Fixed Point Surveillance Network

The Fixed Point Surveillance (FPS) system is an integrated network of radiation detectors across Canada that monitors radiation dose to the public in real-time from radioactive materials in the terrestrial environment, whether they are airborne or on the ground. The detectors are located in every province and territory of Canada with larger numbers near major Canadian nuclear facilities and ports where nuclear powered vessels sometimes harbour. This network monitors external dose from radioactive materials in the environment making Canada better prepared in the event of nuclear or radiological incidents.

The FPS  system measures the total terrestrial gamma dose both as the Ambient Dose Equivalent H*(10) in the unit sievert (Sv) and as the physical dose Air KERMA (Kinetic Energy Released in unit MAss of Material) in the unit gray (Gy).  The measured quantities are typically quite small and are reported as one billionth of a sievert (nSv) or one billionth of a gray (nGy).  Air KERMA is also measured for individual contributions from 3 radioactive gases which escape into the atmosphere during normal operation of nuclear facilities. These three gases are Argon-41, Xenon-133 and Xenon-135. In addition, the system is calibrated to measure external gamma dose rate from Iodine-131 as Air Kerma. Unlike the routinely reported gases, Iodine-131 may be present in the environment in different physical and chemical forms. The minimum detectable dose rates for each of the gases is shown in Table 1 below and represents only a few percent of typical background Air KERMA dose rates (typical background is approximately between 15 nGy/hr and 28 nGy/hr throughout the network). Additionally, these detection limits are well below the acceptable public dose limit of 1 mSv/year (the 1 mSv/year dose limit is approximately equivalent to 0.7 to 1.7 million nGy/year, depending on the radiation source) as published by the Canadian Nuclear Safety Commission in their Radiation Protection regulations.

Table 1 - FPS network minimum detectable dose rates for each of the three primary radioactive gases being monitored.
Nuclide Name Ar-41 Xe-133 Xe-135
Minimum Detectable Dose (nGy/month) 6 3 3

The data from the FPS network can also be used for atmospheric monitoring of many radioactive materials commonly used in medical or industrial applications throughout the country. Iodine-131 is an example of a medical isotope commonly used to diagnose and treat thyroid conditions. Further still, the network can provide information on the general ambient dose rate due to naturally occurring radioactive substances in the ground, air and water.

The network consists of radiation detection equipment located across the country and a single Data Centre that collects, analyses and stores the data measured at each of these monitoring stations. This data centre is located at Health Canada's Radiation Protection Bureau (RPB) in Ottawa and communicates with the stations on a daily or as-needed basis. Currently the network includes monitoring stations installed by Health Canada plus several stations that are owned and operated by industrial partners who share their data with Health Canada. Please click the following link to see a map of the system. FPS Network Map.

The network was partially funded by the federal government's Chemical, Biological, Radiological and Nuclear Research and Technology Initiative (CRTI).

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