753 Technical project description

3.13.2 Transportation to final disposal

After intermediate storage, the spent fuel will be trans- ported to the final disposal facility. For transportation, the fuel will be transferred into a transport container.

Transport containers are commercially available. Dry interim storage containers of the same type as those described above may be used as transport containers. The purpose of the container is to protect the fuel from dam- age during transportation and to protect the surround- ings from the fuel. The transport containers are designed to withstand an airplane crash as well as a kerosene fire. The containers must pass several different drop tests in order to be approved for use in transportation of spent fuel. Furthermore, the transport containers must also remain leaktight under pressure. The thick walls of the transport container, which are made of dense material, effectively attenuate the gamma radiation emitted by the nuclear fuel and completely stop the alpha and beta radi- ation. In normal transportation situations, the dose rate of the radiation shall not exceed 0.1 mSv/h measured at the distance of 1 meter from the outer surface of the trans- port container or 2 mSv/h measured at the outer surface of the transport container. The container and its contents shall withstand the stresses caused by the transportation without damage, and leakage from the container shall remain very small.

Transport containers manufactured in accordance with the guidance values of the International Atomic Energy Agency (IAEA) shall not break even in the case of a high-ve- locity collision with a point-like object, e.g. a reinforced steel column. In such a case, the container may bend and lose its leaktightness. However, as the container would not break, only gaseous or otherwise easily released radioactive substances could escape from the nuclear fuel rods into the environment. As the transportation is carried out at low speeds, the swerving off the road of the transportation vehi- cle and its collision into a concrete structure or a rock cut- ting alone cannot generate forces of this magnitude.

Spent fuel can be transported from the nuclear power plant to the repository by road, by rail, or by sea. In road transportation, a special carriage hauled by a truck is uti- lized. Road transportation will take place under supervi- sion, and each transport will be escorted by supervision and security personnel. In urban areas, police patrols will close off the crossing streets as the transportation convoy passes the area. Taking into account the required stops, the average speed of the transportation convoy will be approx- imately 35 km/h. In rail transportation, the train carrying nuclear fuel must not meet train carriages carrying hazard- ous substances, the grade crossings must be guarded, and the speed of the train must not exceed 40 km/h. Sea trans- portation of spent nuclear fuel requires a vessel specifically designed for the transportation of high level nuclear mate- rial (an example of such vessel being the Swedish “Sigyn”). The dock basin and wharf planned at the western shore of the Hanhikivi headland are dimensioned so that spent nuclear fuel can be transferred into a vessel in that location for sea transport.

In all transportation alternatives, the transportation of spent nuclear fuel from the Pyhäjoki power plant located in the Hanhikivi headland begins as road transportation. An exception to this is the alternative in which sea transpor- tation begins right at the plant’s harbor. In the road trans- portation alternative, the transportation convoy starts at the nuclear power plant and progress to main road 8 via the planned new road. From the crossing of the new road lead- ing to the Hanhikivi headland and main road 8, the spent nuclear fuel transport convoy progresses towards the final disposal facility.

In the rail transportation alternative, the spent nuclear fuel is first transported by road from the nuclear power plant to the Raahe harbor via the following route: the nuclear power plant - the planned road from the Hanhikivi headland to main road 8 - main road 8 northwards - Kok- saamontie - the Raahe harbor railroad stop. The transporta- tion distance is approximately 27 kilometers. At the Raahe railroad stop, the transport container is transferred to a low loader wagon designed for heavy special transport. From the Raahe railroad stop, the rail transportation convoy pro- gresses towards the repository site, where the transport con- tainer is transferred by road from the nearest rail transport offloading location to the repository site.

In the sea transportation alternative, the spent nuclear fuel is transported to the Raahe harbor via the same route as in rail transportation. In the harbor, the transport con- tainer is transferred into a vessel designed for the trans- portation of nuclear materials. From the Raahe harbor, the vessel progresses towards the repository site, where the transport container is transferred by road to the repository site. Alternatively, the harbor planned to be constructed at the Hanhikivi headland can be used.

As the estimated amount of spent uranium nuclear fuel generated over the 60-year service life of the power plant is 1,200–1,800 tons, a total of 120–180 spent fuel transportation operations will be required during the final disposal activ- ities (assuming that one transport container holds approxi- mately 10 tons of spent fuel).

