Deep Geological Repository
The history of radioactive waste disposal dates back sixty years. Radioactive waste first began to accumulate during the initial period of the nuclear arms race and increasingly due to the rapid development of nuclear power in the 1960s and 70s. The professional scientific community was, therefore, confronted with the question of how best to store the waste so that it would not adversely affect mankind and the environment. The issue of the disposal of low- and intermediate-level waste was quickly resolved through storage in surface repositories.
However, up until the 1980s, the permanent storage of spent nuclear fuel and high-level waste was not considered an urgent priority. Several reasons existed for the delay in determining an immediate solution, including:
- The amounts of such materials were relatively small.
- The materials can be easily stored under either wet or dry conditions for several decades.
- Due to the high level of radioactivity, such materials must be effectively isolated for long periods of time and require the installation of an efficient protection system, for which it was necessary to start accumulating the requisite financing.
- Spent nuclear fuel can, under certain conditions, be reprocessed and reused in new types of reactors.
Work on determining potential disposal methods was initiated in a number of countries in the early 1970s. Although it was already suspected that the most appropriate disposal option would be to store such materials in deep geological repositories, certain other options were investigated, however, following in-depth analysis, these alternatives proved to be unsuitable. For example, storage in permafrost layers would be faced with uncertainties concerning the future evolution of the Earth’s climate; moreover, placement of the waste at depths of just 5-8km below the Earth’s surface also faced uncertainties concerning possible volcanic activity or shifts in the Earth’s tectonic plates potentially resulting in the waste being transported back to the surface.
In addition, while storage in the sea or beneath the seabed has been considered, the use of seas and oceans for the storage of radioactive waste is subject to a ban (i.e. the London Convention). At the same time, it would be difficult to prove that such waste would not contaminate sea water and aquatic organisms. Storage in Antarctic glaciers was ruled out due to the ban on the export of radioactive waste to Antarctica. Finally, firing such waste into space proved not only to be economically non-viable and unethical, but also dangerous, especially if an accident were to occur during the rocket take-off phase.
Finally, it was concluded that the most appropriate method for the disposal of spent nuclear fuel and high-level and long-lived nuclear waste consisted of its placement in deep rock formations. It was considered that this option would fulfil the various safety, technical feasibility and economic requirements. Safety analysis demonstrated that certain rock formations are able to maintain the integrity of the storage system for hundreds of thousands or even millions of years. The technical resources are already available for the excavation of the access and storage spaces as is the proven technology for the transport and emplacement of nuclear materials in disposal containers. Furthermore, the issue of the long-term financing of the construction and operation of such repositories has been solved, as most countries have already began accumulating the financing for this purpose.