The Section maintains the data acquisition system in a state of readiness, for use in locating and mapping radiation spills from nuclear accidents and for use in studies of nuclear waste disposal areas.

In January 1978, the USSR's nuclear-powered Cosmos 954 satellite [1] fell to earth [2] and scattered radioactive debris across the Northwest Territories near Yellowknife in northern Canada [3]. During the 3 month search & cleanup operation, the Section's innovative full-spectrum system was re-tuned to detect radiation from man-made sources [4] (Bristow, 1978) and was successful in locating 500 pieces of radioactive debris [5] for subsequent disposal [6].

Operation Morning Light was documented in an illustrated non-technical report (NTIS, 1978) prepared by the US National Technical Information Service. An illustrated report from the Atomic Energy Control Board of Canada (Gummer et al, 1980) is equally readable, but with more details of the recovered debris. A personal account of the operation by Q. Bristow also makes for interesting reading.

[1] [2] [3]

[4] [5] [6]

The Radiation Geophysics Section also provides assistance to geologists and geophysicists from other countries in analyzing and processing their airborne gamma-ray survey data. The Section processed a data set flown over a nuclear reactor spill in Eastern Europe (Rangelov et al, 1993). The extent of the contamination from reactor products is evident in the Cobalt-60 map [7] and in the Exposure Rate map (superimposed on a high-resolution SPOT satellite image) [8]. Both maps clearly show the reactor and the path of the spill down two drainage ditches/canals (1993, GSC Open File 2573).

[7] [8]

Radon is a colourless, odourless radioactive gas that occurs naturally in our environment. It is produced by the natural breakdown (radioactive decay) of uranium. Radon can be found in high concentrations where soils and rocks contain uranium, granite, shale or phosphate. Radon may also be found in soils contaminated with certain types of industrial waste, such as the by-products of uranium or phosphate mining.

These are maps of the exposure rate at ground level of gamma radiation emitted by nuclear reactors:

Argon-41 (Ar⁴¹) is produced by the activation of Argon-40 (Ar⁴⁰) present in the air circulating through the reactor. In the most radioactive part of the plume, the calculated exposure rate at ground level was found to be about three times the average natural background radiation in Canada, but no higher than the natural level in many parts of Canada (Grasty, 1983).

Uranium map derived from airborne gamma-ray spectrometry measurements over the town of Port Hope, Ontario, showing low level radioactivity from storage areas and contaminated fill from the refinery at Eldorado Resources Ltd.