Fennovoima will present the detailed spent fuel transpor- tation alternatives and the associated risk estimates in con- junction with the final disposal facility licensing procedures.

The transportation of spent fuel is subject to license. The licensee must prepare a transportation plan, on the basis of which the Radiation and Nuclear Safety Authority (STUK) will decide on the granting of the transportation license. STUK will assess matters such as the transportation plan, the structure of the transport container, the qualifications of the transportation personnel, and the accident and mali- cious damage preparedness plans.

The radiation and environmental impacts caused by the transportation operations are described in Chapter 7.

3.13.3 Final disposal solutions

According to the Finnish Nuclear Energy Act, all nuclear fuel spent in Finland must be processed in Finland. As there are no spent nuclear fuel reprocessing plants in Fin- land, the reprocessing of spent nuclear fuel is not possible.

76 3 Technical project description According to the Nuclear Energy Agency (NEA), an

OECD organization, geological final disposal is the most recommendable nuclear waste management strategy. In Fin- land, the development of geological final disposal has con- tinued without interruption for some 30 years. As a conse- quence of this long-term development work, Posiva applied for a construction license for a final disposal facility in 2012. The current understanding is that the spent fuel generated in Fennovoima’s nuclear power plant will be disposed of in the Finnish bedrock. The disposal would utilize the KBS-3 (Kärn Bränsle Säkerhet) technology developed in Sweden (SKB Svensk Kärnbränslehantering AB) and Finland (Posiva). As the disposal of spent fuel will not begin until the 2070s, the tech- nological developments in the field can be taken into account in the planning of Fennovoima’s final disposal operations.

In the final disposal solution following the KBS-3 con- cept, the spent fuel is encapsulated in copper canisters, surrounded with bentonite clay, and deposited in deposit holes drilled deep in the bedrock (Figure 3-16). Bentonite is capable of absorbing large quantities of water and conse- quently expand up to ten-fold in favorable circumstances. The expanded bentonite fills tightly the space surrounding the copper canister. Following the end of the disposal oper- ations, the deposit tunnels will be filled with a mixture of bentonite and crushed rock.

The location depth of the repository will be determined by the geological properties of the selected final disposal site. In any case, the final disposal will take place at the depth of several hundreds of meters. While the selection of the final disposal site depends on several different factors, the most significant ones in terms of the safety of the dis- posal are related to the geological properties of the bedrock. Guaranteeing the functionality of the copper canister and the buffer material requires that the bedrock is geologically

stable, the groundwater flow is low, and the chemical prop- erties of the groundwater are favorable.

In addition to the deposit tunnels, the final disposal facility will comprise an encapsulation plant and the associ- ated auxiliary facilities.

Fennovoima is currently preparing an overall plan on the final disposal of spent nuclear fuel. The matters dis- cussed in the plan include the preliminary schedule for the disposal of the spent nuclear fuel generated in Fenno- voima’s nuclear power plant and interests in common with the current operators regarding their final disposal project. One of the main goals of the overall plan is to determine an optimal final disposal solution which can, for its part, promote cooperation between Fennovoima and the other parties under the nuclear waste management obligation.

A condition attached to Fennovoima’s Decision-in-Prin- ciple states that Fennovoima shall produce an agreement on nuclear waste management cooperation with the parties currently under the nuclear waste management obligation or start its own EIA procedure for the final disposal project by summer 2016. The final disposal of Fennovoima’s spent fuel will require the completion of EIA and Decision-in-Princi- ple procedures as well as construction and operating licenses regardless of the location of the final disposal facility.

3.14 Decommissioning of the

power plant

The minimum estimated operational lifetime of the nuclear power plant is 60 years. Following the end of its lifetime, the plant will be closed down and dismantled (decommis- sioned). Decommissioning ensures the safety of the plant’s surroundings after it is closed down.

Figure 3-16. Radioactive substance release barriers used in the KBS-3 method.

Overground facilities of the final disposal facility

Underground facilities of the final disposal facility Bentonite clay Bedrock Spent nuclear fuel element Disposal canister Nuclear fuel rod

cladding

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