Radiological constituents

Most of the definitions are not explicit in regard to the primary constituents of the waste or its radiological properties. 

Outside the organic and inorganic constituents, the traditional approach may find favor for tests of other constituents. Currently, radiological testing appears to be such a case. Here the economics are reversed from those presented above and it is more feasible to issue traditional PT materials from NIST on a regular, periodic schedule. 

Further evidence for the ability of chemical processes within the shale to retard important radionuclides, is provided by the distribution of Ce and Ba. These elements are chemical analogues for the radiologically important elements Th and Ra respectively, which are important constituents of many radioactive wastes. The elevated levels of Ce and Ba in the shale matrix, compared to the levels in the calcite veins (Table 2) may be evidence that these elements were relatively immobile during the formation of the calcite veins. An implication is that Th and Ra would also have been relatively immobile under these conditions (undisturbed far-field conditions). Such investigations require, however, better characterization of the mineral sinks for Ba, Ce and other trace elements, and determination of the calcite crystallization mechanisms. 

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