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. We have been measuring radioactive
materials by the dust radiation monitor at three of the monitoring posts
installed at the station boundary, collecting the dust in the atmosphere
as environmental sample with a filter. On April 13th, we detected trace
amounts of Cesium-134 and Cesium-137 that slightly exceeded the detectable
lower limit from filters installed at three locations when we conducted the
regular monitoring for March 2011.
As a result of the survey, no abnormality was found with all the unit
status, readouts of the exhaust stack monitors and the sampling result of
water in the reactor of Kashiwazaki Kariwa Nuclear Power Station, it is
presumed that Cesium-134 and Cesium-137 released into the atmosphere from
Fukushima Daiichi Nuclear Power Station were collected and detected in
Kashiwazaki-Kariwa Nuclear Power Station.
The detected figures will not have significant impact to the surrounding
environment.
(reported on April 13th, 2011)
Up until today, we have conducted, as a regular sampling for the month of
April, same sampling and analysis of the filters of dust monitoring post
and similar to the previous month of March, we detected trace amounts of
nuclide that slightly exceeded the detectable lower limit from the filters
installed at three locations.
Detected nuclides are Cesium-134, Cesium-137, Niobium-95 and Tellurium
129m. (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 the sampling result of
water in the reactor of Kashiwazaki Kariwa Nuclear Power Station, 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.
The monitored figures for each of Cesium-134 were the thirty thousandth
part of the density limit in the air, 2 x 10-5 Bq/cm3 (Announcement
density*2), Cesium-137 were the fifty thousandth part of 3 x 10-5 Bq/cm3
(Announcement density), Niobium-95 were eight millionth part of the density
limit in the air, 7 x 10-5 Bq/cm3 (Announcement density*2), and Tellurium
129m were one hundred thousandth part of the density limit in the air, 7 x
10-5 Bq/cm3 (Announcement density*2), these figures are indicating
slightly low level as shown above.
In addition, the aggregate monitored figure of radiation dose from the
nuclide was approximately 6 x 10-5mSv per year. That was the forty
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).
Readouts of Monitoring Posts located at boundary of the station and dust
radiation monitors attached to Monitoring Posts are within the normal
range. There is no impact to the surrounding environment.
We will continue to conduct regular sampling and analysis of radiation
level of environmental samples.
Attachment-1: Monitoring result of radioactive materials by regular
monitoring in Kashiwazaki-Kariwa Nuclear Power Station
(PDF 7.92KB)
Attachment-2: Detected location of trace amounts of radioactive materials
by regular monitoring(PDF 34.1KB)
*1: Environmental sampling analysis
We are monitoring the radiation of seawater close to the plant, soil, pine
needle, milk and etc periodically.
*2: Dust radiation monitor
Measurement equipment to monitor the radiation of the dust in the
atmosphere is collected consecutive every 6 hours with a filter. We have
been implementing detailed analysis of used filter periodically.
Three dust radiation monitors are installed out of nine points of the
monitoring posts near the station boundary.
*3: Announcement density
This density is established as the equivalent radioactive dose of 1 mSv per
year if a person continues breathing the same through the year.
