Korean regulatory limit. The sensitivity analysis is carried out by considering both the variation of release ratios of the radioactive isotopes from the waste and the variation of the distances between the radioactive waste drum and worker during loading and unloading of radioactive waste. As for all the transportation scenarios, radiological impacts for workers and public have met the regulatory limits.

Indoor Radon Levels and Effective Dose Estimation in Learning and Common Living Space of University (대학 내 학습공간과 공동 생활공간에 대한 실내 라돈 농도 측정과 유효선량 산출)

  • Kim, Jung-Su
    • Journal of the Korean Society of Radiology
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    • v.12 no.3
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    • pp.329-334
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    • 2018
  • Radon which is natural component of air is a colorless and odorless radioactive gas. Radon exposure can also occur from some building materials if they are made from radon-containing substances by breathing. In this study, The radiation dose of radon concentration was detected at 8 buildings of the A university during 3-month from June. 2017 to August. 2017. We detected indoor radon exposure at 8 building of the university and estimated annual effective dose. The radon concentration of Hall G and Hall F of the A university represented 81 and $14Bq/m^3$ respectively and average indoor radon concentration represented $41.63Bq/m^3$. Average effective dose was estimated 0.40 mSv/y, maximum effective dose was 0.78 mSv/y and minimum effective dose was 0.13 mSv/y respectively. University is the place that students spend the almost whole time. We suggest ventilation and appropriate management of a building, which could reduce the natural radiation exposure by radon concentration.

Assessment of Absorbed Dose of by Organ according to Thyroidal Uptake of Radioactive Iodine for Adult Korean Males (한국성인 남성을 대상으로 한 방사성옥소의 갑상선 섭취율에 따른 각 장기별 흡수선량 평가)

  • Kim, Junghoon;Lim, Changseon;Whang, Jooho
    • Progress in Medical Physics
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    • v.18 no.4
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    • pp.187-193
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    • 2007
  • In an effort to assess the internal absorbed dose of radionuclides that is suitable to Koreans' physiological characteristics, we asked 28 male Koreans to take $^{131}|$ orally, determined the thyroidal uptake and daily urination ratio, and assessed the absorbed dose by organ. As a result, first, 24 hours after administering, the average thyroidal uptake and the daily urination ratio registered 19.70% and 71.12%, respectively. Second, the whole body effective dose according to the thyroidal uptake calculated herein and the existing ICRP-suggested thyroidal uptake of 30% offered 1.464E-08 Sv and 2.189E-08 Sv, respectively, showing a 1.5 times difference. To evaluate the quantity of the absorbed dose of radioactive iodine, we can better reduce the error in assessing the body exposure dose by conducting measurement according to human races rather than depending on the existing ICRP data.

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Graves' Disease Patients with Large Goiters Respond Best to Radioactive Iodine Doses of at Least 15 mCi: a Sonographic Volumetric Study

  • Jeong, Yun Ah;Yoon, Jee Hee;Kim, Hee Kyung;Kang, Ho-Cheol
    • International journal of thyroidology
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    • v.11 no.2
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    • pp.137-142
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    • 2018
  • Background and Objectives: Radioactive iodine therapy (RAI) is an important treatment modality of Graves' disease (GD), but there is still not a consensus on the optimal dosage regimen. We studied the treatment success rate of different RAI doses, and examined which clinical markers were useful for determining the optimal RAI dosage for successful therapy in Korean patients. Materials and Methods: We retrospectively studied 123 patients with GD treated with RAI between 2004 and 2014 at Chonnam National University Hwasun Hospital. The responder group was defined as patients who developed hypothyroidism requiring levothyroxine replacement following RAI, regardless of the RAI dosage. Results: A total of 54 patients (43.9%) became hypothyroid after the first dose, and 31 needed two to four additional doses to achieve hypothyroidism. In the responder group as a whole (85 patients), the mean total dose of RAI was $15.5{\pm}7.0mCi$ and the mean thyroid volume (TV) was $35.4{\pm}23.4mL$. When divided into low dose (<15 mCi, n=46) and high dose (${\geq}15mCi$, n=39) responder groups, TV was significantly lower in the low-dose responder group ($25.7{\pm}11.4$ vs. $48.4{\pm}31.3$, p<0.001). The optimal cut-off TV for the low-dose responder group was <32.37 mL (sensitivity 80.9%, specificity 76.7%). Conclusion: TV had significant effects on the outcome of RAI in GD patients. The optimal fixed RAI dose for Korean GD patients with a large goiter (${\geq}33mL$) should be at least 15 mCi to achieve the best outcome.

