• Applications of the Use of Hawthorn Berries in Monitoring 14C Emissions from a UK Nuclear Establishment Over an Extended Period

      Walker, A. J.; Otlet, R. L.; Longley, Harry (American Journal of Science, 1986-01-01)
      The paper describes a study undertaken to examine the dispersion pattern of gaseous emissions, as indicated by 14C uptake in natural materials, around the nuclear reprocessing plant at Sellafield, Cumbria, UK. The extent and directional dispersion of the released 14C is established and its variability over an extended period assessed. Results of measurements taken during three sampling seasons (1981,1982,1983) of the 14C activity in hawthorn berries collected over a wide area are presented and the dispersion pattern contours constructed from them are examined. Only limited agreement of the results with the theoretical relationship 1/r is found and both meteorology and topography are seen to be important in determining the shape of the observed patterns.
    • Global and Local Effects of 14C Discharges from the Nuclear Fuel Cycle

      McCartney, Martin; Baxter, M. S.; McKay, Keith; Scott, E. Marian (American Journal of Science, 1986-01-01)
      The radiologic impact of 14C produced by the nuclear fuel cycle is assessed at both global and local levels. In the former context, it is predicted here that the specific activity of atmospheric CO2 in the year 2050 will be ca 7.6 pCig^(-1)C. Although this is similar to the present level, the subsequent collective dose commitment could be highly significant. The enhancement of 14C concentrations around the nuclear fuel-reprocessing plant at Sellafield (Windscale) in Cumbria, UK has been monitored over recent years. For example, maximum levels of 27.2 pCig^(-1)C (~350% above natural) during 1984 were observed <1 km from the plant, with enhanced activities detectable to at least 29km. Nevertheless, it is clear that the radiologic significance to the local population is low. The spatial distribution of the excess 14C allows atmospheric dispersion models to be tested in the context of continuous releases and the results thus far show that the Gaussian plume model performs successfully.
    • Institut Royal du Patrimoine Artistique Radiocarbon Dates XI

      Dauchot-Dehon, Michele; Van Strydonck, Mark; Heylen, Jon (American Journal of Science, 1986-01-01)
    • Sample Credentials Necessary for Meaningful High-Precision 14C Dating

      Jope, E. M. (American Journal of Science, 1986-01-01)
      Samples presented for high-precision 14C dating must satisfy stringent requirements if the 14C determinations are to yield meaningful sharp calendric dates, such as are now possible with the bidecadal high-precision calibration curve. The total carbon content should come from a confined time range 10-20 years (10-20 tree rings in wood or charcoal) appropriate for the bidecadal calibration curve. For accurate calendric dating the relation of these rings to the outer growth rings must be known. Application of the high-precision calibration curve to some archaeologic examples is discussed. It is now up to archaeologists and geoscientists to use this refined chronometric instrument to fullest advantage.
    • University of Wisconsin Radiocarbon Dates XXIII

      Steventon, Raymond L.; Kutzbach, John E. (American Journal of Science, 1986-01-01)