Deep geological repository: Wikis

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A deep geological repository is a nuclear waste repository excavated below 300 m within a salt dome or bedrock. It entails a combination of waste form, waste package and engineered seals that is designed to provide a high level of long-term storage without future maintenance.

Contents

Principles and background

Common elements of potential repository systems include the radioactive waste, the containers enclosing the waste, the tunnels housing the containers, and the geologic makeup of the surrounding area.

With deep ocean disposal in stable clay in the seabed being excluded for legal and political reasons, there is a strong consensus among all major countries that the deep geological repository is the only possible permanent solution, and this is being studied extensively. Many detailed studies, including laboratory tests, exploratory boreholes, and the construction and operation of underground research laboratories where large-scale in-situ tests are being conducted. For example, currently underground research is done on claystone by the Mont Terri Rock Laboratory in Switzerland.[1] Some countries are developing their own repository systems, others are working in collaboration with other nations to develop common technologies and possibly future shared facilities.

Storage sites

Land Name of the repository / Region Geology Depth Phase Laboratory In service
Argentina Sierra del Medio (Gastre) granite[2] Not started under discussion no projected date no projected date
Canada Repository Kincardine, Ontario Not started under discussion [3] after 2034[4]
China Not started under discussion 2020 2050
Finland Olkiluoto[5]. bedrock 500 m under construction 2020
France Meuse/Haute Marne Underground Research Laboratory[6] mudstone 500 m lab research 2000 2025
Germany Schacht Asse II salt dome 750 m Closed 1995 - - - - - - - -
Germany Repository for radioactive waste Morsleben salt dome 630 m Closed 1998 - - - - - - - -
Germany Salt dome Gorleben salt dome under discussion no projected date no projected date
Germany Schacht Konrad 800 m under construction 2013
United Kingdom Not started under discussion no projected date no projected date
Japan Horonobe, Hokkaidō sedimentary rock[7] Not started under discussion 2023-2027 2040
Sweden Östhammar Municipality bedrock Not started Decided[8] no projected date no projected date
USA Waste Isolation Pilot Plant salt dome 655 m in production 1999
USA Yucca Mountain nuclear waste repository ignimbrite ?? under discussion 2020

In addition Belgium, Russia and Spain support deep geological disposal as the best method for isolating highly radioactive, long-lived waste[9].

Safety and feasibility assessment

The pit Asse II is a former salt mine in the mountain range of Asse in Lower Saxony/Germany, that was allegedly used as a research mine since 1965. Between 1967 and 1978 radioactive waste was placed in storage. Research indicated that brine contaminated with radioactive caesium-137, plutonium and strontium was leaking from the mine since 1988 but was not reported until June 2008[10]

The repository for radioactive waste Morsleben is a deep geological repository for radioactive waste in the rock salt mine Bartensleben in Morsleben, in Lower Saxony/Germany that was used from 1972–1998. Since 2003 480,000 m3 (630,000 cu yd) of salt-concrete has been pumped into the pit to temporarily stabilize the upper levels. The salt dome is in the state of collapse.

The Waste Isolation Pilot Plant (WIPP) in the United States went into service in 1999 by putting the first cubic metres of transuranic radioactive waste[11] in a deep layer of salt near Carlsbad, New Mexico.

Future plans and remaining risks

Schematic of a geologic repository under construction at Olkiluoto Nuclear Power Plant site, Finland
Swedish KBS-3 capsule for nuclear waste.

The ability of natural geologic barriers to isolate radioactive waste is demonstrated by the natural nuclear fission reactors at Oklo, Africa. During their long reaction period about 5.4 tonnes of fission products as well as 1.5 tonnes of plutonium together with other transuranic elements were generated in the uranium ore body. This plutonium and the other transuranics remained immobile until the present day, a span of almost 2 billion years.[12] This is quite remarkable in view of the fact that ground water had ready access to the deposits and they were not in a chemically inert form, such as glass. There is also a proposal for an international high level waste repository in Australia[13] and Russia[14]. However, since the proposal for a global repository in Australia (which has never produced nuclear power, and has one research reactor) was raised, domestic political objections have been loud and sustained, making such a facility in Australia unlikely.

