Our environment 2020

The annual collective radiation dose of the Loviisa power plant’s own personnel and external contractors in 2020 was the lowest in the plant’s operating history. This shows that long-term work in radiation safety produces good results.

Emissions of radioactive effluents into the environment in 2020 were, as in previous years, significantly lower than the limits set for nuclear power plant emissions.

Based on emissions and meteorological data, the estimated radiation dose to the surrounding population was about 0.2% of the set dose limit. The radiation dose to the surrounding population from radioactive substances originating from the Loviisa power plant accounted for only a minor increase compared to the radioactive dose from other sources (like, e.g., radon and medicine).

The radiation monitoring programme carried out in the power plant surroundings occasionally detected radionuclides originating from the plant, but the concentrations detected were very small.

Waste management at the Loviisa power plant is comprised of two separate areas: waste management for the non-controlled area and waste management for the controlled area. All waste generated in the controlled area is treated as radioactive. Waste generated outside the controlled area can be treated as waste from a conventional industrial plant.

The goal of conventional waste management is to prevent the production of waste and to reduce the amount of landfill waste through effective sorting. In 2020 about 1 296 tonnes of waste was transported from the power plant area. Of this, 158 tonnes was landfilled, 961 tonnes was reused as materials or energy, and 177 tonnes was treated as hazardous waste.

Waste generated in the controlled area is divided into three categories: Low-level waste (maintenance waste), intermediate-level waste (liquid waste), and high-level waste (spent fuel). Maintenance waste is either cleared as non-active and treated as conventional waste or disposed of in the final repository located at a depth of 110 metres in the power plant area. Also the solidified liquid waste was disposed of in the final repository.

Thanks to efficient sorting and packaging, the amount of maintenance waste for final disposal in 2020 accounted for a small share. Liquid waste is purified and released into the sea or stored and solidified in concrete and then disposed of in the final repository. Spent fuel is stored to await final disposal in Eurajoki.

The power plant’s most significant environmental impact is the thermal load on the sea caused by the cooling water, which heats up by about 10 degrees as it passes through the plant. In practice, two-thirds of the thermal energy produced by the reactor ends up in the sea with the cooling water. According to temperature measurements, the discharged water raises the temperature of the sea water during the growing season by about 1-2.5 degrees within a 1-2 kilometre range from the discharge point.

The cooling water discharge area remains unfrozen throughout the winter. The size of the open water and thin ice area depends on winter temperatures. In 2020, the power plant used a total of about 1,328 million m3 of sea water for cooling, and the thermal load on the sea totalled 54,586 terajoules.

In accordance with the environmental permit, the amount of cooling water released into the sea should not exceed 1,800 million m3 per year or 56 m3/s. The cooling water’s thermal load on the sea may not exceed 60,000 terajoules annually. The limits set by the permit were not exceeded in 2020.

The process and domestic water required by the power plant is sourced from Lake Lappominjärvi, which is located about 5 kilometres north of the power plant.

The water is purified before use at the water plant, and the water used as process water is additionally treated at the demineralisation plant. The total volume of water withdrawn from Lake Lappominjärvi in 2020 was about 155,040 m3.

According to the service water withdrawal permit, the power plant can withdraw up to 180 m3/h of water from the lake for a short period of time and a maximum of 150 m3/h per quarter.

The domestic wastewater generated is treated at the power plant area’s biological-chemical wastewater treatment plant, to which about 19,443 m3 of wastewater was piped in 2020.

In accordance with the environmental permit, domestic wastewater must be treated so that the biological oxygen demand (BOD7ATU) of wastewater discharged into the sea does not exceed 15 mg/l and the total phosphorus concentration does not exceed 0.7 mg/l, calculated as annual averages. The efficiency of the treatment process must be at least 90% for both variables.

According to the monitoring results, the treatment plant reached results compliant with the conditions of the permit: the biological oxygen demand of treated wastewater in 2020 was 3.1 mg/l on average and total phosphorus concentration 0.16 mg/l. The load caused by domestic wastewater in 2020 was 3.1 kg of phosphorus, 932 kg of nitrogen and 180 kg of solids.

The environmental permit of the power plant does not set any limits for the process wastewater load. However, the nutrient load caused by the process wastewater is monitored through samples taken in accordance with the monitoring programme.

The load caused by process wastewater in 2020 was 2.3 kg of phosphorus, 929 kg of nitrogen and 74 kg of solids. The power plant’s share of the total load in the Hästholmen sea area in 2020 was about 0.7% phosphorus and about 4.7% nitrogen.

No permit limits were exceeded at the Loviisa power plant in 2020 nor were there any breaches of permit conditions.

One chemical leak was reported at the Loviisa power plant in 2020. In the commissioning phase of the new storage for concentrated chemicals, concentrated lye (48% NaOH) was being transferred from the chemical storage tank into the new storage tank. Because of an incorrectly closed valve, the lye flowed through the overflow line into a water tank instead of into the storage tank; the lye filled the water tank and, via the pressure relief line, leaked onto the top of the tank and to the floor of the room. About 300 litres of 30% lye ended up on the floor of the room and flowed through the floor drain to the power plant’s cooling water channel, and from there through the cooling water discharge outlet into the sea. Based on the criteria in effect, sodium hydroxide is not classified as hazardous. Before the chemical was discharged into the sea, the chemical was diluted considerably in the plant’s cooling water channel.