Ronan Kelly
Retired 2020
Press Release (Apr 13,2011)
Detection of trace amount of radioactive materials by the regular monitoring at Kashiwazaki-Kariwa Nuclear Power Station (continued report)
We have been measuring radioactive materials by the dust radiation monitor*1
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 that slightly
exceeded the detectable lower limit from filters installed at three
locations when we conducted the regular monitoring for March 2011.
Detected nuclides are Cesium-134 and Cesium-137. (please refer to the
attachment for more information).
Therefore, TEPCO checked operating conditions and works of all units,
readouts of the exhaust stack monitors and the sampling result of water in
the reactor. As no abnormality was detected, 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 monitored figures of Cesium-134 were the two millionth part of the
density limit in the air, 2 x 10-5 Bq/cm3 (Announcement density*2),
meanwhile, Cesium-137 were the four millionth part of 3 x 10-5 Bq/cm3.
(Announcement density), these figures indicated extremely low level.
In addition, the aggregate monitored figure of radiation dose from Cesium
was approximately 7 x 10-7mSv per year. That was the three millionth 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).
As part of the regular sampling analysis*3, we will continue monitoring
the radiation of environmental samples such as seawater close to the plant,
soil, pine needle and etc.
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.
Attachment-1: Monitoring result of radioactive materials by regular
monitoring in Kashiwazaki-Kariwa Nuclear Power Station http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110413e3.pdf
Attachment-2: Detected location of trace amounts of radioactive materials
by regular monitoring http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110413e4.pdf
*1: 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.
*2: 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.
*3: Environmental sampling analysis
We are monitoring the radiation of seawater close to the plant, soil,
pine needle, milk and etc periodically.
http://www.tepco.co.jp/en/press/corp-com/release/11041305-e.html
Detection of trace amount of radioactive materials by the regular monitoring at Kashiwazaki-Kariwa Nuclear Power Station (continued report)
We have been measuring radioactive materials by the dust radiation monitor*1
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 that slightly
exceeded the detectable lower limit from filters installed at three
locations when we conducted the regular monitoring for March 2011.
Detected nuclides are Cesium-134 and Cesium-137. (please refer to the
attachment for more information).
Therefore, TEPCO checked operating conditions and works of all units,
readouts of the exhaust stack monitors and the sampling result of water in
the reactor. As no abnormality was detected, 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 monitored figures of Cesium-134 were the two millionth part of the
density limit in the air, 2 x 10-5 Bq/cm3 (Announcement density*2),
meanwhile, Cesium-137 were the four millionth part of 3 x 10-5 Bq/cm3.
(Announcement density), these figures indicated extremely low level.
In addition, the aggregate monitored figure of radiation dose from Cesium
was approximately 7 x 10-7mSv per year. That was the three millionth 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).
As part of the regular sampling analysis*3, we will continue monitoring
the radiation of environmental samples such as seawater close to the plant,
soil, pine needle and etc.
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.
Attachment-1: Monitoring result of radioactive materials by regular
monitoring in Kashiwazaki-Kariwa Nuclear Power Station http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110413e3.pdf
Attachment-2: Detected location of trace amounts of radioactive materials
by regular monitoring http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110413e4.pdf
*1: 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.
*2: 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.
*3: Environmental sampling analysis
We are monitoring the radiation of seawater close to the plant, soil,
pine needle, milk and etc periodically.
http://www.tepco.co.jp/en/press/corp-com/release/11041305-e.html