In 1978 The U.S. Department of Energy began studying Yucca Mountain, within the secure boundaries of the Nevada Test Site in Nye County, Nevada, to determine whether it would be suitable for a long-term geologic repository for spent nuclear fuel and high-level radioactive waste. This project faced significant opposition and suffered delays due to litigation by The Agency for Nuclear Projects for the State of Nevada (Nuclear Waste Project Office) and others.[15] The Obama Administration rejected use of the site in the 2009 United States Federal Budget proposal, which eliminated all funding except that needed to answer inquiries from the Nuclear Regulatory Commission, "while the Administration devises a new strategy toward nuclear waste disposal."[16] On March 5, 2009, Energy Secretary Steven Chu told a Senate hearing the Yucca Mountain site is no longer viewed as an option for storing reactor waste."[17]

The process of selecting appropriate deep final repositories is now under way in several countries with the first expected to be commissioned some time after 2010.[18] Sweden is well advanced with plans for direct disposal of spent fuel, as its Parliament has decided that this is acceptably safe, using the KBS-3 technology. In Germany, there is a political debate about the search for a final repository for radioactive waste, accompanied by loud protests - especially in the Gorleben village in the Wendland area, which was seen ideal for the final repository until 1990 because its location next to the border to the former GDR. This location is currently used for the temporary storage of nuclear waste.

But despite a long-standing agreement among many experts that geological disposal can be safe, technologically feasible and environmentally sound, a large part of the general public in many countries remains skeptical.[19] Major environmental and security problems at existing repositories such as Schacht Asse II in Germany have also cast doubt on the quality and objectivity of such safety assessments [10]. One of the challenges facing the supporters of these efforts is to demonstrate that a repository will contain wastes for so long that any releases that might take place in the future will pose no significant health or environmental risk. Existing repositories in deep geological formations (e.g. Schacht Asse II and the repository for radioactive waste Morsleben in Germany) show that solutions to the problem of radioactive waste remain elusive and that safe and environmentally sound storage cannot be guaranteed, especially over long periods of time.[19]

See also

References

  1. ^ Nagra – Swiss National Cooperative for the Disposal of Radioactive Waste
  2. ^ The Argentine radioactive waste respository: Basic criteria, preliminary siting and design conceptual basis
  3. ^ Ontario Power Generation DGR page
  4. ^ Radioactive waste: an international concern
  5. ^ Posiva. "Underground characterisation facility or ONKALO". http://www.posiva.fi/englanti/tutkimus_esittely.html.  
  6. ^ Andra - French National Radioactive Waste Management Agency
  7. ^ Japan-R&D on Processing and Disposal Technologies for High-Level Radioactive Waste
  8. ^ http://www.skb.se/Templates/Standard____26400.aspx
  9. ^ Radioactive waste: an international concern
  10. ^ a b Problems at Germany's Asse II Nuclear Waste Repository
  11. ^ DOE Waste Isolation Pilot Plant Receives EPA Recertification
  12. ^ R. Naudet. 1976. The Oklos nuclear reactors: 1800 millions years ago. Interdisciplinary Science Reviews, 1(1) p.72-84.
  13. ^ Holland, I. (2002). "Waste not want not? Australia and the politics of high-level nuclear waste". Australian Journal of Political Science (37): 283–301.  
  14. ^ [Disposition of high-level waste and spent nuclear fuel: The continuing societal and technical challenges. Washington, DC: National Academy Press. 2001.]
  15. ^ Earthquakes In The Vicinity Of Yucca Mountain
  16. ^ A New Era of Responsibility, The 2010 Budget, p. 65.
  17. ^ Hebert, H. Josef. 2009. “Nuclear waste won't be going to Nevada's Yucca Mountain, Obama official says.” Chicago Tribune. March 6, 2009, 4. [1] Accessed 3-6-09.
  18. ^ "Final disposal nearing realization". Press release. Swedish Nuclear Fuel and Waste Management Co.. 2007-09-28. http://www.skb.se/FileOrganizer/Pressrum/Pressmeddelanden%202007/Final%20disposal%20nearing%20realization.pdf. Retrieved 2009-01-05.  
  19. ^ a b Vandenbosch, Robert, and Susanne E. Vandenbosch. 2007. Nuclear waste stalemate. Salt Lake City: University of Utah Press.

External links

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