How Toxic is Nuclear Waste
Over 10 Million Years?

The following chart is taken from a very interesting circular published by the US Geological Survey on the subject of High Level Radioactive Wastes (HLW). In order to compare the toxicity of HLW with (for example) uranium mill tailings, it is necessary to have a crude measure of the toxicity of radioactive materials in general. This is provided by using drinking water standards, which specify -- for each radioactive substance -- the maximum concentration that is permissible in drinking water. Thus a crude measure of toxicity can be obtained by calculating the amount of water needed to dilute a given quantity of radioactive material to the maximum permissible level of radioactive pollution that is legally permitted for drinking water. When this is done, it can be seen that -- after the first thousand years or so -- uranium mill tailings are in fact more hazardous than the HLW.

Figure 1 * Ingestion hazard of selected radionuclides in high-level waste during ten million years. The radiotoxic hazard measure is obtained by dividing the number of curies present for a given nuclide by the number of curies produced by the maximum permissible concentration of that nuclide in a cubic meter of drinking water. Data are normalized for one metric ton of light-water reactor fuel. The nuclide curves are plotted from data in table 2 of Hamstra (1975); the curve for uranium mill tailings was derived from figure 2 of Hamstra (1975) and figure 7 of Pigford and Choi (1976).

* from Geologic Disposal of High-Level Radioactive Wastes -- Earth-Science Perspectives
U.S. Geological Survey
Circular 779

by J.D. Bredehoeft et al (U.S. Gov't Printing Office, 1978)

239Pu = Plutonium-239
226Ra = Radium-226
237Np = Neptunium-237
229Th = Thorium-229
233U = Uranium-233

[Findings on Uranium Tailings]

[Findings on High-Level Waste]



  • Hamstra, J. [1975] Radiotoxic hazard measurement for buried solid radioactive waste. Nuclear Safety, v. 16, n. 2, pp. 180-189.

  • Pigford, T.H. and Choi, Jor-Shan. [1976] Effect of fuel cycle alternatives on nuclear waste management. In Post, R.G. (ed.) Proceedings of the Symposium on Waste Management , Tucson, Arizona, October 3-6, 1976. [ U.S. Energy Research and Development Administration ERDA Report CONF-761020, pp. 39-57 : Available from Natl. Tech. Inf. Service, Dept. Commerce, Springfield Va, 22151 USA ].
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