Environmental radioactivity at the National Nuclear Research Centre, Pelindaba

The revised environmental survey program, introduced during 1970 with the emphasis on monitoring of the critical paths of exposure of the general public, was continued in 1975. The analytical method for 131I in milk was improved to give a lower detection limit, and the gamma background survey now also includes a more specific measurement for 131I. Results of determinations of both gross radioactivity and individual nuclides in samples of fish and water (which are critical materials for liquid-effluent releases) from the Hartbeespoort Dam and from the Crocodile River, are given and discussed. Results of gamma-spectrometric 131I and 0Sr analyses of milk, the critical material for releases to the atmosphere, are presented. Results are given of regular investigations of the composition of effluent releases which were well below the permissible levels. Levels of deposited and airborne activity from nuclear-bomb tests are reported. No environmental radioactivity resulting from NNRC releases could be detected above the fallout levels