We, Tokyo Electric Power Company, have been observing the water level of 
the spent fuel pool of Fukushima Daiichi Nuclear Power Plant Unit 4 since 
April 22nd, 2011. In the course of the observation, we collected 280ml 
pool water on May 7th as we did on April 28th.
As a result of nuclide analysis of radioactive materials contained in the 
pool water, radioactive materials were detected as shown in the appendix, 
and therefore, we reported them to Nuclear and Industry Safety Agency as 
well as to the government of Fukushima Prefecture.

We will further evaluate the matter in detail.

·Appendix: Results of analysis of spent fuel pool water of Fukushima 
           Daiichi Nuclear Power Plant Unit 4 (Update)(PDF 11.7KB)