TNAG-1508-FCO40-2066-Guangdong-nuclear-power-station-project-at-Daya-Bay-safety-c-1987 — Page 101

This ray, just like the fluorescence in the dark of the night,

can be detected by advanced instruments with high sensitivity

wherever it goes; hence a very ideal tracing material, a a tracer

atom as it is generally termed.

When compared with other tracing material, the tracer atom

has more advantages as follows:

1. Very high sensitivity;

2. Extremely small quantity needed;

3. Impervious to interference by environments, (such as high

temperature, high pressure, etc);

4. Better capacity in reflecting the true objective condit-

ions, as the tracer atom is identical with the traced material

in chemical properties.

By adopting the tracer atoms for the purpose of tracing

(i.e. the isotopic tracing technology), one certain molecule.

can be found out from among 100 billion molecules. To put it

more directly, one grain of corn can be distinguished out of

850 train wagons of corn, whereas the non-nuclear methods (e.g.

the method of chemical standardization) can only distinguish

a certain molecule from among 10 million molecules, that is,

distinguish a certain grain of corn out of one tenth of a train

wagon of corn.

Radioactive isotope tracing technology is the most widely

used isotopic tracing technology at present. Moreover,

isotopic tracing technology also includes stable isotopic

tracing technology, activatable tracing technology and environ-

mental isotopic tracing technology.

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