A hot-extraction high-vacuum technique, involving mass-spectrographic detection, was used to determine the H content of U. The time-dependences of H evolution from the bulk and of surface contamination were sufficiently different to separate. During the transient temperature portion of the analysis, the H evolution rate was strongly influenced by the solubility of H. The H content which was due to surface contamination was equal to about 0.5ppm[wt]. This limited the lower limit of detection, for bulk H, to 0.05ppm[wt]. Diffusion data for H in U were deduced from the H evolution rates (table 254).

G.L.Powell, J.B.Condon: Analytical Chemistry, 1973, 45[14], 2349-54

 

Table 254

Diffusivity of H in U

 

Temperature (C)

H (ppm[wt])

H Evolution Rate (/s)

D (cm2/s)

441

7.4

2.17 x 10-3

3.2 x 10-6

514

7.4

5.78 x 10-3

8.5 x 10-6

628

7.4

2.56 x 10-2

3.7 x 10-5

742

7.7

4.17 x 10-2

6.1 x 10-5

870

7.7

8.00 x 10-2

1.2 x 10-4

977

7.7

1.10 x 10-1

1.6 x 10-4

514

8.4

5.56 x 10-3

8.1 x 10-6

628

8.4

2.94 x 10-2

4.3 x 10-5

742

9.1

4.26 x 10-2

6.3 x 10-5

870

9.1

7.69 x 10-2

1.1 x 10-4

977

8.8

1.05 x 10-1

1.5 x 10-4