• Title, Summary, Keyword: Radionuclide

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A Method to Calculate Off-site Radionuclide Concentration for Multi-unit Nuclear Power Plant Accident (다수기 원자력발전소 사고 시 소외 방사성물질 농도 계산 방법)

  • Lee, Hye Rin;Lee, Gee Man;Jung, Woo Sik
    • Journal of the Korean Society of Safety
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    • v.33 no.6
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    • pp.144-156
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    • 2018
  • Level 3 Probabilistic Safety Assessment (PSA) is performed for the risk assessment that calculates radioactive material dispersion to the environment. This risk assessment is performed with a tool of MELCOR Accident Consequence Code System (MACCS2 or WinMACCS). For the off-site consequence analysis of multi-unit nuclear power plant (NPP) accident, the single location (Center Of Mass, COM) method has been usually adopted with the assumption that all the NPPs in the nuclear site are located at the same COM point. It was well known that this COM calculation can lead to underestimated or overestimated radionuclide concentration. In order to overcome this underestimation or overestimation of radionuclide concentrations in the COM method, Multiple Location (ML) method was developed in this study. The radionuclide concentrations for the individual NPPs are separately calculated, and they are summed at every location in the nuclear site by the post-processing of radionuclide concentrations that is based on two-dimensional Gaussian Plume equations. In order to demonstrate the efficiency of the ML method, radionuclide concentrations were calculated for the six-unit NPP site, radionuclide concentrations of the ML method were compared with those by COM method. This comparison was performed for conditions of constant weather, yearly weather in Korea, and four seasons, and the results were discussed. This new ML method (1) improves accuracy of radionuclide concentrations when multi-unit NPP accident occurs, (2) calculates realistic atmospheric dispersion of radionuclides under various weather conditions, and finally (3) supports off-site emergency plan optimization. It is recommended that this new method be applied to the risk assessment of multi-unit NPP accident. This new method drastically improves the accuracy of radionuclide concentrations at the locations adjacent to or very close to NPPs. This ML method has a great strength over the COM method when people live near nuclear site, since it provides accurate radionuclide concentrations or radiation doses.

Regulatory Problems in Radionuclide Therapy and Suggestions for Systematic Improvement (방사성동위원소 치료의 제도적 문제점과 개선)

  • Jeong, Jae-Min
    • Nuclear Medicine and Molecular Imaging
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    • v.40 no.2
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    • pp.53-57
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    • 2006
  • Radionuclide therapy has been used for more than 50 years and proved to be a safe and effective modality. However, the patients' right to have the excellent medical service is seriously disturbed by excessive regulations of government institutions such as Korea Institute of Nuclear Safety (KINS), Health Insurance Review Agency (HIRA) and Korea Food and Drug Administration (KFDA). For example, the patients should wait for more than 6 months to have I-131 treatment in many hospitals it is strongly recommended to mitigate the regulations to resonable levels to solve the problems. If HIRA allow the hospitals to charge reasonable rate for radionuclide therapy room, then more hospitals would invest to build the radionuclide therapy rooms and the patients' waiting time would decrease. The waiting time would also decrease, if KINS allow 2 patients to share a radionuclide therapy room. Finally, it is strongly recommended to lower the threshold for approval of new therapeutic radiopharmaceuticals by KFDA, which would allow new effective therapeutic raoiopharmaceuticals to be introduced to clinical practices more easily.

A Theoretical Approach on the Migration of a Chelating Radionuclide in Porous Medium (다공성 매질에서의 착화하는 방사성핵종의 이동에 대한 이론적 접근)

  • Baik, Min-Hoon;Lee, Kun-Jai
    • Journal of Radiation Protection and Research
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    • v.17 no.2
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    • pp.49-59
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    • 1992
  • A new model was developed in order to investigate the effects of chelating agents on the migration of a radionuclide in the form of ion or chelate. The migration behavior of the chelated radionuclide was analyzed by formulating a convective-dispersion transport equation which included a degradation of chelating agent and chelated radionuclide. The mathematical model was analytically solved and checked with the existing retardation factor. The results show that the migration velocity of the chelated radionuclide was much faster than the ionic one due to the decreased retardation. Therefore, it was concluded that a new remedial action should be developed to reduce the generation and release of chelating agents from the nuclear power plant into the environment.

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Radionuclide Angiocardiography in Cogenital Heart Disease (선천성심질환(先天性心疾患)에서 방사성(放射性) 동위원소심혈관조영술(同位元素心血管造影術) -좌우단락(左右短絡)의 발견(發見)과 정량(定量)에 대하여-)

