• Title/Summary/Keyword: Radionuclides

Search Result 595, Processing Time 0.026 seconds

The Distribution and Behavior of Medically-derived 131I in the Yeongsan River Basin (영산강수계 의료기원 방사성요오드(131I) 핵종의 분포 및 거동평가)

  • Kang, Tae-Woo;Han, Young-Un;Park, Won-Pyo;Song, Kwang-Duck;Hwang, Soon-Hong;Kang, Tae Gu;Kim, Kyung Hyun
    • Korean Journal of Environmental Agriculture
    • /
    • v.37 no.4
    • /
    • pp.243-250
    • /
    • 2018
  • BACKGROUND: Recently, the use of $^{131}I$ for diagnosis and treatment of thyroid cancer has been increasing, and the radionuclide is continuously released into aquatic ecosystem. This study was carried out to investigate the $^{131}I$ concentrations in mainstreams, tributaries, and sewage wastewater treatment plants (SWTPs) of the Yeongsan River Basin and to identify their origins from the assessment of behaviors in the rivers. METHODS AND RESULTS: The water samples were collected from 19 sites including mainstreams (13), tributaries (4) and SWTPs (2). The $^{131}I$ concentration was measured using a gamma-ray spectrometry with a HPGe detector. The $^{131}I$ in SWTPs was detected mostly in the discharged effluent at the sampling sites. However, from the surface water of the rivers, $^{131}I$ was found only at two sites from each sampling period of the first (MS4 and MS10) and the second half (MS4 and MS7) of the year 2017. The concentrations of $^{131}I$ in the effluent discharged from SWTPs were in the range of 0.0870 to 3.87 Bq/L for SWTP1, and $^{131}I$ in the river revealed that it was not detected in the upper streams of the mainstreams and tributaries, while continuous detection was found in the SWTPs and downstream sites affected by the effluent. However, the concentration of $^{131}I$ decreased downstream, eventually becoming undetectable. Such behavior was closely related to the behavior found in the SWTPs. CONCLUSION: These results indicated that medically-derived $^{131}I$ was discharged to the river via sewage effluent at the SWTPs. It is necessary to evaluate the influence of aquatic ecosystems through continuous monitoring in the future.

Activation Evaluation of Radiation Shield Wall (Concrete) in Cyclotron room using the Portable Nclide Analyzer Running Title: Activation Evaluation of Concrete in Cyclotron room (휴대용 핵종분석기를 활용한 사이클로트론실 내 차폐벽 방사화 평가)

  • Kim, Seongcheol;Gwon, Da Yeong;Jeon, Yeoryeong;Han, Jiyoung;Kim, Yongmin
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.25 no.2
    • /
    • pp.41-47
    • /
    • 2021
  • Purpose There are many cyclotrons compared to the land area of the Republic of Korea. Because GMP certification is required and the nuclear medicine test does not apply for insurance, the number of examinations for nuclear medicine is decreasing. Therefore, there is a high probability of early decommissioning of the cyclotron. However, we do not unusually perform the radioactivation evaluation on concrete that can be classified as radioactive waste during the decommissioning of the cyclotron. In this study, we aim to confirm the radioactivation in the concrete surface using Handheld Radionuclide Identification Devices (RIDs). Materials and Methods Because there is no cyclotron being decommissioning in the Republic of Korea, it was impossible to perform the coring of concrete for radioactivation analysis. In this study, we used the KIRAMS-13 and analyzed the concrete surface in the target direction in the cyclotron room. After setting the target direction as the center, radionuclides were measured for about five months at thirty points with vertical and horizontal intervals of 30 cm. We used the RIIDEye(Detector: NaI(Tl) detector, manufacturer: Thermo) in this study and set the measurement time per point to one day (24 hours). Results Co-60 and Cs-137 were detected in some measurement points, and we confirmed the radioactivity of Co-60 detected at the most points. As a result, we found that the radioactivity of Co-60 was high in the diagonal direction (from the lower-left direction to the upper right direction) based on the center of the target. However, we think it is impossible to apply the corresponding results to all cyclotrons because we performed the study using only one cyclotron. Conclusion In thirty measurement points, we could confirm the radioactive nuclides and the relative radioactivity using the results of portable nuclides analyzer. Therefore, we expect that we can use the portable nuclides analyzer to select the coring position of concrete during the decommissioning of the cyclotron. Also, if we secure the radioactivation data for several years, we expect to make a more accurate estimate of radioactive waste during the preparation period of decommissioning of the cyclotron.

