Epsilon Open Archive

The three active nuclear power plants in Sweden are Forsmark (Uppsala County), Oskarshamn (Kalmar County) and Ringhals (Halland County). The reactors of these plants are cooled by a maximum of 415 m 3 cooling water per second in total. This cooling water is taken from and is returned to adjacent coastal ecosystems. In the plants' sieving stations, which remove unwanted matter from the inflowing water, substantial amounts of fish are impinged. Fish loss from nuclear power and its effectson surrounding fish populations have been studied continuously during the past decades. Annual reports on the status of adjacent fish populations are published for each Swedish nuclear power plant. In addition, other assignment studies have beenmade. This report compiles earlier knowledge on fish loss effects on fish populations at nuclear power plants. In addition, some new analyses have been made. This compilation shows that:

- Shutting down the Barsebäck Nuclear Power Plant in 2005 has not changedthe increasing long-term trend in catch per unit effort in adjacent waters.

- Trends and trend changes in fish populations as a whole have not in any casebeen possible to trace from losses in sieving stations of the nuclear powerplants, although such effects cannot be excluded.

- Approximately 32-310 tonnes of adult fish are impinged annually in sieving stations of Swedish nuclear power plants.

- This fish biomass is considerably smaller than the loss caused by great cormorant, grey seal, leisure fishing or commercial fishing.

- Considerably more fish roe, larvae and fry than adult fish are affected by the cooling water intakes. This in turn affects recruitment to adult fish stocks.The size of this damage can hardly be calculated in absolute numbers withoututterly uncertain assumptions. However, calculations which have hitherto been made have shown that the loss is minor compared to the size of the stocks in question.

- At the Ringhals Power Plant there is an indoor pool and a large tube connecting sieving stations to the sea, allowing fish passage. Eel has turned out to have a particularly high survival rate (86%) compared to other fish species at the sieving stations of Ringhals. If a corresponding construction would be built at Forsmark, more than 1,000 eels could survive passage to the Bothnian Sea annually. The annual number of eels which could survive at the sieving station of the Oskarshamn plant has not been estimated in this report.

- Effects on the population level are most probable in local populations with asmall geographic distribution in the immediate vicinity of a power plant.

- Suggestions of such fish populations for further studies are the shorthorn sculpin and subpopulations of cod, all of which are in the vicinity of the Ringhals Nuclear Power Plant.