scholarly journals Radioactive waste isolation in salt: peer review of the Office of Nuclear Waste Isolation's report on Functional Design Criteria for a Repository for High-Level Radioactive Waste

1984 ◽  
Author(s):  
D.F. Hambley ◽  
J.E. Russell ◽  
J.S. Busch ◽  
W. Harrison ◽  
D.E. Edgar ◽  
...  
Challenges ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 14
Author(s):  
Bella Y. Zubekhina ◽  
Boris E. Burakov ◽  
Michael I. Ojovan

We examined the degradation of nuclear waste borosilicate and phosphate glasses containing strong alpha-emitter 238Pu at a specific activity of 6.33 × 105 MBq/g in comparison with similar non-radioactive, non-radioactive irradiated and radioactive samples containing beta- and gamma-emitters, namely radionuclides 134Cs and 137Cs. For irradiation and leaching experiments, we used borosilicate and phosphate glasses, which are well-known and currently used to immobilize high-level radioactive waste. The main focus was the observation of the surface of altered glasses. Comparative analysis of hydrolytic surface alteration of borosilicate and phosphate nuclear waste glasses reveals that the behavior of radioactive samples differs significantly from that of non-radioactive glasses.


2020 ◽  
Author(s):  
Axel Liebscher ◽  
Christoph Borkel ◽  
Ute Maurer-Rurack ◽  
Michael Jendras

<p>The German Site Selection Act (Standortauswahlgesetz – StandAG) defines the search for and selection of the national German site with best possible safety for a disposal facility for high-level radioactive waste. The Federal Office for the Safety of Nuclear Waste Management (BASE) is the federal regulatory authority for radioactive waste disposal. BASE supervises the site selection process for a repository for high-level radioactive waste and is responsible for the accompanying public participation. To fulfill its tasks according to the state of science and technology, task related research forms an integral part of BASEs activities. Current research activities in the context of the site selection process address geoscientific questions, methodological aspects of the implementation of the site selection process, and public participation aspects. This contribution provides an overview on the current geoscientific and methodological research activities of BASE.</p><p>According to § 16 StandAG , the national implementer (Bundesgesellschaft für Endlagerung  mbH) has to execute surface-based exploration and BASE has to review and define the respective exploration program. Therefore, the two projects <em>MessEr</em> and <em>übErStand</em> compiled state of science and technology with regard to surface based exploration methods. The foci were on methods suitable for addressing the criteria and requirements set out in the German Site Selection Act.</p><p>The project <em>KaStör</em> reviewed the current knowledge on active faults and fault zones in Germany and studied methodological approaches to date and identify the activity of faulting. The results support BASE to review the application of the exclusion criteria for areas with “active faults zones” according to § 22 (2) StandAG.</p><p>For the time being, § 27 (4) StandAG defines 100 °C as precautionary maximum temperature at the outer surface of waste canisters for all host rocks. The project <em>Grenztemperatur</em> compiled and studied the temperature dependency of the different THMC/B processes according to available FEP catalogues for rock salt, clay stone, and crystalline rock. The project also identified open and pending research questions and describes ways to define host rock specific maximum temperatures based on specific disposal and safety concepts.</p><p>During the site selection process, safety oriented weighting of different criteria and comparison of different potential regions and sites have to be performed. The project <em>MaBeSt</em> studied and reviewed methodological approaches to this weighting and comparison problem with special emphasis on multi criteria analysis (MCA) and multi criteria decision analysis (MCDA).</p><p>Key requirement for safe geological disposal of nuclear waste is barrier integrity. The project <em>PeTroS</em> experimentally studied potential percolation mechanisms of fluids within rock salt at isotropic conditions at disposal relevant pressures and temperatures.</p>


2021 ◽  
Vol 1 ◽  
pp. 259-260
Author(s):  
Matthias Englert ◽  
Simone Mohr ◽  
Saleem Chaudry ◽  
Stephan Kurth

Abstract. Are alternatives to the disposal of high-level radioactive waste in a geology repository conceivable? We present the results of the first phase of a research project on the state of the art in science and technology for alternative disposal options. The project is financed by the Federal Office for the Safety of Nuclear Waste Management. Most recently, in 2015, the German Commission on the Storage of High-Level Radioactive Waste (Endlagerkommission) evaluated possible disposal technologies and classified them as either promising, conceivable, or to be pursued further. Only final disposal in a geological repository was considered promising. Conceivable, but not immediately available or not advantageous, were storage in deep boreholes (DBs), long-term interim storage (LTIS), and partitioning and transmutation (P&T). All other alternative disposal options by burial, dilution, or removal from the planet were determined not to be worth pursuing. The Disposal Commission did conclude that none of the three conceivable methods (DBs, LTIS, P&T) would result in earlier disposal of high-level radioactive waste than the preferred final disposal in a mine. However, it recommended continued tracking and regular monitoring of the future development of alternative disposal options, e.g., disposal in deep boreholes. Finally, in 2017, with the amended Site Selection Act, the federal government specified disposal in a repository mine with the option of retrieval during operation or recovery for 500 years after closure. In a learning site selection process, the Federal Office for the Safety of Nuclear Waste Disposal (BASE) reviews the proposals of the project managing company, the Federal Company for Radioactive Waste Disposal (BGE), and prepares a reasoned recommendation to the federal government for a site with the best possible safety. Part of the reasoned recommendation is, among other things, a discussion of alternative disposal options to final disposal in deep geological formations. In the presentation, we report on the status of international research on alternative disposal options, discuss advantages and disadvantages of the technologies, and evaluate the potential of the technologies for the disposal of high-level radioactive waste in Germany. The LTIS is designed as dry storage in a building to be constructed above ground or near the surface and is expected to last for a period of several hundred years. With LTIS it would be possible to gain time for the development of a suitable final disposal option; however, this also postpones the disposal issue indefinitely into the future with undetermined methods. DB storage would involve sinking the storage containers into boreholes with depths of up to 5000 m. This could reduce the expense and be particularly advantageous for smaller inventories, although the potential for the use of engineered barriers would be limited and retrievability precluded according to the current state of the art in science and technology. P&T is primarily intended to separate long-lived transuranic elements from high-level radioactive waste and then convert them to short-lived fission products by neutron irradiation in reactors. The main goal is to reduce the necessary containment times in the repository by changing the inventory, but the effort to treat the waste would be significant and a repository for high-level nuclear waste is still needed. More exotic ideas for alternative disposal include deep geological injection of liquid waste, waste forms that melt themselves into rock, storage inside the ocean floor or subduction zones, shipment to space, burial in ice sheets, or dilution in the atmosphere and oceans. None of these exotic options is currently being actively pursued.


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