The Radiation and Nuclear Safety Authority (STUK) informed on its own website on 14 April under the section Surveillance News that Teollisuuden Voima, TVO, had detected and subsequently defects and deficiencies in the seals of the connectors of third unit (OL3) of the Olkiluoto nuclear power plant.
The seals are required in the event of an accident. Should the seals be missing, the measurements required for containing the accident could be affected, compromising the safety functions of the plant.
As the incident was accompanied by inadequate guidance and the defect was detected in several locations, TVO concluded that the incident falls under category one on the International Nuclear and Radiological Event Scale (INES). According to the INES, the incident was classified as an Anomaly. The absence of a single seal as such is not a safety issue, but the recurrence of the error increased the significance of the incident on the assessment scale.
TVO submitted its own assessment to STUK in connection with the incident report in April, and STUK made a decision based on its own assessment, in which it concurs with TVO’s INES assessment.
Link to web page INES International Nuclear Event Scale INES
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