  • Kim, Byung-Chan;Noh, Byung-Suk;Sohn, Myung-Hee;Song, Ho-Yung;Kim, Chong-Soo;Kim, Jong-Keon;Choi, Ki-Chul
    • The Korean Journal of Nuclear Medicine
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    • v.20 no.1
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    • pp.85-91
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    • 1986
  • In detecting, localizing and quantitating cardiac shunts, radionulide angiocardiography has been known to be a simple and safe method compared with oxymetry method. To ascertain the availability of the results obtained by radionuclide angiocardiography for the evaluation of patients with cardiac shunt, author compared the Qp/Qs ratios(pulmonary to systemic flow ratios) obtained by radionuclide angiocardiography with the results of oximetry method in 40 patients with left to right shunt, and also compared the results of radionuclide angiocardiography examined before and after shunt operation in 8 patients. The results were as follows: 1) Of the 161 patients examined radionuclide angiocardiography, 98 were thought to have cardiac shunts: right to left shunt id 27, left to right shunt in 71. Of the 71 patients who had left to right shunt, 40 who were examined with both radionuclide angiocardiography and oxymetry had following congenital heart disease: VSD in 21, ASD in 9 and PDA in 10. 2) Comparison of Qp/Qs ratios obtained during radionuclide angiocardiography and oxymetry revealed good correlation (linear regression analysis yielded correlation coefficient of 0.80) in 32 patients whose Qp/Qs ratio obtained during oxymetry were below 3.0, but very poor correlation in 8 patients whose Qp/Qs ratios were above 3.0 3) Radionuclide angiocardiography is a relatively safe and simple method in postoperative evaluation of patients with cardiac shunt.

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Three-dimensional MXene (Ti3C2Tx) Film for Radionuclide Removal From Aqueous Solution

  • Jang, Jiseon;Lee, Dae Sung
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • pp.379-379
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    • 2018
  • MXenes are a new family of 2D transition metal carbide nanosheets analogous to graphene (Lv et al., 2017; Sun et al., 2018). Due to the easy availability, hydrophilic behavior, and tunable chemistry of MXenes, their use in applications for environmental pollution remediation such as heavy metal adsorption has recently been explored (Li et al., 2017). In this study, three-dimensional (3D) MXene ($Ti_3C_2T_x$) films with high adsorption capacity, good mechanical strength, and high selectivity for specific radionuclide from aquose solution were successfully fabricated by a polymeric precursor method using vacuum-assisted filtration. The highest removal efficiency on the films was 99.54%, 95.61%, and 82.79% for $Sr^{2+}$, $Co^{2+}$, and $Cs^+$, respectively, using a film dosage of 0.06 g/ L in the initial radionuclide solution (each radionuclide concentration = 1 mg/L and pH = 7.0). Especially, the adsorption process reached an equilibrium within 30 min. The expanded interlayer spacing of $Ti_3C_2T_x$ sheets in MXene films showed excellent radionuclide selectivity ($Cs^+$ and/or $Sr^{2+}/Co^{2+}$) (Simon, 2017). Besides, the MXene films was not only able to be easily retrieved from an aqueous solution by filtration after decontamination processes, but also to selectively separate desired target radionuclides in the solutions. Therefore, the newly developed MXene ($Ti_3C_2T_x$) films has a great potential for radionuclide removal from aqueous solution.

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Diagnostic Significance of Radionuclide Venography - A Comparison with X-ray Contrast Venography - (방사성동위원소정맥촬영술(放射性同位元素靜脈撮影術)의 진단적(診斷的) 의의(意義) - X-선정맥조영술(線靜脈造影術)과의 비교(比較) 연구(硏究) -)

  • Bae, S.H.;Park, J.H.;Han, M.C.;Cho, B.Y.;Koh, C.S.
    • The Korean Journal of Nuclear Medicine
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    • v.15 no.2
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    • pp.19-25
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    • 1981
  • Radionuclide venographies were performed in 138 limbs of 58 patients and X-ray contrast venographies were performed in 23 paitents of them. Positive radionuclide venography findings were area of decreased sponding to the region of thrombosis, abnormal collateral flows below the lesion. The success rate of radionulide venography was 89% and the overall concordance between radionuclide venography and X-ray contrast venography was 91%. Radionuclide venography is simple and easy to perform and less invasive than X-ray contrast venography. These results indicate that radionuclide venography is the most ideal screening test for the detection of venous thrombosis in patient with signs & symptoms of deep vein thrombosis.

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7 Cases of Incidental Radionuclide Uptake in the Gabtrointestinal Tract During $^{99m}Tc$-Methylene Diphosphonate Bone Scintigraphy ($^{99m}Tc$-MDP 골 스캔 중 발견된 위 및 장관의 섭취증가 7예)

  • Son, Tae-Yong;Kim, Hyung-Gun;Yuh, Young-Jin;Lee, Sang-Goo;Cheon, Eun-Mee;Lim, Sang-Moo;Hong, Sung-Woon
    • The Korean Journal of Nuclear Medicine
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    • v.27 no.2
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    • pp.315-318
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    • 1993
  • We experienced 7 cases of patients who were performed $^{99m}Tc$-methylene diphosphonate bone scintigraphy for the evaluation of diseases they had. Their bone scintigrams showed incidental radionuclide uptake in the gastrointestinal tracts and they had no special symptom or sign attributable to the findings. Case 1 showed radionuclide uptake in the stomach and both lung and the patient had suffered from hypercalcemia and azotemia. Case 3 and case 6 showed diffuse radionuclide uptake in the stomach and intestinal tract. Others showed diffuse or regional radionuclide uptake in the intestinal tracts. Radionuclide uptake in the gastrointestinal tract by $^{99m}Tc$-methylene diphosphonate is caused by a certain pathologic lesion but also can be seen in the normal gastrointestinal tract. So, one who reads bone scintigrams should be alert for the pathologic lesion in the gastrointestinal tract although one must interpretate with the concept of this normal variations.

