Since last week, the spikes of radiation level have been recorded at least 8 locations in Fukushima prefecture.
These were observed by the monitoring posts of NRA (Nuclear Regulation Authority).
In Namie-machi, radiation level jumped from 3.7 μSv/h to 110 μSv/h in the afternoon of 7/26/2014.
NRA states the radiation level was in the normal range by measuring the mobile monitor.
They concluded the abnormal reading was due to the malfunction of the monitoring posts caused by summer heat