3-D gamma dose rate reconstruction for a radioactive waste processing facility using sparse and arbitrarily-positioned measurements

2021 ◽  
pp. 104073
Author(s):  
Shangzhen Zhu ◽  
Jianzhu Cao ◽  
Sheng Fang ◽  
Xinwen Dong ◽  
Wenqian Li ◽  
...  
Author(s):  
Sabeeha JB ◽  
Mohammed GHK ◽  
Battawi SM ◽  
Falah SHHU ◽  
Ahmad JH ◽  
...  

2009 ◽  
Vol 44 (5) ◽  
pp. 777-784 ◽  
Author(s):  
U. Stöhlker ◽  
M. Bleher ◽  
T. Szegvary ◽  
F. Conen
Keyword(s):  

Author(s):  
Zhihong Zhang ◽  
Xiaobin Xia ◽  
Jianhua Wang ◽  
Changyuan Li

Molten salt reactor (MSR) system, a candidate of the Generation IV reactors, has inherent safety, on-line refueling and good neutron economy as typical advantages. An optimized MSR is developed by changing the size of fuel channel and the graphite-to-molten salt volume radio, based on the Molten-Salt Reactor Experiment (MSRE), which was originally developed at the Oak Ridge National Laboratory (ORNL). In this paper, shielding calculations for the optimized MSR are presented. The goal of this study is to determine the necessary shielding to decrease the neutron and gamma dose rate to the acceptable level according to national regulations. The operating temperature of the optimized MSR is designed in the range of 500 °C–700 °C, heat removal is also considered in the shielding design. The shielding calculations are carried out by using Monte Carlo method. The shielding system of the optimized MSR consists of 7 zones: the core, the core can, the reactor vessel, the thermal shield, the reactor cell containment, the shield tank and the concrete wall. The combinations of shielding materials in the thermal shield were evaluated. The thermal shield filled with carbon steel balls and circulating water gets an excellent shielding performance and heat removing effects. The neutron spectra and dose distributions, as well as the energy deposition over different shields have been analyzed. The total neutron dose rate outside the thermal shield is attenuated by a factor of about 104, and the gamma dose rate by a factor of about 103. These results show that the shielding design could low dose rate to an acceptable level outside the shielding and far below dose limit required.


2021 ◽  
Author(s):  
Giorgia Cinelli ◽  
Peter Bossew ◽  
Marc De Cort ◽  
Valeria Gruber ◽  
Tore Tollefsen

<p>As the scientific and knowledge service of the European Commission, the mission of the Joint Research Centre (JRC) is to support EU policies with independent evidence throughout the whole policy cycle. In particular, the JRC provides this support to the Directorate General for Energy by collecting, evaluating and reporting artificial environmental radioactivity measurements both for routine (REM database) and emergency preparedness (European Radiological Data Exchange Platform) purposes.<br>However, with the exception of potential large scale nuclear accidents, natural ionizing radiation is the largest contributor to the collective effective dose received by the world population. To gain a clearer overview of the natural sources of radioactivity, the JRC launched the European Atlas of Natural Radiation with the aim to provide insight into geographical variability of exposure components and their relative importance for total exposure to ionizing radiation.</p><p>The Atlas presents contributions from 100 experts in various fields, from 60 institutions such as universities, research centres, national and European authorities, and international organizations. In the first place, this Atlas aims to provide reference values and generate harmonised data for the scientific community and national competent authorities. It also offers an opportunity to the public to become familiar with the radioactive part of its natural environment. Intended as an encyclopaedia on natural radioactivity, the Atlas explains its different sources, i.e. cosmic and terrestrial radiation, and describes the current state-of-the art of knowledge by means of text, graphics and maps.</p><p>Being responsible for half of the natural dose, particular attention has been given to indoor radon, of which over one million measurements of long-term indoor radon concentration in ground-floor rooms of dwellings from 36 European countries were collected and aggregated as means within 10 km × 10 km grid cells. The updated version of the European Indoor Radon Map (December 2020) will be presented as well as the statistical analysis of the input data.</p><p>Geogenic Radon Potential and Geogenic Radon Hazard Index quantify the contribution of geogenic to indoor radon and are constructed using geogenic quantities, such as uranium concentrations in the ground, geology, soil permeability, soil radon concentration and terrestrial gamma dose rate.<br>Therefore, it was decided to focus the Atlas on the development of maps that display natural sources of radiation and also serve as quantities which predict geogenic radon. Maps of uranium, thorium and potassium concentrations in soil, covering most European countries, were created, while maps of uranium, thorium and potassium concentrations in bedrock are only available for some countries. A methodology for estimating the terrestrial gamma dose rate (based on ambient dose equivalent rate measurements) has been established, while the European terrestrial gamma dose rate map has been created using uranium, thorium and potassium concentration in soil. The practical use of the maps of the Atlas as geogenic quantities will be illustrated through different examples of scientific studies.</p><p>The Atlas is available in digital format and can be ordered as a printed version at https://remon.jrc.ec.europa.eu/ .</p><p> </p>


2020 ◽  
Vol 190 (2) ◽  
pp. 185-192
Author(s):  
C G Poojitha ◽  
B K Sahoo ◽  
K E Ganesh ◽  
T S Pranesha ◽  
B K Sapra

Abstract In this paper, we intend to evaluate the rate of radon and thoron exhalation from soil with reference to the underlying bedrock and gamma dose rate in the environment of elevated granitic hill—Nandi hills of Karnataka. The measurement of exhalation rates for all the soil samples collected from study area was carried out using a continuous radon–thoron monitor (Smart RnDuo monitor). The surface exhalation rate of thoron from soil samples were found to vary from 4160 ± 326 to 21 822 ± 634 mBq m−2 s−1. The mass exhalation rate of radon from soil samples were found to vary from 76 ± 6 to 269 ± 19 mBq kg−1 h−1. Concentrations of radon activity measurements were carried out for all the groundwater samples from study area. A detailed analysis along with physicochemical parameters of water has been made and discussed in this research paper.


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