Corrosion allowance materials are also viable candidates for radwaste containers, and several countries seem inclined to use them. The principal shortcoming of reliance on corrosion allowance materials is high weight due to the extra metal required to ensure sufficient life. Very heavy containers might present handling problems. Because repositories are very conservatively designed, containers are generally expected to prevent release of radioactive agents for a portion of the total repository life time, and that portion might be shorter than the containers will actually last. Credits for the remaining time are allocated to the fuel, backfill and geologic structure.
Designs vary widely among the many disposal programs now under development.
There is abundant evidence for copper's excellent corrosion resistance. That's certainly long life, but it's not nearly long enough for radwaste burial containers. Under the right geologic conditions, metallic copper can resist corrosion 2000 to 3000 times longer than any repository is expected to survive. Toughness is another important requirement for radwaste burial containers. Containers will have to be rugged enough to withstand the stresses of manufacture, loading, handling and transport to the repository without damage.