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  • 1 Waste Disposal Department, Fuel Chemistry and Waste Management Division, Nuclear Research Institute Řež plc, 250 68 Husinec-Řež, Czech Republic
  • | 2 Department of Nuclear Chemistry, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University, 115 19 Prague, Czech Republic
  • | 3 Department of Analytical Chemistry, Institute of Chemical Technology in Prague, Technická 5, 166 28 Prague 6, Czech Republic
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Abstract  

Repositories for radioactive wastes are sited in the environment with very low permeability. One of the most important processes leading to the release of radionuclides to the environment is therefore diffusion of radionuclides in both natural and engineered barriers. Data for its description are crucial for the results of safety assessment of these repositories. They are obtained usually by comparison of the results of laboratory diffusion experiments with analytical and/or numerical solution of the diffusion equation with specified initial and boundary conditions. Results of the through-diffusion experiments are obviously evaluated by the “time-lag” method that needs for most of sorbing species unfortunately very long time of the experiment duration. In this paper a modified approach is proposed for the evaluation of diffusion data for safety assessment, which decreases the influence of propagation uncertainties using incorrect data and reduces time for acquiring data for safety assessment. This approach consist in the following steps: (i) experimental measurement of material diffusion parameters under various conditions using non-sorbing tritiated water or chlorine for which it is easy to reach conditions under which the “time-lag” method of evaluation of the result of the through-diffusion experiment is applicable—this step provides well established diffusion characteristics of materials for neutral species and anions, then (ii) to evaluate sorption isotherms for sorbing radionuclides from batch experiments under conditions corresponding to composition of material pore water, (iii) to assess the values of effective and apparent diffusion coefficients for sorbing radionuclides from well-defined diffusion coefficients of species in free water and (iv) to verify the obtained results using relatively short-term diffusion experiments with sorbing radionuclides, which will be evaluated using the time dependent decrease of the concentration in the input reservoir of the diffusion cell. A numerical model of the diffusion cell can model the decrease of concentration of species. The code, which we used for this type of evaluation of diffusion experiment, is based on the same approach to modelling that we use for modelling of the diffusion transport in performance assessment studies. The advantage of this approach consists in the compatibility of the approaches used for both evaluation and verification of the laboratory diffusion experiments and performance assessments and in considerable less time needed for experiments.

Manuscript Submission: HERE

  • Impact Factor (2019): 1.137
  • Scimago Journal Rank (2019): 0.360
  • SJR Hirsch-Index (2019): 65
  • SJR Quartile Score (2019): Q3 Analytical Chemistry
  • SJR Quartile Score (2019): Q3 Health, Toxicology and Mutagenesis
  • SJR Quartile Score (2019): Q2 Nuclear Energy and Engineering
  • SJR Quartile Score (2019): Q3 Pollution
  • SJR Quartile Score (2019): Q3 Public Health, Environmental and Occupational Health
  • SJR Quartile Score (2019): Q3 Radiology, Nuclear Medicine and Imaging
  • SJR Quartile Score (2019): Q3 Spectroscopy
  • Impact Factor (2018): 1.186
  • Scimago Journal Rank (2018): 0.408
  • SJR Hirsch-Index (2018): 60
  • SJR Quartile Score (2018): Q2 Nuclear Energy and Engineering
  • SJR Quartile Score (2018): Q2 Pollution

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Journal of Radionalytical and Nuclear Chemistry
Language English
Size A4
Year of
Foundation
1968
Volumes
per Year
4
Issues
per Year
12
Founder Akadémiai Kiadó
Founder's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
Publisher Akadémiai Kiadó
Springer Nature Switzerland AG
Publisher's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
CH-6330 Cham, Switzerland Gewerbestrasse 11.
Responsible
Publisher
Chief Executive Officer, Akadémiai Kiadó
ISSN 0236-5731 (Print)
ISSN 1588-2780 (Online)