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Beyond a million years: Robust radiation shielding for high-level waste Cover

Beyond a million years: Robust radiation shielding for high-level waste

Nukleonika
Volume 70 (2025): Issue 3 (September 2025)
By: Claudio Pescatore  
Open Access
|Aug 2025

Figures & Tables

Fig. 1.

Decay of VHLW from reprocessing 1 metric ton of SF (p. 17 in Ref. [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]).
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]).
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]).
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).
The dose rate 2 cm away from a full-size, unshielded C2 cylinder as a function of time (Source, ANDRA).

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]).
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]).

Decay constants in per-million-year units

Chainλ
U-2381.55 × 10−5
Excess U-2342.82
Np-2370.324

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 ratesC2 VHLW full-sizeC2 VHLW drill core8 PWR SF assembliesCU1 SF drill core
S23816.6–61.941.1
S23424.3–57.336.5
S238 + S23428.8–67.546.7
S23753.548.143.528.2

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)
16.613.1
102.85.5
1002.75.4
10002.34.6

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 ratesC2 VHLW full-sizeC2 VHLW drill core8 PWR SF assembliesCU1 SF drill core
S23842.15.287.466.6
S23449.813.582.761.9
S238 + S23454.317.893.072.2
S23772.266.962.246.9

Dose rate (mSv/h) 2 cm from reference unshielded VHLW and SF at 1 million years [2]

Surface dose ratesC2 VHLW full-sizeC2 VHLW drill core8 PWR SF assembliesCU1 SF drill core
S2380.090.00325.40.82
S2340.180.00683.540.54
S23714.427.454.20.64
Total14.694.4613.142.00
DOI: https://doi.org/10.2478/nuka-2025-0009 | Journal eISSN: 1508-5791 | Journal ISSN: 0029-5922
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Language: English
Page range: 87 - 93
Submitted on: Oct 20, 2024
|
Accepted on: Feb 26, 2025
|
Published on: Aug 22, 2025
Published by: Institute of Nuclear Chemistry and Technology
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year
Keywords:
Geological disposal,
High-level waste,
Million years,
Np-237,
Radiation hazard,
U-238
Related subjects:
Chemistry,
Nuclear chemistry,
Physics,
Astronomy and astrophysics,
Physics, other

© 2025 Claudio Pescatore, published by Institute of Nuclear Chemistry and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

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