Radiological Monitoring at Canadian Nuclear Power Plants
The CNSC has requested that all Canadian nuclear power plant licensees continue the regular radiation monitoring of air, land and water at their plant sites as part of their ongoing operations and report to the CNSC on specific radioisotopes that would indicate any changes from normal background levels that may results from the incident at the Fukushima Daiichi Nuclear Power Plant.
April 19, 2011
Pickering
Ontario Power Generation recently reported to the CNSC that the extensive radiological environmental monitoring program at their Pickering Nuclear Generating Station detected no increase of Iodine-131 (I-131) in tests taken from mid to late March.
Darlington
Ontario Power Generation recently reported to the CNSC that the extensive radiological environmental monitoring program at their Darlington Nuclear Generating Station detected traces of Iodine-131 (I-131) in a small number of samples.
Analysis of samples taken in mid to late March 2011 indicates a small increase from the normal I-131 values in the range of 0.5 mBq/m3 to 1.8 mBq/m3. These are very small quantities of I-131 and can only be measured with very sensitive equipment. It has been concluded that this I-131 is likely the result of emissions of I-131 from the Fukushima plant in Japan.
Based on the maximum value detected as above, the effective dose to a person would be approximately 0.0025 µSv, if a person breathed in this concentration of air, and was exposed externally to this air for an entire month (31 days). For these reasons, this estimate is very conservative.
This dose corresponds to 0.0025% of the CNSC effective dose limit of 1 mSv per year to a member of the public, from licensed activities and is an even smaller percentage of the total effective dose from all sources of radiation to which Canadians are exposed. The presence of these concentrations of I-131 in the air will not produce harmful effects to the health of Canadians.
* 1 Bq = 1000 mBq
March 31, 2011
NB Power
NB Power recently reported to the CNSC that their extensive radiological environmental monitoring program detected traces of Iodine-131 (I-131) in a small number of samples.
Analysis of samples taken in mid to late March 2011 indicated a maximum of
0.36 x 10-3 Bq/m3 (0.36 mBq/m3)* of Iodine-131. This is a very small quantity of I-131 and can only be measured with very sensitive equipment. It has been concluded that this I-131 is likely the result of emissions of I-131 from the Fukushima plant in Japan.
Based on the maximum value detected as above (0.36 mBq/m3), the effective dose to a person would be approximately 0.005 µSv, if a person breathed in this concentration of air, and was exposed externally to this air for an entire month. This estimated dose does not take into account the radioactive decay that would occur during that time. For these reasons, this estimate is very conservative.
This dose corresponds to 0.0005% of the CNSC effective dose limit of 1 mSv per year to a member of the public, from licensed activities and is an even smaller percentage of the total effective dose from all sources of radiation to which Canadians are exposed. The presence of these concentrations of I-131 in the air will not produce harmful effects to the health of Canadians.
Bruce
Bruce Power recently reported to the CNSC that their extensive radiological environmental monitoring program detected traces of Iodine-131 (I-131) in a small number of samples.
Analysis of samples taken in mid to late March 2011 indicated a maximum of
2.0 x 10-3 Bq/m3 (2.0 mBq/m3) of Iodine-131. This is a very small quantity of I-131 and can only be measured with very sensitive equipment. It has been concluded that this I-131 is likely due to the result of emissions of I-131 from the Fukushima plant in Japan.
Based on the maximum value detected as above (2.0 mBq/m3), the effective dose to a person would be approximately 0.03 µSv if a person breathed in this concentration of air, and was exposed externally to this air for an entire month. This estimated dose does not take into account the radioactive decay that would occur during that time. For these reasons, this estimate is very conservative.
This dose corresponds to 0.003% of the CNSC’s effective dose limit of 1 mSv, per year, to a member of the public, and is an even smaller percentage of the total effective dose from all sources of radiation to which Canadians are exposed. The presence of these concentrations of I-131 in the air will not produce harmful effects to the health of Canadians.
* 1 Bq = 1000 mBq
For further information on radiological monitoring, refer to these Web sites:
CNSC
- Radiation Dose Rates in Canada
- Types and Sources of Radiation
- Radiation Dose
- Health Effects of Radiation (including dose from common medical practices)
- Radioactive Release Data from Canadian Nuclear Power Plants 1999-2008 (PDF)
Health Canada
- Canadian Drinking Water Guidelines
- Canadian Radiological Monitoring Network
- Fixed Point Surveillance Network
- Exposure to Ionizing Radiation Fact Sheet
- Recommendations on Dose Coefficients for Assessing Doses From Accidental Radionuclide Releases to the Environment