Wednesday morning 21 May one subcontractor of Oskarshamn Nuclear Power Plant (NPP) was stopped at a security checkpoint. The security staff of the NPP found traces of an explosive substance on a plastic bag carried by a person. This was verified through extra controls with the used control equipment. The police was informed and took the person into custody on suspicion for planning sabotage. Later during the day another person was suspected to be involved with the person carrying the plastic bag that had traces of explosive substances and was also taken into custody. Both were released from custody after about 24 hours. In an early check by the police it was determined that the substance on the plastic bag couldn’t have caused any explosion.
At the time for the event Oskarhamn NPP reactor 2 was down for maintenance during the annual outage. During the day a search for explosives at this plant where started. In the evening of 21 May the management of the Oskarshamn NPP reactor 1 decided to shut down for a corresponding search for explosives. This was a safety precaution to ensure that the plant where free from explosives, since the suspected persons also had access to areas within the reactor. After a couple of days the police completed the search for explosives inside unit 1 and 2 of the Oskarshamn NPP. The result was that nothing had been found that indicate any kind of explosives. The maintenance works at reactor 2 were restarted again. Reactor 1 started after some further days.
Further analyses of the explosives found were performed by The Swedish Laboratory of Forencic Science (SKL). The result from the analyses shows that it was a big probability that the explosives contained Trinitrotoluene (TNT). During investigations they have not been able to establish the true origin of the explosives.
Taken together, the result from the criminal investigation analysis, check of the plants equipment for measurement and the police investigations, there is no longer any suspicion about conscious or unconscious attempt to take in explosives to the NPP. The pre investigation has been closed by the prosecutor and the two persons who earlier were suspected by the police are no longer under any suspicion.
Information has been updated by the Swedish Radiation Safety Authority, 2008-11-11
Event date: Wed, 21-05-2008