GEA standby cooling towers for the Loviisa nuclear power plant in Finland
21. 04. 2015 In February of this year, installation was completed of the new reserve cooling towers for the Finnish nuclear power plant Loviisa on the island of Hästholmen. The cooling towers were built by GEA EGI Contracting/Engineering Co. Ltd., a member of the GEA Heat Exchangers Group, and were erected under the supervision of Fortum, the customer and plant operator.
The standby cooling towers complement the main cooling system for the two 496-MW reactors. If the main, sea water cooling systems become completely unavailable in the improbable extreme conditions – for example, if an oil slick occurs in the plant vicinity – the standby towers will remove the residual heat from the plant into the air and allow the plant to be safely shut down. The plant operator Fortum, who had already prepared plans for a standby cooling system, implemented these plans following post-Fukushima stress tests. Power plant units Loviisa 1 and 2 went online in 1977 and 1980, respectively. The present schedule calls for Unit 1 to operate until 2027 and Unit 2, until 2030. Both facilities are based on Russian reactor types and were initially designed in accordance with Western safety regulations. These stipulations also included design of redundant emergency cooling systems. After the Fukushima disaster and the following stress tests for European nuclear power plants, Fortum decided in 2013 to contract an additional air-cooled system to even further enhance plant safety. GEA EGI implemented the concept within a few months. Installations started in the autumn of 2014; the new cooling towers were installed on buildings such as reserve residual heat removal system and tank areas, and were integrated into the cooling circuits during the following winter months. Some supplementary works outside the towers itself will be done in spring. During the next regularly scheduled shutdown of the power plant, in autumn of this year, a test of the performance of the standby cooling system will take place. GEA EGI supported the construction work on site, which was performed locally by companies contracted by Fortum. Two cooling towers were provided for each unit of the power plant. The towers were designed to withstand earthquakes and are protected from the weather by panels when not in use. An electric heating system prevents freezing of the towers. One tower in each of the units serves to remove the residual heat from the reactor, and the other tower provides cooling of safety-related systems such as the spent fuel pool cooling, emergency core cooling and containment heat removal systems. The coolers, consisting of integrated finned-tube heat exchangers installed in “A”-form, allow for a small footprint and fast dissipation of heat. The cooling effect is forced by fans powered from the normal grid or by emergency standby diesel generator. The output of the new cooling towers is dimensioned to bring the reactor to hot shutdown state within a few days and later on to cold shutdown state. Fuel pools can be kept in normal operational parameters.
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