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A nuclear reactor in Finland entered an automatic shutdown after a radiation spike was detected inside the plant’s systems on Thursday, but no radiation escaped the facility.
“This is a significant and an exceptional incident and we consider it important to spread correct information about it,” Finland’s Minister of Social Affairs and Health Aino-Kaisa Pekonen told reporters.
The elevated readings stemmed from a room regularly showing higher values during normal operations, and no power company employees had been exposed to radiation or were injured.
Jarmo Tanhua, CEO of the nuclear power plant operator TVO, said the incident was an unparalleled event in the facility’s history. TVO is a consortium of power and industrial companies.
“There is no danger to people or the environment” from the incident at the Olkiluoto 2 power plant in western Finland, said Tomi Routamo, deputy director at nuclear safety authority STUK.
Although radiation levels around the plant are normal and there was no external leak, STUK described the incident in a tweet as “serious” and said readiness protocols had been launched in conjunction with the plant’s operator, TVO.
STUK later announced: “The situation is stable and the plant is safe,” and radiation levels had returned to normal.
“No such event has happened in Finland before,” Routamo added.
Automatic systems detected raised levels of radioactivity in the steam pipes of the reactor’s cooling system, although the cause of the spike was not yet known and investigations are ongoing, according to Routamo.
A previous water-pipe fault occurred in another Finnish nuclear plant about 30 years ago, but the Olkiluoto incident involves the so-called primary circuit pipes which are closer to the reactor and therefore face higher concentrations of radiation.
The International Atomic Energy Agency (IAEA) said in a statement it had been informed of the incident and was in contact with Finnish authorities.
Plant operator TVO said an automatic reactor shutdown, or “scram”, was triggered at 12:22pm local time (10:22 GMT).
“It was shut down automatically for some reason which we don’t know, and nothing really happened,” TVO spokesman Pasi Tuohimaa. “There’s no harm anywhere.”
The Olkiluoto 2 reactor, which began operations in 1980, will be “driven to a safer state” so investigations can be carried out, Routamo said.
“They have to check that everything is OK and then they have to have our permit from STUK to start the reactor again,” Routamo added.
Finland receives about one-third of its energy from nuclear sources, and two new nuclear reactor construction projects are currently under way in the Nordic country.
The most advanced of them, a third reactor at the Olkiluoto site, is running more than 10 years behind schedule because of hold-ups with the plant’s supplier, the French-led Areva-Siemens consortium.