The report was written in October of last year but has been kept secret until now, SVT’s news programme Aktuellt reports.
The new revelations, described by SVT as “explosive”, are to be broadcast on Monday evening’s show.
The Forsmark 1 reactor was shut down on 25 July 2006 after a short-circuit caused a blackout. Two of four backup diesel generators failed to start automatically, revealing other faults in the power station’s electrical system.
According to the new report, the incident during the summer was partly caused by “a degradation of the company’s safety culture over a long period”.
Aside from the incident that led to the shut-down, renovation work carried out on the power station last year led to 22 workplace accidents and 68 near-accidents, many of which could have proved fatal.
In addition, when 25 workers at the plant were tested for alcohol, 3 were found to be under the influence and had to be sent home.