Fig. 1.
Decay of VHLW from reprocessing 1 metric ton of SF (p. 17 in Ref. [1]).
Fig. 2.
Decay of activity content of 1 metric ton of Swedish SF (p. 16 in Ref. [3]).
Fig. 3.
External radiation 1 m away from 1 metric ton of Swedish SF (p. 23 in Ref. [3]).
Fig. 4.
Radiological dose rate, in Sv/h, 40 cm from two French HLW drill cores. The C2 drill core is VHLW; the CU1 drill core is SF (p. 533 in Ref. [5]).
Fig. 5.
The dose rate 2 cm away from a full-size, unshielded C2 cylinder as a function of time (Source, ANDRA).
Table 1.
Gamma dose rate (mSv/h) at three distances from a Pollux-8 cask loaded with eight PWR UO2 fuel assemblies, neglecting the shielding of the cask [2]
| Decay time (million years) | Surface (4 cm) | Surface (2 cm extrapolated) |
|---|---|---|
| 1 | 6.6 | 13.1 |
| 10 | 2.8 | 5.5 |
| 100 | 2.7 | 5.4 |
| 1000 | 2.3 | 4.6 |
Table 2.
Dose rate (mSv/h) 2 cm from reference unshielded VHLW and SF at 1 million years [2]
| Surface dose rates | C2 VHLW full-size | C2 VHLW drill core | 8 PWR SF assemblies | CU1 SF drill core |
|---|---|---|---|---|
| S238 | 0.09 | 0.0032 | 5.4 | 0.82 |
| S234 | 0.18 | 0.0068 | 3.54 | 0.54 |
| S237 | 14.42 | 7.45 | 4.2 | 0.64 |
| Total | 14.69 | 4.46 | 13.14 | 2.00 |
Table 4.
Calculated shield thicknesses at 1 million years depending on each nuclear chain and using the proximity criterion. In bold are the required envelope thicknesses for each waste form. These values will decrease in time to reach the values for U-238, reported in italics
| Surface dose rates | C2 VHLW full-size | C2 VHLW drill core | 8 PWR SF assemblies | CU1 SF drill core |
|---|---|---|---|---|
| S238 | 16.6 | – | 61.9 | 41.1 |
| S234 | 24.3 | – | 57.3 | 36.5 |
| S238 + S234 | 28.8 | – | 67.5 | 46.7 |
| S237 | 53.5 | 48.1 | 43.5 | 28.2 |
Table 5.
Calculated shield thicknesses at 1 million years depending on each nuclear chain and using the tolerability criterion. In bold are the required envelope thicknesses for each waste form. These values will decrease in time to reach the calculated for U-238, reported in italics
| Surface dose rates | C2 VHLW full-size | C2 VHLW drill core | 8 PWR SF assemblies | CU1 SF drill core |
|---|---|---|---|---|
| S238 | 42.1 | 5.2 | 87.4 | 66.6 |
| S234 | 49.8 | 13.5 | 82.7 | 61.9 |
| S238 + S234 | 54.3 | 17.8 | 93.0 | 72.2 |
| S237 | 72.2 | 66.9 | 62.2 | 46.9 |
Fig. 6.
Accrued, external dose from drill cores of several kinds of present and future French VHLW after a 10-min exposure, 40 cm from the drill core, and as a function of time (p. 352 in Ref. [9]).