On April 4th, 2011, we reported on the preventive measures to be taken
after receiving severe warning from Nuclear and Industrial Safety Agency
(NISA) on April 1st in regard to the results on nuclide analysis at
Fukushima Daiichi Nuclear Power Station.
                                 (Previously announced on April 4th, 2011)

Accordingly, we would like to inform the results of re-evaluation on
nuclide analysis in regard to samples collected before March 30th from
accumulated water in the turbine building, water in the trench and
sub-drain (subsurface water) near the turbine building, together with
accumulated water detected in the Process Main Building of Centralized
Radiation Waste Treatment Facility. The re-valuation was conducted in
accordance with the preventive measures.

The preventive measures are as follows and re-valuation was conducted
based on such measures.

<Preventive measures>
1.Evaluation of nuclide analysis based on experts' opinion
 Experts from third-party institution verified the concept of nuclide
 identification and evaluation was conducted after reflecting such
 experts'opinions.

2.Deliberation on the method of cross-check
 Experts from manufacturer confirmed the adequacy of nuclide library in
 the analytical equipment. In addition, experts from third-party
 institution confirmed the adequacy of concept in regard to program used
 for nuclide analysis evaluation.

3.Improvement of accuracy achieved by support from other institutions,
  such as electric utilities
 We attempted to improve the accuracy of nuclide analysis evaluation by
 asking other electric utilities and third-party institutions for support
 on reviewing data and adequacy.

4.Preparation of preliminary report and definite report
 In order to achieve good balance between accuracy and promptness, we made
 announcement in 2 stages. Firstly, we released a preliminary report
 (determination of radioactivity density regarding the 3 major nuclides,
 while providing them as reference data in the results of nuclide analysis)
 and thereafter a definite report (determination and announcement of
 radioactivity density regarding major nuclides as well as other nuclides).
                                (Previously announced on April 20th, 2011)

We would like to inform the results of re-evaluation, confirmed in
accordance with the preventive measures, on nuclide analysis in regard to
the samples collected before March 30th from the air at the site of power
station and seawater near the power station.
In addition, we would like to inform a definite report of the results on
nuclide analysis in regard to the samples collected during the period of
March 31 to April 23 from the air at the site of power station, seawater
near the power station, seawater near the shallow draft quay and bar
screen of Unit 2, sub-drain water near the turbine buildings, sub-drain
water near Centralized Radiation Waste Treatment Facility, and others.

We will inform the results of re-evaluation on nuclide analysis in regard
to the samples collected after April 24th from the air at the site of
power station and seawater near the power station, after confirming them
in accordance with the preventive measures. 

Appendices
Attachment-1: Result of Nuclide Analysis of Radioactive Materials in the 
              Air at the Site of Fukushima Nuclear Power Stations 
                                                            (PDF 293KB) 
Attachment-2: Results of Nuclide Analysis of Seawater (PDF 437KB) 
Attachment-3: Results of Nuclide Analysis of Seawater Offshore(PDF 87.9KB) 
Attachment-4: Results of Nuclide Analyses of Sub-drains (PDF 37.1KB) 
Attachment-5: Fukushima Daiichi Results of nuclide analysis of accumulated 
              water in the Process Main Building of Centralized Radiation 
              Waste Treatment Facility (PDF 20.4KB)