| 1. |
- Adliene, Diana, et al.
(författare)
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Assessment of the environmental contamination with long-lived radionuclides around an operating RBMK reactor station
- 2006
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 90:1, s. 68-77
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Tidskriftsartikel (refereegranskat)abstract
- The presence of man-made gamma emitting radionuclides in the region within 32 km radius of the Ignalina NPP/Lithuania has been investigated during the period 2001-2004, prior to the closure of the first 4 the two operating RBMK 1500-type reactors. Gamma spectrometric measurements of various terrestrial and aquatic plants as well as of soil samples showed moderate environmental contamination with the fission product Cs-137 and with the neutron activation products Co-60 and Mn-54. Traces of the activation products Zn-65 and Ag-110m were found in the nearest vicinity of the NPP. Activity concentrations were inhomogeneously distributed in the area of interest. Moss and algae samples showed the highest uptake of radionuclides. In addition to the gamma spectrometric measurements, the levels of C-14 were determined in the same bio-indicator samples using accelerator mass spectrometry. (c) 2006 Elsevier Ltd. All rights reserved.
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| 2. |
- Dias, C M, et al.
(författare)
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14CO2 dispersion around two PWR nuclear power plants in Brazil.
- 2009
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 100:7, s. 574-580
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Tidskriftsartikel (refereegranskat)abstract
- Atmospheric air samples were taken within 3 km from power plants encompassing five different distances and wind directions. Samples were taken between 2002 and 2005 aiming to evaluate the environmental C-14 enrichment due to the operation of Brazilian nuclear power plants. The sampling system consisted of a pump connected to a trapping column filled with a 3 M NaOH solution. The trapped C-14 by using a single stage accelerator mass spectrometry (SSAMS). CO2 was analyzed for All sampling sites revealed measurable C-14 excess values. The maximum excesses were of 15 and 14 mBq/m(3) for sampling sites placed at NE of the power plants, which is the main wind direction in the area. The mean excesses values were 12 mBq/m(3) to the NE direction, 8 mBq/m to the E, 10 mBq/m to the N, 8 mBq/m(3) to the WNW and 7 mBq/m(3) to the W direction (increasing distances from NE to W). Compared to other Light Water Reactors (LWR) data, these means' values are significantly higher than the average worldwide reported value of 3 mBq/m(3). Available data indicate that the observed values are not related to C-14 emission by the power plants vent stack. Other factors, such as topography, seem to have an important role because it affects wind dispersion thus favoring C-14 accumulation in the sampled area. Moreover, the high elevations around the power plants enhance the chances to measure high values of C-14 since the plume can be intercepted before it is drawn to the ground. Modeling of the plume has shown that its dispersion does not follow a Gaussian model and that agreement between atmospheric CO2 and vegetation C-14 activities occurs only for sampling sites placed at NE of the power plants. (c) 2009 Elsevier Ltd. All rights reserved.
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| 3. |
- Dias, Cintia Melazo, et al.
(författare)
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C-14, delta C-13 and total C content in soils around a Brazilian PWR nuclear power plant
- 2009
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 100:4, s. 348-353
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Tidskriftsartikel (refereegranskat)abstract
- Nuclear power plants release C-14 during routine operation mainly as airborne gaseous effluents. Because of the long half-life (5730 years) and biological importance of this radionuclide (it is incorporated in plant tissue by photosynthesis), several countries have monitoring programs in order to quantify and control these emissions. This paper compares the activity of C-14 in soils taken within I km from a Brazilian nuclear power plant with soils taken within a reference area located 50 km away from the reactor site. Analyses of total carbon, delta C-13 and Cs-137 were also performed in order to understand the local soil dynamics. Except for one of the profiles, the isotopic composition of soil organic carbon reflected the actual forest vegetation present in both areas. The Cs-137 data show that the soils from the base of hills are probably allocthonous. The C-14 Measurements showed that there is no accumulation due to the operation of the nuclear facility, although excess C-14 Was found in the litter taken in the area close to power plant. This indicates that the anthropogenic signal observed in the litter fall has not been transferred yet to the soil. This study is part of an extensive research programme in which other samples including air, vegetation and gaseous effluents (taken in the vent stack of the Brazilian nuclear power reactors Angra I and II) were also analyzed. The present paper aimed to evaluate how C-14 emissions from the nuclear power plant are transferred and stored by soils present in the Surroundings of the reactor site. This is the first study concerning anthropogenic 14C in soils in Brazil. (9) 2009 Elsevier Ltd. All rights reserved.
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| 4. |
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| 5. |
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| 7. |
- Gunnarsson, Mikael, et al.
(författare)
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Long-term biokinetics and radiation exposure of patients undergoing 14C-glycocholic acid and 14C-xylose breath tests.
- 2007
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 22:6, s. 762-771
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Tidskriftsartikel (refereegranskat)abstract
- The (14)C-glycocholic acid and (14)C-xylose breath tests are clinically used for the diagnosis of intestinal diseases, such as bacterial overgrowth in the small intestine. The two tests have in earlier studies been thoroughly evaluated regarding their clinical value, but due to the long physical half-life of (14)C and the limited biokinetic and dosimetric data, which are available for humans, several hospitals have been restrictive in their use. The aim of this study was to investigate the long-term biokinetics and dosimetry of the two (14)C compounds in patients and volunteers, using the highly sensitive accelerator mass spectrometry (AMS) technique. Eighteen (18) subjects were included, 9 for each compound. The (14)C content in samples from exhaled air, urine, and, for some subjects, also feces were analyzed with both liquid scintillation counting (LSC) and AMS. The results from the glycocholic acid study showed that, up to 1 year after the administration, 67%+/-6% (mean+/-standard deviation) of the administered activity was recovered in exhaled air, 2.4%+/-0.4% was found in urine, and 7.6% (1 subject) in feces. In the xylose study, the major part was found in the urine (66%+/-2%). A significant part was exhaled (28%+/-5%), and the result from an initial 72-hour stool collection from 2 of the subjects showed that the excretion by feces was insignificant. The absorbed dose to various organs and tissues and the effective dose were calculated by using biokinetic models, based on a combination of experimental data from the present study and from earlier reports. In the glycocholic acid study, the highest absorbed dose was received by the colon (1.2 mGy/MBq). In the xylose study, the adipose tissue received 0.8 mGy/MBq. The effective dose was estimated to 0.5 (glycocholic acid) and 0.07 mSv/MBq (xylose). Thus, from a radiation protection point of view, we see no need for restrictions in using the two (14)C-labeled radiopharmaceuticals on adults with the activities normally administered (0.07-0.4 MBq).
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| 8. |
- Hellborg, Ragnar, et al.
(författare)
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Vacuum in an accelerator system - calculations and measurements
- 2005
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Ingår i: Vacuum. - : Elsevier BV. - 0042-207X. ; 78:2-4, s. 427-434
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Tidskriftsartikel (refereegranskat)abstract
- The importance of different sources of gases in a vacuum system is discussed and the definitions of different flow regimes are presented. The conductance is given for a few different, typical geometries in an accelerator vacuum system. The theory is applied to the vacuum system of the Lund electrostatic tandem accelerator and a pressure profile through the accelerator is calculated. The quality of this simplified method is discussed.
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| 10. |
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