31 Janvier 2016
Jan. 29, 2016 - Updated 13:33 UTC+1
Tokyo Electric Power Company submitted a report on Friday to the Nuclear Regulation Authority on an installation error at a nuclear power station in Niigata Prefecture.
2,500 electrical cables were incorrectly laid. The problem was found last year at the Kashiwazaki-Kariwa plant on the Sea of Japan coast. Safety cables and regular ones were mixed up. The safety-related cables are used for sending signals to a secure emergency power supply.
New regulations adopted following the Fukushima Daiichi nuclear accident in 2011 require operators to lay the 2 types separately.
The Nuclear Regulation Authority had instructed Tokyo Electric to find the cause of the error.
The utility says in the report that the mistake was found at all 7 of the plant's reactors.
The company says it left the installation work to the contractor. It notes there was no drawing showing cable routes, and that its employees did not check the work.
The company says it will take measures to prevent a recurrence.
The reactors at the plant are currently offline.