Safeguards and Security in Nuclear Waste Essay

Geological Repository of Nuclear Spent Fuel

Geological repository of nuclear spent fuel is the nuclear wastes keeping technology popular in the majority of countries around the globe. Its popularity is explained by a relatively high degree of safety it offers and its economic affordability. According to Kollar, a geological repository of nuclear spent fuel should correspond to the following standards: (1) it should be first sited and be placed on a stable platform; (2) it is preferred to locate such storages in an unpopulated area; (3) the area should have no major ground waters; and (4) the depths of tunnels is to be no less than 250 meters (34, 36, 39).

Safeguard designs for geological repositories of nuclear spent fuel have their primary objective to ensure high safety standards for nuclear wastes storage (Kollar 43). The theoretic background for these safeguard designs is based on the fact that properly chosen host-rocks are capable of absorbing radiation and dissipating heat (Okko 5). Besides, an efficient approach to choosing the rock types and depth of bedding will allow an engineer to avoid the problem of radionuclides interaction with the waters. The essential security solutions for a geological repository of nuclear spent fuel include the following: highly trained security force monitoring the perimeter of the storage. “high-quality fenced perimeter”, “bi-static microwave intrusion detection system”, “floodlights and infrared lighting system”, and “Intrusion reporting to a Central Alarm Station” (Kollar 38). Since geological repositories of nuclear spent fuel are built deep underground, there is no technical safeguard requirements need to protect them from human invaders in the same way as above-ground areas storing nuclear agents (Kollar 39). This feature of geological repositories is among their major competitive advantage over other solutions.

Security Designs for Geological Repository of Nuclear Spent Fuel

Security designs for geological repositories of nuclear spent fuel incorporate a number of measures to prevent the reciprocal action between the stored wastes and the surrounding rocks. Since the level of nuclear wastes storage safety depends directly from its depth below the surface, contemporary storage standards require using available mining techniques to drill repositories at the depth of no less than 500 to 900 meters (Kollar 49).

The most common method of geological repositories building amounts to drilling a vertical shaft along with the access tunnels to reach the planned depth (Kollar 34). At the planned depth, further provisions are made to facilitate horizontal disposal galleries for placing SNF and HLW (IAEA 11). At that, the used fuels are put there entombed and then, they are surrounded by the chosen butter materials and backfilled and sealed afterwards (IAEA 18).

To put off the threat of radionuclides migration, storage areas are equipped with multiple barriers (IAEA 11). These berries can be of two types: geological and engineered. Both types of barriers form the multi barrier system (IAEA 18). All these procedures are performed only in the areas with the selected host rocks that match the requirements for storing every particular type of nuclear spent fuels because rocks are the most important isolation barriers (Okko 15). Important characteristics of host rocks are medium, and presence of ground waters (Kollar 52). The engineering shielding system has three elements: the waste matrix, initial package such as fuel rod cladding, and bentonite clay. The final barrier in the multi barrier system is the geological one and it is the rock formation (Okko 5).

Experience of Sweden and Finland in Geological Repository of Nuclear Spent Fuel

Sweden and Finland are the countries with outstanding performance in the area of implementing high safety standards of utilizing geologic repositories of nuclear spent fuel. These countries have over thirty years of experience in the area of elaborating the safety technologies, safety standards, their implementations, and constant upgrading. The countries have both come up with the policy requiring utilizing a once-through fuel cycle and disposing it in dry or wet storage afterwards as the remarkable progress in the given area (Kollar 39).

Sweden and Finland are partners in the area of nuclear waste disposal. They work together to develop the same strategy of spent fuel conservation and have already achieved outstanding results (Okko and Hack 5). Currently, both Sweden and Finland use cast iron enforced copper canisters to encapsulate the used fuel. In Sweden, there is no specific regulation requiring using only one repository site (Kollar 39). In Finland, there are adopted regulations controlling that the used fuels are stored in the only repository site.

Finland has also made notable progress in development of technologies for the storage of nuclear wastes. According to Okko and Hack, the Finnish history of nuclear spent fuels disposal is quite long as it can be seen from the following quotation, “the development of the geological repository was decided in 1983 and consequently R&D work to develop methods to carry out new type of site investigations to locate solid bedrock suitable for disposal was initiated” (7). The country never stops to upgrade its nuclear spent fuels keeping technologies.

