Fukushima Daiichi NPS Prompt Report 2013

Today (on June 29), an incident occurred where one in-station service vehicle (a concrete mixer truck) at Fukushima Daiichi Nuclear Power Station went out of the station premises (outside from the main gate) with contamination attached to the upper part of the rear bumper and without having been decontaminated.

This vehicle underwent a vehicle survey after the completion of its work in the station premises, was found having contamination (22,000cpm) attached to the upper part of the vehicle's rear bumper, and received a decontamination instruction. At 1:26 PM, however, this vehicle left the premises through the main gate without having been decontaminated.

Later, the vehicle was loaded with concrete in Naraha-machi, reentered into the station premises and carried out some work. Then, the vehicle underwent the vehicle survey again in order to receive permission to leave the premises, and was again found having contamination (20,000cpm) attached to the same part. After being found having contamination for the second time, the vehicle underwent decontamination, and was confirmed to be at a contamination level (3,000cpm) that is lower than the benchmark value (13,000cpm) used for permitting a vehicle to leave the station.

At 4:27 PM on the same day, regarding the route and so on where this vehicle travelled, we started confirming whether there are influences of the travelling of this contaminated vehicle. We will make a separated announcement on the result of this conformation as soon as we obtain the result.