Fukushima Daiichi NPS Prompt Report 2013

At around 3:45 AM today (on July 5), in the central operation room (hereinafter, COR) of the Fukushima Daiichi NPS Unit 5, a night-shift worker (a TEPCO employee) who was on a patrol inside the COR found that the standby failure indicator of the generator (B) of the two emergency diesel power generators (hereinafter, D/Gs) was on. (The standby failure indicator is a lamp for indicating that the D/G is not in the standby state).

The other generator (A) of these D/Gs was found to be in the standby state.

An investigation was later conducted, and revealed at 5:59 AM that the standby failure indicator was turned on due to malfunction of a circuit that detects the position of a fuel handle (a device to block fuel supply to a D/G) attached to the main body of the D/G.

At present, as the position detection circuit has been removed, the standby failure indicator is off, and we confirmed that the fuel handle is at the normal position.

The cause of this incident is currently under investigation, and we will make an announcement as soon as we find the cause.