• Title/Summary/Keyword: Radioactive dose

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Alarm Setpoint Determination Method of Gaseous Effluent Radiation Monitoring Systems Using Dose Factors Based on ICRP-60 Recommendations (선량환산인자를 이용한 기체유출물 RMS 경보설정 개선방안)

  • 박규준;김희근;하각현;엄희문
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2003.11a
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    • pp.491-496
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    • 2003
  • In Korea, the dose limits to the public were reduced according to ICRP-60 recommendations. The secondary quantities, Effluent Concentration Limits (ECLs) were derived and enacted to Korean Atomic Laws based on ICRP-60 recommendations. The Korea atomic laws require assurance that radioactive materials within gaseous effluents do not exceed dose limits and ECLs. This simply means that any effluent that would possibly contain radioactivity must be monitored. There are various methods to monitor the radioactivity of effluent monitor to satisfy the dose limits and the ECLs for gaseous effluents. The many factors (safety margin) should be considered in determining of the setpoint of effluent monitor, following these limits. In this study, we studied the determination method of alarm setpoint for gaseous effluent Radiation Monitoring Systems using dose factors considered the main pathway of radionuclides to compare the preceding determination method of alarm setpoint for gaseous effluent RMSs using dose assessment program considered all the practicable pathways of radionuclides.

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Comparison the reference ion chamber in using the radioactive check source and field ion chamber for output dose for Co-60 source of remote afterloading system (시험선원을 이용한 기준 전리함의 감도변화와 임상필드전리함의 성능 안정성 비교)

  • 최태진
    • Progress in Medical Physics
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    • v.12 no.2
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    • pp.141-146
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    • 2001
  • It is well known that assurance of the radiation therapy needs for an accuracy of $\pm$ 5 % in the delivery of an absorbed dose to target volume. Therefore, the dose evaluation of brachytherapy source and/or linear accelerate beam must be a stability with accuracy. In an advanced country, they recommended to use the radioactive check source for reference air ionization chamber for a stable response of radiation field chamber. In this experiments, the radioactive source Sr-90 and PR-05 air ionization chamber were used for standard source and reference ion chamber. The response of reference ion chamber showed as an 1.000$\pm$ 0.010 uncertainty for 10 years long and the evaliuation f dose discrepancy of clinical field ion chamber showed as 0.997 $\pm$0.011 in a $^{60}$ Co brachytherapy soruce. In our experiments, we can assuarance the long halflife standard source is reliable to preserve the calibration factor of reference chamber in stability.

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Analysis of Exposure Pathways and the Relative Importance of Radionuclides to Radiation Exposure in the Case of a Severe Accident of a Nuclear Power Plant (원전 중대사고시 피폭경로 및 핵종의 방사선 피폭에 대한 상대적 중요도 해석)

  • Hwang, Won-Tae;Suh, Kyung-Suk;Kim, Eun-Han;Han, Moon-Hee;Kim, Byung-Woo
    • Journal of Radiation Protection and Research
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    • v.19 no.3
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    • pp.209-221
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    • 1994
  • In the case of a severe accident of a nuclear power plant, the whole body dose and the relative importance of the radionuclides during the lifetime of an exposed person were estimated for each exposure pathway with distances from the release point. The external exposure pathways due to immersion of radioactive cloud and deposition of radioactive materials on the ground, and the internal exposure pathways due to inhalation and ingestion of contaminated foodstuffs were considered. The effects due to the ingestion of contaminated foodstuffs were estimated considering the variation of radioactive concentration in the foodstuffs according to deposition time and elapsed time after deposition using a dynamic ingestion pathway model applicable to Korean environment, named 'KORFOOD'. As the results up to 80 km from the release point, the effects due to ingestion of contaminated foodstuffs showed the highest contribution to total exposure dose. The contribution of I isotopes was the highest in the case of the external dose due to immersion of radioactive cloud and internal dose due to inhalation. The contribution of Cs isotopes was highest in the case of the external dose due to deposition of radioactive materials on the ground. In the case of the internal dose due to ingestion of contaminated foodstuffs, Cs deposition in summer and Sr deposition in winter, respectively, were the most dominant radionuclide to whole body.

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Development of Exposure Level Prediction Program in Radioactive Waste Work (방사성 폐기물 작업 중의 피폭서량 예측 프로그램 개발)

  • Park, Won-Man;Kim, Yoon-Hyuk;Whang, Joo-Ho
    • Journal of the Ergonomics Society of Korea
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    • v.24 no.2
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    • pp.71-77
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    • 2005
  • In spite of the importance of nuclear power as one of major electric energies in Korea, the nuclear safety has become the most serious social issue in the operation of the nuclear power plant. In this paper, a virtual work simulation program was developed to predict exposure dose during radiation work in radwaste storage. The work simulation program was developed. using $Java ^{TM}$applet and VRML-virtual reality modeling language. A numerical algorithm to find the optimal work path which minimize exposure dose during the given work, was developed and exposure dose on the optimal work path was compared with that on the shortest path. Comparing with the shortest path for the given work, the predicted optimal path consumed longer work time by II% but reduced total exposure dose by 46%. The simulation result showed that the exposure dose depended on not only work time, but also the distance between the worker and the radiation source. The developed simulation program could be a useful tool for the planning of radioactive waste work to increase the radiation safety of workers.