Cesium Sorption to Granite in An Anoxic Environment (무산소 환경에서의 화강암에 대한 세슘 수착 특성 연구)

  • Cho, Subin;Kwon, Kideok D.;Hyun, Sung Pil
    • Korean Journal of Mineralogy and Petrology
    • /
    • v.35 no.2
    • /
    • pp.101-109
    • /
    • 2022
  • The mobility and transport of radioactive cesium are crucial factors to consider for the safety assessment of high-level radioactive waste disposal sites in granite. The retardation of radionuclides in the fractured crystalline rock is mainly controlled by the hydrochemical condition of groundwater and surface reactions with minerals present in the fractures. This paper reports the experimental results of cesium sorption to the Wonju Granite, a typical Mesozoic granite in Korea, performed in an anaerobic chamber that mimics the anoxic environment of a deep disposal site. We measured the rates and amounts of cesium (133Cs) removed by crushed granite samples in different electrolyte (NaCl, KCl, and CaCl2) solutions and a synthetic groundwater solution, with variations in the initial cesium concentration (10-5, 5×10-6, 10-6, 5×10-7 M). The cesium sorption kinetic and isotherm data were successfully simulated by the pseudo-second-order kinetic model (r2= 0.99) and the Freundlich isotherm model (r2= 0.99), respectively. The sorption distribution coefficient of granite increased almost linearly with increasing biotite content in granite samples, indicating that biotite is an effective cesium scavenger. The cesium removal was minimal in KCl solution compared to that in NaCl or CaCl2 solution, regardless of the ionic strength and initial cesium concentration that we examined, showing that K+ is the most competitive ion against cesium in sorption to granite. Because it is the main source mineral of K+ in fracture fluids, biotite may also hinder the sorption of cesium, which warrants further research.

The difference of image quality using other radioactive isotope in uniformity correction map of myocardial perfusion SPECT (심근 관류 SPECT에서 핵종에 따른 Uniformity correction map 설정을 통한 영상의 질 비교)

  • Song, Jae hyuk;Kim, Kyeong Sik;Lee, Dong Hoon;Kim, Sung Hwan;Park, Jang Won
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.19 no.2
    • /
    • pp.87-92
    • /
    • 2015
  • Purpose When the patients takes myocardial perfusion SPECT using $^{201}Tl$, the operator gives the patients an injection of $^{201}Tl$. But the uniformity correction map in SPECT uses $^{99m}Tc$ uniformity correction map. Thus, we want to compare the image quality when it uses $^{99m}Tc$ uniformity correction map and when it uses $^{201}Tl$ uniformity correction map. Materials and Methods Phantom study is performed. We take the data by Asan medical center daily QC condition with flood phantom including $^{201}Tl$ 21.3 kBq/mL. After postprocessing with this data, we analyze CFOV integral uniformity(I.U) and differential uniformity(D.U). And we take the data with Jaszczak ECT Phantom by American college of radiology accreditation program instruction including $^{201}Tl$ 33.4 kBq/mL. After post processing with this data, we analyze spatial Resolution, Integral Uniformity(I.U), coefficient of variation(C.V) and Contrast with Interactive data language program. Results In the flood phantom test, when it uses $^{99m}Tc$ uniformity correction map, Flood I.U is 3.6% and D.U is 3.0%. When it uses $^{201}Tl$ uniformity correction map, Flood I.U is 3.8% and D.U is 2.1%. The flood I.U is worsen about 5%, but the D.U is improved about 30% inversely. In the Jaszczak ECT phantom test, when it uses $^{99m}Tc$ uniformity correction map, SPECT I.U, C.V and contrast is 13.99%, 4.89% and 0.69. When it uses $^{201}Tl$ uniformity correction map, SPECT I.U, C.V and contrast is 11.37%, 4.79% and 0.78. All of data are improved about 18%, 2%, 13% The spatial resolution was no significant changes. Conclusion In the flood phantom test, Flood I.U is worsen but Flood D.U is improved. Therefore, it's uncertain that an image quality is improved with flood phantom test. On the other hand, SPECT I.U, C.V, Contrast are improved about 18%, 2%, 13% in the Jaszczak ECT phantom test. This study has limitations that we can't take all variables into account and study with two phantoms. We need think about things that it has a good effect when doctors decipher the nuclear medicine image and it's possible to improve the image quality using the uniformity correction map of other radionuclides other than $^{99m}Tc$, $^{201}Tl$ when we make other nuclear medicine examinations.

