With regard to the plant's parameters related to each Unit of Fukushima
Daiichi Nuclear Power Station posted on our homepage since April 18th,
2011, it is confirmed that there are some mistakes in the data and
therefore we are now verifying the data.
(Previously announced on April 24th, 2011)

In the verifying process, we have confirmed that there were some mistakes
in the part of the data measured by Containment Atmospheric Monitoring
System (CAMS)*1. The data measured by CAMS is important as it is used to
estimate the core damage ratio*2 of Unit 1 to 3 of Fukushima Daiichi
Nuclear Power Station. Therefore, we have reported it to Nuclear and
Industrial Safety Agency (NISA) today.

We have confirmed the mistakes as shown in the references.

Reference 1: The data of Unit 1 to 3 of Fukushima Daiichi Nuclear Power 
             Station measured by CAMS and erratum sheet of the core damage 
             ratio (PDF 49.3KB) 
 
Reference 2: Core damage ratio of Unit 1 to 3 of Fukushima Daiichi Nuclear 
             Power Station (PDF 462KB) 
 
*1 Containment Atmospheric Monitoring System (CAMS): The system to monitor
   the radiation in the containment vessel (dry well side / wet well side)
   after the loss-of-coolant accident

*2 Core damage ratio: The ratio of the fuel rods (fuel cladding) damaged
   by the temperature increase, etc. out of all the fuel rods
   (fuel cladding)