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Press Release (May 26,2011)
Detection of trace amount of radioactive materials by the regular monitoring at Kashiwazaki-Kariwa Nuclear Power Station (continued report)

As part of the regular sampling analysis*1, we have been continuing 
regular monitoring of the radiation of environmental samples such as 
seawater close to the plant, soil, pine needle and etc. Although we have 
detected trace amounts of nuclides such as Cesium and Iodine, released 
into the atmosphere from Fukushima Daiichi Nuclear Power Station, the 
detected figures will not have significant impact to the surrounding 
environment thus far.
             (Previously announced on April 13th, 2011 and May 13th, 2011)
Today, we have conducted as a regular sampling, and detected trace amount 
of Iodine-131 that slightly exceeded the detectable lower limit from the 
seaweeds (sargasso*2) collected at the discharge canal (2 spots) on May 
23rd, 2011.
(please refer to the attachment for the result of the analysis)

As there was no abnormality found with the operation and works of the 
units, readouts of the exhaust stack monitors and sea water monitors, it 
is presumed that nuclides released into the atmosphere from Fukushima 
Daiichi Nuclear Power Station were collected and detected in 
Kashiwazaki-Kariwa Nuclear Power Station.

As the monitored figures for Iodine-131 (maximum 0.23 Bq/kg fresh weight*3) 
were the eight thousandth part of the ingestion limit established in the 
Index for Nuclear Disaster Prevention*4 (2,000Bq/kg fresh weight), they 
were at extremely low level.
In addition, the aggregate monitored figure of radiation dose from the 
nuclide is approximately 8 x 10-5mSv per year, if a person continuously 
ingest for a year. That is the thirty thousandth part of radiation a 
person receives from nature annually (2.4 mSv). Furthermore, it is far 
lower than radiation dose from one time chest X-ray examination (0.05 mSv).

We will implement the ashing process of the samples and measure the 
nuclides such as radioactive cesium, and will conduct regular sampling and 
analysis of radiation level of the other environmental samples.

Attachment-1: Monitoring result of radioactive materials by regular 
              monitoring in Kashiwazaki-Kariwa Nuclear Power Station
                                                          (PDF 26.1KB)
Attachment-2: Detected location of trace amounts of radioactive materials 
              by regular monitoring in Kashiwazaki-Kariwa Nuclear Power 
              Station(PDF 88.2KB)
*1: Environmental sampling analysis
In order to investigate the impact of radioactive materials in the power 
station pursuant to "Agreement on Safety Assurance for Surrounding Areas 
of Nuclear Power Station" (known as [Safety Agreement]), we are 
investigating the radiation materials of seawater, soil, pine needle, milk, 
etc around the power station periodically. 

*2: Sargasso
A kind of seaweed regarded as the Index organism of environmental 
monitoring as it tends to concentrate nuclides in the ocean. We conduct 
the sampling quarterly basis in order to analyze the accumulation of nuclides.

*3: Bq/kg fresh weight
Amount of radiation dose contained in the 1 kg of fresh seaweed

*4: Ingestion limit established in the Index for Nuclear Disaster 
Prevention
The index concerning the limited ingestion of radiation contaminated food 
and drink which Nuclear Safety Commission established in "Disaster 
Prevention Measures at Nuclear Facilities".

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