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Numerical Estimates of Seasonal Changes of Possible Radionuclide Dispersion at the Kori Nuclear Power Plants (고리 원자력 발전 단지 사고 발생에 따른 방사능 물질 확산 가능성의 계절적 특성 연구)

  • Kim, Ji-Seon;Lee, Soon-Hwan;Park, Kang-Won;Lee, Sung-Gwang;Choi, Se-Young;Cho, Kyu-Chan;Lee, Hyeuk-Woo
    • Journal of Environmental Science International
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    • v.27 no.6
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    • pp.425-436
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    • 2018
  • To establish initial response scenarios for nuclear accidents around the Kori nuclear power plants, the potential for radionuclide diffusion was estimated using numerical experiments and statistical techniques. This study used the numerical model WRF (Weather Research and Forecasting) and FLEXPART (Flexible Particle dispersion model) to calculate the three-dimensional wind field and radionuclide dispersion, respectively. The wind patterns observed at Gijang, near the plants, and at meteorological sites in Busan, were reproduced and applied to estimates of seasonally averaged wind fields. The distribution of emitted radionuclides are strongly associated with characteristics of topography and synoptic wind patterns over nuclear power plants. Since the terrain around the power plants is complex, estimates of radionuclide distribution often produce unexpected results when wind data from different sites are used in statistical calculations. It is highly probable that in the summer and autumn, radionuclides move south-west, towards the downtown metropolitan area. This study has clear limitations in that it uses the seasonal wind field rather than the daily wind field.

Review of Radionuclide Treatment for Neuroendocrine Tumors (신경내분비종양의 방사성핵종 치료)

  • Jeong, Hwan-Jeong
    • Nuclear Medicine and Molecular Imaging
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    • v.40 no.2
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    • pp.90-95
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    • 2006
  • Neuroendocrine tumors (NETs) consist of a heterogeneous group of tumors that are able to uptake neuroamine and/or specific receptors, such as somatostatin receptors, which can play important roles of the localization and treatment of these tumors. When considering therapy with radionuclides, the best radioligand should be carefully investigated. $^{131}I$-MIBG and beta-particle emitter labeled somatostatin analogs are well established radionuclide therapy modalities for NETs. $^{111}In,\;^{90}Y\;and\;^{177}Lu$ radiolabeled somatostatin analogues have been used for treatment of NETs. Further, radionuclide therapy modalities, for example, radioimmunotherapy, radiolabeled peptides such as minigastrin are currently under development and in different phases of clinical investigation. for all radionuclides used for therapy, long-term and survival statistics are not yet available and only partial tumour responses have been obtained using $^{131}I$-MIBG and $^{111}In$-octreotide. Experimental results using $^{90}Y$-DOTA-lanreotide as well as $^{90}Y-DOTA-D-Phe1-Tyr^3-octreotide$ and/or $^{177}Lu-DOTA-Tyr^3-octreotate$ have indicated the possible clinical potential of radionuclides receptor-targeted radiotherapy it may be hoped that the efficacy of radionuclide therapy will be improved by co-administration of chemotherapeutic drugs whose antitumoral properties may be synergistic with that of irradiation.

Development of a Computer Code for Low-and Intermediate-Level Radioactive Waste Disposal Safety Assessment

  • Park, J.W.;Kim, C.L.;Lee, E.Y.;Lee, Y.M.;Kang, C.H.;Zhou, W.;Kozak, M.W.
    • Journal of Radiation Protection and Research
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    • v.29 no.1
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    • pp.41-48
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    • 2004
  • A safety assessment code, called SAGE (Safety Assessment Groundwater Evaluation), has been developed to describe post-closure radionuclide releases and potential radiological doses for low- and intermediate-level radioactive waste (LILW) disposal in an engineered vault facility in Korea. The conceptual model implemented in the code is focused on the release of radionuclide from a gradually degrading engineered barrier system to an underlying unsaturated zone, thence to a saturated groundwater zone. The radionuclide transport equations are solved by spatially discretizing the disposal system into a series of compartments. Mass transfer between compartments is by diffusion/dispersion and advection. In all compartments, radionuclides ate decayed either as a single-member chain or as multi-member chains. The biosphere is represented as a set of steady-state, radionuclide-specific pathway dose conversion factors that are multiplied by the appropriate release rate from the far field for each pathway. The code has the capability to treat input parameters either deterministically or probabilistically. Parameter input is achieved through a user-friendly Graphical User Interface. An application is presented, which is compared against safety assessment results from the other computer codes, to benchmark the reliability of system-level conceptual modeling of the code.