Sixty holes violating the Building Standards Act were found recently in firewalls at the Kashiwazaki-Kariwa nuclear plant in Niigata Prefecture, in addition to two similar holes found in July this year, plant operator Tokyo Electric Power Co. (TEPCO) announced Nov. 22.
Of the 60 holes, 49 date back to the 1980s when the No. 1 reactor building was built, revealing administrative agencies' lack of consideration for proper construction management.
Reactor buildings have several thousand holes in them for pipes. Of these holes, those going through firewalls are required to have any gaps filled in with mortar caulk or other nonflammable material. In July, TEPCO found two holes in a firewall in the No. 2 reactor building that had not been properly filled in. A subsequent inspection of the entire plant found that 60 holes had not been filled in -- a building code violation -- of which 41 were in radiation-control areas.
The power company will begin taking countermeasures, such as filling the holes in, as early as the beginning of the New Year. "At the time the reactor buildings were built, our awareness of the risks was insufficient," TEPCO spokesperson Yoshimi Hitosugi said.