방사성핵종 오염 토양 특성 분석 및 핵종제거 방법 연구

  • 김계남;원휘준;오원진
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.04a
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    • pp.209-212
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    • 2002
  • Main radionuclides of the soil waste stored in Korea Atomic Energy Research Institute are Co-60 and Cs-137. Moisture content of soil is 12%, pH of soil is 5.8, and content of organic matter is 2.2 %. Radioactive concentrations of the soil particle size of which is less than 0.063mm and soil in the drum surface of which is more than radiation dose rate 0.05mR/hr are higher. Meanwhile, radioactive concentration of soil in the drum surface of which is less than radiation dose rate 0.02 mR/hr are mostly lower. On using the mixing solution of ammonium sulfate and citric acid, 62% Co was removed from soil and 41% Cs was removed. Also, on using the mixing solution of ammonium nitrate and citric acid, 61% Co was removed from soil and 39% Cs was removed, and on using the mixing solution of ammonium potassium oxalate, 36% Co was removed and only 3% Cs was removed. And on using only water, removal efficiency is less than 5%.

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Physical Dosimetry in Radioactive Iodine Treatment in the Patients with Thyroid Cancer (갑상선암 환자에 대한 방사성옥소 치료시 물리적 선량 측정)

  • Kim, Myung-Seon;Jeong, Nae-In;Lee, Jai-Yong;Kim, Chong-Soon;Kim, Chong-Ho;Lee, Myung-Chul;Koh, Channg-Soon;Kim, Hee-Geun;Kang, Duck-Won;Song, Myung-Jae
    • The Korean Journal of Nuclear Medicine
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    • v.28 no.1
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    • pp.124-132
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    • 1994
  • Radioactive iodine has been widely used in patients with thyroid cancer combined with surgical treatment. However, due to individual variations in absorption and excretion and uptake by tumor tissue of radioactive iodine, there are differences in therapeutic effect and adverse effects even if the same doses are administrated. So this study compared the therapeutic effect and radiation hazard by measuring internal radiation dose. Of total 27 patients with well differentiated thyroid cancer who had been thyroidectomized, we administered radioactive iodine 100 mCi, 150 mCi, 200 mCi. According to BEL DOSIMETRY PROTO-COL, beta and gamma ray dose were estimated from a pelt of the logarithm of the percent of dose per liter of whole blood versus day, and percent dose retained versus day using somilogarithmic paper, respectively. 1) Physical dose to whole blood averaged $56.54{\pm}13.02$ rad in 100 mCi administered group, $76.83{\pm}19.97$ rad in 150 mCi administered group, $95.08{\pm}25.51$ rad in 200 mCi administered group and there has been a significant correlation among the groups. 2) Mean percent dose retained 48 hours later was 26.34%. 3) There was no significant correlation of physical dose between absence and presence of metastasis. 4) 17 of 19 patients who has been followed up with TSH and serum throglobulin, Thallium scan were successfully ablated by radioactive iodine. 5) Leukocyte, lymphocyte, neutrophil, platelet counts all deelined in 4.6 weeks and most of all were restored 3 months later. 6) There was no significant correlation between physical dosimetry and biologic dosimetry. Generally administered doses of radioactive iodine (100-200 mCi) to patients with thyroid cancer postoperatively had developed transient bone marrow suppression and minimal chromosomal aberration, but they were within safety dose to blood (200 rad). And there has been no significant differences in residual dose 48 hours later between Korean and western people.

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A new proposal for controlled recycling of decommissioning concrete waste as part of engineered barriers of a radioactive waste repository and related comprehensive safety assessment

  • In Gyu Chang;Jae Hak Cheong
    • Nuclear Engineering and Technology
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    • v.55 no.2
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    • pp.530-545
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    • 2023
  • As an alternative to conventional management options for a lot of concrete waste from decommissioning of nuclear power plants, a set of scenarios for controlled recycling of decommissioning concrete waste as engineered barriers of a radioactive waste repository was proposed, and a comprehensive safety assessment model and framework covering both pre-and post-closure phases was newly developed. The new methodology was applied to a reference vault-type repository, and the ratios of derived concentration limits to unconditional clearance levels of eighteen radionuclides for controlled recycling were provided for three sets of dose criteria (0.01, 1, and 20 mSv/y for the pre-closure and 0.01 mSv/y for the post-closure phases). It turns out that decommissioning concrete waste whose concentration is much higher than the unconditional clearance level can be recycled even when the dose criterion 0.01 mSv/y is applied. Moreover, a case study on ABWR bio-shield shows that the fraction of recyclable concrete waste increases significantly by increasing the dose criterion for the radiation worker in the pre-closure phase or the duration of storage prior to recycling. The results of this study are expected to contribute to demonstrating the feasibility of controlled recycling of a lot of decommissioning concrete waste within nuclear sectors.