In the morning the 24th of March Norwegian authorities were informed by Russian authorities and IAEA about an incident at the nuclear power station in Sosnovyj Bor near St. Petersburg. The National Institute of Radiation Hygiene was alarmed together with other Norwegian organizations through the Norwegian Emergency Committee and by Norwegian press media. This report gives a summary of the incident, the release of radioactive substances and of the actions taken by the National Institute of Radiation Hygiene. The incident did not affect the Norwegian territory and will not represent any health risk for Norwegian citizens staying in St. Petersburg under and after the incident. The Norwegian authorities did not advice any restrictions on travelling activities to the St. Petersburg area. 2 refs., 7 figs., 4 tabs.