593 Technical project description

3.6.2 Civil engineering work

3.6.2.1 Water structures

Figure 3-5 shows the planned locations of the water struc- tures required for the power plant. The dock basin, the nav- igation channel, the auxiliary cooling water inlet channel, and the cooling water intake structures will be located in the western and north-western parts of the Hanhikivi head- land. The cooling water discharge structures will be located on the northern shoreline.

The building of the navigation channel and dock basin on the western shoreline of the Hanhikivi headland is required to enable sea traffic serving the nuclear power plant. The sea link will be needed for transporting machin- ery and equipment during the construction of the power plant and annual maintenance outages and, later in the future, for operations such as possible transporting spent nuclear fuel. Furthermore, the navigation channel and the dock basin will function as part of the plant’s cooling water intake structures.

The water depth of the planned dock basin is 10 meters, and the length of the turning basin will be 200 meters. A wharf with an approximate length of 120 meters will be located in the southern part of the dock basin. According to preliminary plans, the tops of the breakwaters delimiting the dock basin will be at the height of 4 meters from the sea surface, and the combined total length of the breakwaters will be some 650 meters. The auxiliary cooling water inlet channel starting at the southern end of the breakwater will be 700 meters long, with a bed width of 40 meters and a depth of six meters. The navigation channel will be 2.4 kilo- meters long, with a safe clearance depth of 8.1 meters and a bed width of 80 meters.

The power plant cooling water will be taken in at the eastern edge of the dock basin and led to the power plant through an approximately 200-meter long rock tunnel. The cross-sectional area of the tunnel will be approximately

40–45 m2_{. Phenomena impeding the intake of cooling}

water, such as the impact of algae, sand, subcooled water, and potential pack ice, have been taken into account in the determination and positioning of the cooling water intake location. The intake structure will be dimensioned so that the flow at the mouth of the intake opening remains low (at approximately 0.2–0.3 m/sec.). This will minimize the amount of solids carried along by the cooling water.

The mouth of the cooling water tunnel will be protected with a 15–17-meter-wide concrete structure which will be equipped with a coarse screen in order to remove coarse solids from the cooling water. The building of the concrete structure will take place in conjunction with the perfor- mance of the hydraulic engineering works. The building site will be protected by a cofferdam. During the opera- tion of the power plant, the concrete structure will remain mostly submerged. A wharf-like concrete structure will be visible above the water.

The warmed-up cooling water will be led from the power plant through an approximately 300-meter-long tun- nel to the northern shore of the Hanhikivi headland for dis- charge in the sea area. Cooling water discharge structures, including a concrete discharge structure, a discharge chan- nel, and banks protecting the upstream part of the channel, will be built in conjunction with the performance of the hydraulic engineering works. The length of the discharge channel to be dredged will be 600 meters, with a depth of −3 meters and an approximate bed width of 70 meters. The western and eastern banks protecting the upstream part of

Figure 3-5. The planned locations of the navigation channel, harbor area, cooling water intake struc- tures, auxiliary cooling water intake channel, and cooling water discharge structures in the Hanhikivi headland. The discharge structure area is outlined in red, and other structures are outlined blue. Cooling water

discharge structures

Disposal areas for suction-dredged masses

Disposal area for other dredging masses Auxiliary cooling water inlet channel

Harbor area and cooling water intake structures Navigation channel

60 3 Technical project description

the discharge channel and the discharge structure will be 200 meters and 150 meters long, respectively.

3.6.2.2 Earth-moving work

Earth-moving work produces large amounts of soil and rock excavation and dredging masses. The main contribu- tors to the total mass amount will be the dock basin and navigation channel dredging masses and the plant area soil and rock excavation masses. The rock material generated during the earth-moving work will be utilized, as far as possible, in the various filling and leveling operations per- formed in the plant area, as well as in the building of break- waters in the harbor and cooling water discharge areas. As the ground elevation in the Hanhikivi headland is low, the ground will be raised to 4.5 meters above the sea level in the nuclear power plant building area. It may also be neces- sary to transport additional rock material onto the site for plant area filling operations.

The loose soil dredged up in the course of the hydraulic engineering work will also be utilized, as far as possible, in the plant area filling operations. The masses that are unsuitable for filling operations, such as masses contain- ing clay, would be dumped at a separate marine spoil area. The planned marine spoil area is located approximately 9.5 to the west from the Hanhikivi headland, and its area is some 190 hectares.

The estimated 100,000–150,000 m3 _{(bulk volume) of top-}

soil removed from the headland area generally cannot be uti- lized in the plant area, and it will be transported to separately agreed spoil areas on land.Table 3-2 shows an estimate of the quantities of the generated masses and their utilization.

3.6.3 Construction site safety and security,

workforce management and environmental

management

The management of construction site safety and environ- mental matters will be planned, and instructions drawn up, before the start of the construction work, and the process will be continued as the construction work progresses. The planning will be based on the safety and environmental risks identified for the operations and each work phase, and it will aim to eliminate the risks in advance. Fennovoima and the plant supplier will appoint separate organizations

for the management of safety and environmental risks and the controlling of day-to-day activities. These organizations will also be assigned with the responsibility for cooperating with the various authorities and the representatives of the regional rescue department.

Induction training will be organized to introduce the workers to the safety, security and environmental require- ments pertaining to the nuclear power plant project and the worksite, as well as the special characteristics of the worksite, before they begin work at the site. Additional training will be implemented during the various work phases as needed. Care will be taken to ensure that the workers receive the necessary training and instructions in a language that they understand.

3.6.3.1 Occupational safety

In accordance with the Government Decree on the Safety of Construction Work (205/2009), Fennovoima will ensure that the construction work is planned and implemented safely and without causing harm to the health of the work- ers. The “zero accidents” principle is implemented at the worksite. According to the principle, occupational injuries and accidents can be prevented by careful planning and implementation of work and work phases. The planning will be based on the safety risks identified for each work phase, and it will aim to eliminate the risks in advance.

Fennovoima will be responsible for preparing the safety document for the planning and preparation of the construc- tion operations. The document should present the potential hazards arising from the characteristics, circumstances, and nature of the project, as well as occupational safety-related information associated with the implementation of the project. Furthermore, Fennovoima will prepare the general safety rules and instructions for the worksite, which are to be observed by everyone working at the site.

The worksite will be assigned a main contractor whose responsibility is to prepare the actual safety and worksite plans and safety instructions, organize the associated train- ing, and introduce the plans and instructions into use. The safety plan will show the way in which the construction work is going to be implemented safely, either through elimination of the potential hazards and detriments or through management of the associated health and safety risks. The safety plan will introduce the general occupa-

Masses generated during construction Quality (bulk

volume in m3₎

Removed topsoil 110,000

Plant area soil and rock excavation masses 300,000 Cooling water tunnel rock excavation masses 60,000 Navigation channel dredging and rock excavation masses 380,000 Dock basin and cooling water intake structure dredging and soil/rock

excavation masses 750,000

Auxiliary cooling water intake channel dredging and rock excavation

masses 110,000

Cooling water discharge structure dredging and soil/rock excavation

masses 140,000

Table 3-2. Estimated quantities of masses generated during the nuclear power plant construction work.

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