  • PDF

Effect of Eddy on the Cycle of 210Po and 234 in the central Region of Korean East Sea (동해 중부해역에서 210Po과 234Th의 순환에 대한 소용돌이의 영향)

  • YANG, HAN SOEB;KIM, SOUNG SOO;LEE, JAE CHUL
    • 한국해양학회지
    • /
    • v.30 no.4
    • /
    • pp.279-287
    • /
    • 1995
  • The vertical profiles of natural 210Pb, 210Po and 234Th activities were measured for the upper 100 m of water column at three stations in the middle region of the Korean East Sea during May 1992. And the distribution of these radionuclides was discussed associated with the formation of warm eddy or water mass. The main thermocline was maintained between the depth of 50 and 100 m at the southern station (Sta. A1), and between the depth of 10 to 50 m at the coastal station of Sockcho (Sta. B10). Contrastingly, a main thermocline at Sta. A10, which locates near the center of warm eddy, was observed below 230 m depth. Between 50 and 220 m depth of Sta. A10 is there a relatively homogeneous water mass of 10.1${\pm}$0.5$^{\circ}C$, which is significantly higher in temperature and lower in nutrient than the other two stations. It seems to be due to sinking of the warm surface water in which nutrients were completely consumed. Both 210Pb and 210Po show the highest concentration at Sta. A1 and the lowest at Sta. B10 among the three stations. Also, the 210Pb activity is generally higher in the upper layer than in the lower layer, while 210Po activity represents the reversed pattern at all three stations. At Sta. A1 and Sta. B10, the activities of 210Po relative to its parent 210Pb were deficient in the water column above the main thermocline, but were excess below the thermocline. However, the station near the center of warm eddy(Sta. A10), shows no excess of 210Po in the depths below 50 m, although its defficiency is found in the upper layer like the other stations. At Sta. A1 and b10. 234Th activities are slightly lower in the surface mixed layer than in the deeper region However, at Sta. A10, 234Th activity in the upper 30 m is higher than below 50 m or in the same depth of the other stations, probably because of the high concentration of particulate matter. The residence time of 210Po in the surface mixed layer at Sta. A10 is 0.4 year, much shorter than at the other two stations(about one year). Above 100 m depth, the residence times of 234Th range from 18 to 30 other two stations(about on year). Above 100 m depth, the residence times of 234Th range from 18 to 30 days at all stations, without significant regional variation. The percentages of recycled 210Po within the thermocline are 39% and 92% at Sta. A1 and Sta. B10, respectively. Much higher value at Sta. B10 may be due to a thin thickness of the mixed layer as well as the slower recycling rate of 210Po in the main thermocline.

  • PDF