At Fukushima Daiichi Nuclear Power Station, all monitoring posts (8 places) 
and transmitters were unable to use due to blackout caused by the 
Tohoku-Chihou-Taiheiyou-Oki Earthquake. Until those equipment were resumed, 
we temporally measured the radiation dose by monitoring cars (mobile 
measuring vehicle) and radiation administrators collected, sorted and 
recorded the data by hand. During that time, it was not good condition 
for monitoring as communication line and intra-LAN were frequently down 
and the collected data were sometimes handed over person to person.

Therefore, different from normal situation, it was impossible to open the 
monitoring data to our homepage automatically on real time. However, in 
order to release as soon as possible, the collected data were faxed to 
the Tokyo Head Office, then the Head Office manually input the data onto 
our homepage as much as possible from 17:30 March 11, even though the 
data were imperfect form.

In confusion after the earthquake, every department struggled to announce 
the information regarding radiation dose as soon as possible. In addition 
to the communication for radiation administration by related departments 
between the Power Station and the Head Office, there was another 
interchange of information for public relations regarding early 
publication at the homepage. As a result, it was found that there were 
some mismatch between disclosed data on the homepage and others.

Meanwhile, in order to gather data as much as possible, we deployed a 
monitoring car dispatched from Kashiwazaki-Kariwa Nuclear Power Station 
around MP4 area from about 15:00, March 12 to about 12:00, March 14. 
This monitoring car can collect the data every two minutes; however, we 
normally disclose the monitoring data as 10 minutes interval, so that we 
followed this principle. 

We had executed the verification between possessing data and published 
one. Today, we decide to disclose whole date regarding radiation dose 
afresh. 

Appendix1:Results of Monitoring at Fukushima Daiichi Nuclear Power 
                                                 Station(PDF 192KB) 
                                               CSV Download(23.4KB)