Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Decay constants in per-million-year units
| Chain | λ |
|---|---|
| U-238 | 1.55 × 10−5 |
| Excess U-234 | 2.82 |
| Np-237 | 0.324 |
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 |
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 |
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 |
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 |