On March 28 2011, we were advised from Nuclear Safety Commission of Japan 
to enhance sampling surveys regarding water accumulated in underground 
floor of the turbine buildings of Fukushima Daiichi Nuclear Power Station. 
In order to verify any leakages to underground and sea, and safety, we 
have been implementing the sampling surveys of subsurface water and seawater.

Regarding sampling of sub-drains, per the instruction from Nuclear and 
Industry Safety Agency (NISA) on April 14, we will continue the same kind 
of sampling surveys three times a week, and inform the result on the next 
day of the survey.
                                                   (Previously announced)

We collected samples from sub-drains (subsurface water obtained and managed 
in the site) near the turbine buildings of Fukushima Daiichi Nuclear Power 
Station collected on September 28, and conducted nuclide analysis. As a 
result, radioactive materials were detected as shown in the appendix. 

Also, we analyzed plutonium in the water of sub-drains sampled on September 
12, tritium, total alpha rays and total beta rays contained in the water of 
sub-drains sampled on August 15. As a result we have detected some tritium 
and total beta rays as shown in the attachment.

Today, we reported the results to NISA and the government of Fukushima 
Prefecture. 

 
Appendix1: Result of nuclide analysis of sub drain of Fukushima Daiichi NPS 
                                                               (PDF 10.3KB)  
Appendix2: Pu analysis result at sub-drains of Fukushima Daiichi Nuclear 
           Power Plant (PDF 14.5KB)  
Appendix3: Radioactivity Density of Sub-drain (PDF 22.2KB)