Comparison between Near-Surface and Deep Boreholes Geological Repository

Compare and contrast analysis of strengths and weaknesses of near-surface and deep boreholes geological repositories suggests that the last technology is much safer in terms of nuclear wastes storage. This conclusion can be supported judging by the fact that deep borehole disposal allows complete assurance of all major safety standards when it comes to dealing with SNF and HLW (Okko 15). Deep borehole geological repositories are also preferred for the countries that have few SNF and HLW. This technological solution is also considered superior to near-surface repository since they provide a mechanism to dispose no retrievable wastes (Okko 15). In addition, deep boreholes geological repositories allow achieving the higher degree of natural separation from the environment and biosphere. Moreover, the safety rates provided by the deep boreholes technology is considerably higher due to the fact that at the depth of over 5000 m, there is few to no underground water movement, and therefore, the threat of its interaction with the radionuclides is improbable (Okko 15). Still, the deep boreholes technology has a considerable disadvantage over the near-surface depositary, which is the economic side of the issue (JRC 24).

Analysis of Benefits and Challenges

The security challenges connected with the problem of storing nuclear wastes in repository sites are (1) the presence of gases, water, and brine within the repository site; (2) the response of the repository rock to the temperature influence of the stored fuel; (3) potential threat of radionuclides migration; and (4) the packaging degradation of the waste (Okko and Hack 14). In addition, a notable challenge is increased incidence of geologic events all around the globe including sea-level rise, earthquakes, formation of continental ice sheets, subsidence, and volcanic eruptions (JRC 25).

The benefits of using deep geological repository sites for used nuclear fuel storage are multiple. First of all, the host-rocks feature high degree of capacity to absorb radiation and dissipate high temperature if they are properly chosen (Horvath and Rachlew 38). Besides, the flexibility and broad range of rock types is available (Horvath and Rachlew 38).

Next, storage of used fuels in repository sites features the higher degree of safety from the point of view of the threat of accidental or malicious intrusion than other types of storage technologies (Horvath and Rachlew 38). This type of nuclear spent fuels storage ensures full prevention from interference into human economic activity (IAEA 13). Next, repository sites are highly adaptive for constructing barriers minimizing the radionuclides migration (IAEA 15). They require minimal to no maintenance. Construction of repositories is feasible from an engineering viewpoint (IAEA 9).

Based on the rationale provided above, it is reasonable to conclude that the deep geological repositories usage is the optimal solution for storing nuclear spent fuels all over the world. This technologic solution offers both the most advantageous safety standards for keeping this hazardous type of wastes and is available for usage even in the economically-disadvantaged courtiers because its economic benefits exceed its costs considerably. Moreover, this type of nuclear waste deposits features the high degree of safety from terrorist attacks or other adversaries since the storage area is located at a depth not available for common people. The example of advanced countries in the area of geologic repositories usage such as Sweden and Finland is another proof of effectiveness of this technology.

Works Cited

Horvath, Akos, and Elisabeth Rachlew. “Nuclear Power in the 21st Century: Challenges and Possibilities.” Ambio 45.1 (2016): 38-49. Print.

IAEA. “Technological Implications Of International Safeguards For Geological Disposal Of Spent Fuel And Radioactive Waste.” IAEA Nuclear Energy Series, (2010): 1-29. Print.

JRC. “Management of Spent Nuclear Fuel and Its Waste.” EASAC Policy Report 23 (2014): 1-37. Print.

Kollar, Lenka. Proliferation Resistance Assessment Of Various Methods Of Spent Nuclear Fuel Storage And Disposal. Dissertation. Purdue University West Lafayette, 2012. Print.

Okko, Olli and Tapani Hack. “Developing Safeguards for Final Disposal of Spent Nuclear Fuel in Finland.” (2014): 1-16. Print.

Okko, Olli. “Safeguards for Final Disposal of Spent Nuclear Fuel.” (2003): 3-17. Print.