scholarly journals ORNL results for Test Case 1 of the International Atomic Energy Agency`s research program on the safety assessment of Near-Surface Radioactive Waste Disposal Facilities

1993 ◽  
Author(s):  
D.J. Thorne ◽  
L.M. McDowell-Boyer ◽  
D.C. Kocher ◽  
C.A. Little ◽  
E.K. Roemer
2014 ◽  
Vol 1665 ◽  
pp. 3-12 ◽  
Author(s):  
Michael I. Ojovan ◽  
Anthony J. Wickham

ABSTRACTAn overview is given of an International Atomic Energy Agency Coordinated Research Project (CRP) on the treatment of irradiated graphite (i-graphite) to meet acceptance criteria for waste disposal. Graphite is a unique radioactive waste stream, with some quarter-million metric tons worldwide eventually needing to be disposed of. The CRP has involved 24 organizations from 10 Member States. Innovative and conventional methods for i-graphite characterization, retrieval, treatment and conditioning technologies have been explored in the course of this work, and offer a range of options for competent authorities in individual Member States to deploy according to local requirements and regulatory conditions.


Author(s):  
Maria Visitacion Palattao ◽  
Edmundo Vargas ◽  
Rolando Reyes ◽  
Carl Nohay ◽  
Alfonso Singayan ◽  
...  

The Philippine Nuclear Research Institute (PNRI) in collaboration with the interagency technical committee on radioactive waste has been undertaking a national project to find a final solution to the country’s low to intermediate level radioactive waste. The strategy adopted was to co-locate 2 disposal concepts that will address the types of radioactive waste generated from the use of radioactive materials. This strategy is expected to compensate for the small volumes of waste generated in the Philippines as compared to countries with big nuclear energy programs. It will also take advantage of the benefits of a shared infrastructure and R&D work that accompany such project. The preferred site selected from previous site selection and investigations is underlain by highly fractured “andesitic volcaniclastics” mantled by residual clayey soil which act as the aquifer or water bearing layer. Results of investigation show that the groundwater in the area is relatively dilute and acidic. Springs at the lower elevations of the footprint also indicate acidic waters. The relatively acidic water is attributed to the formation of sulfuric acid by the oxidation of the pyrite in the andesite. A preliminary post closure safety assessment was carried out using the GMS MODFLOW and HYDRUS softwares purchased through the International Atomic Energy Agency (IAEA) technical assistance. Results from MODFLOW modeling show that the radionuclide transport follows the natural gradient from the top of the hill down to the natural discharge zones. The vault dispersion model shows a circular direction from the vaults towards the faults and eventually to the creeks. The contaminant transport from borehole shows at least one confined plume from the borehole towards the creek designated as Repo1 and eventually follows downstream. The influx of surface water and rainfall to the disposal vault was modeled using the HYDRUS software. The pressure head and water content at the base of the foundation layer and the bottom of the concrete is where a significant reduction in water content can be observed. It is also noted that water content and pressure remain constant after one year.


2020 ◽  
Vol 21 (1) ◽  
pp. 36-47
Author(s):  
Nikolai S. Pankratov ◽  
Vyacheslav V. Belov

The article deals with the selection of sites for the construction of nuclear installations, radioactive waste disposal sites and other facilities for the use of nuclear energy. The review of modern approaches to the selection of sites for placement of near-surface radioactive waste disposal points shows that the system research in this area is not fully presented, and is mainly aimed at solving problems of an engineering-geological nature for the location area, as well as the choice of materials for engineering protection barriers. In this paper, using the example of radioactive waste disposal sites, we review the requirements set by the regulatory documents of the Russian Federation and the International Atomic Energy Agency in the field of site selection. The authors proposed additions to the methodology for selecting sites for the construction of low-and medium-level waste disposal sites based on the system and GIS analysis of the ALARA principles, as well as the method of weighted evaluation of criteria and their pairwise comparisons. The multi-criteria nature of the site selection problem is proposed to be described by GIS analysis of data with drawing the corresponding limiting and preferred requirements directly on the map of the area, which is shown in the article by the example of selecting sites for radioactive waste disposal points. Taking into account the necessary requirements at various stages of the life cycle, as well as their significance, can be assessed by weighted estimates and pairwise comparisons, followed by their introduction into the GIS analysis. This approach allows to choose rational options for placing potential sites, taking into account the life cycle of the object, in a rational way, with compliance with all necessary regulatory requirements.


2021 ◽  
Vol 21 (2) ◽  
pp. 78-87
Author(s):  
B. H. Shabalin ◽  
◽  
К. К. Yaroshenko ◽  
S. P. Buhera

The main feature of bentonite clays is their high sorption capacity with respect to various radionuclides. The study of sorption kinetics of 137Cs was performed in the static mode by natural and industrial soda modified (PBA-20) samples of bentonite clays of Cherkasy deposit of bentonite and paligorskite clays from groundwater model solutions of radioactive waste disposal facilities of “Vector” production complex under various pH and solution mineralisation. The desorption of occluded samples was studied in distilled water and acetateammonium buffer solution. The value of the degree of sorption (S) for 137Cs on the modified samples exceeds 90%, for natural bentonite this indicator is lower (about 83–85%). On both types of bentonite with increasing time of their contact with aqueous solution and pH, there is a redistribution of water-soluble, ion-exchange and fixed forms of radionuclide and the share of the latter, that is not participating in migration processes increases, indicating the ability of bentonites to immobilize effectively for a long time. It is shown that Na-modified bentonite has higher proportion of sorption in fixed form compared to natural one and its application increases the probability of irreversible fixation of migrating radionuclides under non-optimal conditions of sorption (high pH (>11) of water after prolonged contact with cement-concrete components of engineering barriers) and thus increases the environmental safety of the storage facility. It is shown that bentonite clays of the Cherkasy deposit can serve as an effective material for creating anti-migration barriers of I and II stages of surface/near-surface storage facilities for radioactive waste disposal at the “Vector” production complex. At the same time, the issue of practical application of bentonite clays of Cherkasy deposit for accurate predictions of securing radioactive waste disposal of Chornobyl origin requires further study of sorption-desorption properties of bentonite clay with respect to other fission products and actinides


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