Treatment of Radioactive Liquid Waste Using Natural Evaporator and Resulted Exposure Dose Assessment (증발을 이용한 방사성 액체폐기물의 처리와 피폭선량평가)

  • Jeong, Gyeong-Hwan;Park, Seung-Kook;Kim, Eun-Han;Jung, Ki-Jung;Park, Hyun-Soo
    • Journal of Radiation Protection and Research
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    • v.24 no.2
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    • pp.101-108
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    • 1999
  • The influence of the relative humidity, the temperature and the velocity of supply air on evaporation rate has been studied with non-boiling forced evaporation system in order to treat very low level radioactive liquid wastes produced from the decontamination and decommissioning activities. Experimental data on the evaporation rate have been obtained with the divers variables and experimental equation of air velocity was also obtained by the correlation of those data. The decontamination factor of this system was also obtained by the experimental data from a simulated liquid waste containing Cs-137 radio isotope ; $DF=10^4$. Since the commercial system will be operated for the treatment of the very low level radioactive liquid waste produced from decontamination & decommissioning of TRIGA Mark-II&III research reactor, the environmental assessment has been conducted to improve the operational safety. Exposure dose rate for an individual member of general public was assessed, and it showed that it was very lower than individual dose limits. The release of radioactivity of radioisotope material (Cs-137) to the environment was assessed, and result showed that it was $4.637{\times}10^{-14}\;{\mu}Ci/cc$.

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A Study on the Radiation Source Effect to the Radiation Shielding Analysis for a Spent-Fuel Cask Design with Burnup-Credit (연소도이득효과를 적용한 사용후핵연료 수송용기의 방사선원별 차폐영향 분석)

  • Kim, Kyung-O;Kim, Soon-Young;Ko, Jae-Hoon;Lee, Gang-Ug;Kim, Tae-Man;Yoon, Jeong-Hyun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.2
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    • pp.73-80
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    • 2011
  • The radiation shielding analysis for a Burnup-credit (BUC) cask designed under the management of Korea Radioactive Waste Management Corporation (KRMC) was performed to examine the contribution of each radiation source affecting dose rate distribution around the cask. Various radiation sources, which contain neutron and gamma-ray sources placed in active fuel region and the activation source, and imaginary nuclear fuel were all considered in the MCNP calculation model to realistically simulate the actual situations. It was found that the maximum external and surface dose rates of the spent fuel cask were satisfied with the domestic standards both in normal and accident conditions. In normal condition, the radiation dose rate distribution around the cask was mainly influenced by activation source ($^{60}Co$ radioisotope); in another case, the neutron emitted in active fuel region contributed about 90% to external dose rate at 1m distance from side surface of the cask. Besides, the contribution level of activation source was dramatically increased to the dose rates in top and bottom regions of the cask. From this study, it was recognized that the detailed investigation on the radiation sources should be performed conservatively and accurately in the process of radiation shielding analysis for a BUC cask.

Considerations on Screening for the Input Data of the Biosphere Model in the Radioactive Waste Disposal Facility (방사성폐기물 처분시설에서 생태계 모델의 입력데이터 선정에 대한 고찰)

  • Mi-Seon Jeong;Dong-Kuk Park;Soo-Gin Kim;Kang-Il Jung
    • Journal of Radiation Industry
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    • v.17 no.2
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    • pp.209-217
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    • 2023
  • The biosphere has important function in the safety assessment of a radioactive waste disposal facility. A biosphere model in the safety assessment needs various input data that contain significantly inherent uncertainties. This paper reviews the effects of the input data on the radiological impact assessment from main radionuclides such as 14C and 99Tc in the biosphere model. In addition, it is confirmed that the safety criteria is met, when the conservative input data for the intake rate, soil to plant concentration ratio, and distribution coefficients of the radionuclides are applied and probabilistic analysis are conducted in the biosphere model. Nevertheless, it is required to generate site-specific input data for the confidence building and reduce excessive conservatism in the biosphere model.