Sweden currently has three nuclear power plants with a total of ten reactors.
Forsmark 1 (1980), Forsmark 2 (1981) and Forsmark 3 (1985).
Oskarshamn 1 (1972), Oskarshamn 2 (1975) and Oskarshamn 3 (1985).
Ringhals 1 (1976), Ringhals 2 (1975), Ringhals 3 (1981), Ringhals 4 (1983).
In 1991, the seven-grade international INES scale was introduced for rating of serious incidents and accidents at nuclear power plants.
The worst Swedish incident involving nuclear energy was classified as a third on that scale. It occurred in December 2001, when sharp increases in radiation levels were measured in a shipment from the Swedish nuclear technology and services provider Studsvik AB to the United States.
Eight incidents have been classified as twos, the latest in Forsmark in July 2006 was among the most serious: Two backup generators at Forsmark 1 did not start when a short circuit in a switch-yard outside the reactor building knocked out the electricity supply. The electricity to the control room and the safety system lapsed.
May 1999: Barsebäck 2 was closed when the water cooling was removed because of an wrongful manoeuvre.
September 1997: A valve malfunction at Ringhals 4 was detected only after 19 hours.
November 1996: Oskarshamn 2 started without the sprinkler system in operation.
October 1995: One person at the Studsvik research reactor in Uppsala, north of Stockholm, was overexposed to radiation.
October 1994: Safety valves for a generator at Ringhals 2 did not work.
July 1992: The filters for emergency cooling at Barseback 2 was clogged by mineral wool.
November 1987: Staff at Oskarshamn 3 test-drove a reactor without having activated the reactor scram system.
In addition, there has been a series of incidents assessed as number one on the INES scale.
A fourth Swedish nuclear power plant, Barsebäck (1975), was closed down in 2005, following a government decision.
In 2009, the government announced an agreement allowing for the replacement of existing reactors, effectively ending the earlier phase-out policy.
Sources: News agency TT, Swedish Radiation Safety Authority, World Nuclear Association