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Press Release (Mar 24,2011)
Detection of trace amounts of radioactive iodine around an exhaust stack and others of Kashiwazaki-Kariwa Nuclear Power Station
TEPCO has measured exhaust air from an exhaust stack and vent of each
building of Kashiwazaki-Kariwa nuclear power station with a filter for 
a week, and detected iodine 131 up to 2.4 X 10-8 (becquerel/cm3) at 
the exhaust stacks of all buildings, the exhaust vents of service
buildings and auxiliary buildings (Arahama-side) of Unit 3, 5 and 6.

It slightly exceeded the upper limit (please refer to the attachment for
more information).

Therefore, TEPCO checked operation conditions and works of all units,
readings of high sensitivity off gas monitor*1, a periodical analysis
result of iodine 131 contained in reactor water of Unit 1, 5, 6 and 7
in operation.  However, any abnormality was detected.

It is presumed that iodine 131 released into the atmosphere from
Fukushima Daiichi Nuclear Power Station was collected and detected
in Kahiwazaki-Kariwa Nuclear Power Station, since iodine 131 was detected
in radioactivity measurement of the exhaust air of some units and no
abnormality of iodine 131 in nuclear water was detected.

Readings of monitoring posts and dust radiation monitors are within
the normal range and have little environmental impact.The monitoring
posts are located at boundary of the station and measure an ambient
dose rate.  The dust radiation monitors*2 are located beside 
the monitoring posts.

Attachment: :measurement result of iodine 131 in 
             Kashiwazaki-Kariwa Nuclear Power Station

*1: High sensitivity off gas monitor 
    Measurement equipment installed in an off-gas treatment system to 
    detect minimal leakage of radioactive materials from fuel rods to 
    the nuclear water early

*2: Dust radiation monitor
    Measurement equipment to monitor radioactivity contained in dust
    which is collected around boundary of the nuclear power station.
    Three dust radiation monitors are installed beside
    the monitoring posts.
    
attachment1:measurement result of iodine 131 in
            Kashiwazaki-Kariwa Nuclear Power Station 
attachment2:Detection of trace amounts of radioactive iodine around an
            exhaust stack and others of Kashiwazaki-Kariwa Nuclear Power 
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