Surface Contamination Modeling

DOE-HDBK-1132-99

Table III. To this is added the consequences predicted by Le Chatelier'

Principle. From both, we get the fundamental relationship,

2H2 + 2D2 + 2T2

+ HD + D2 + HT + DT + T2 .

(8)

In a terrestrial environment, virtually all of the tritium that exists in nature exists

as water or water vapor. Correcting this situation for the natural conversion to

water and/or water vapor, Equation (8) becomes

W H O + HDO + D O + HTO + DTO + T O .

2H2O + 2D2O + 2T2O

(9)

It can also be assumed that the surfaces of all terrestrially bound objects are

coated with a series of mono-molecular layers of water vapor. In the final step,

it can be assumed that the innermost layers of water vapor are very tightly

bound to the actual surface, that the intermediate layers of water vapor are

relatively tightly to relatively loosely bound, and that the outermost layers of

water vapor are very loosely bound. (See Figure 2.)

Surface Contamination Modeling . When an overpressure of tritium is added

to the system (i.e., the surface, in this case), a perturbation is introduced to the

system, and Le Chatelier' Principle indicates that the tritium levels in the

mono-molecular layers of water will be shifted to the right; that is,

2H2O + 2D2O + 2T2O

H2O + HDO + D2O + HTO + DTO + T2O .

(9a)

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