TRANSPORTATION OF RADIOACTIVE MATERIALS - Environmentally Conscious Materials Handling - page 231

Each cask used for transportation of used nuclear fuel or high-level waste must
have a certificate of compliance issued by the NRC in accordance with 10 CFR
71, “Packaging and Transportation of Radioactive Material.” The application for
that certificate must contain a package description (10 CFR 71.33), a package
evaluation (10 CFR 71.35), and a quality assurance program description (10
CFR 71.37). The description of the cask needs to be sufficient to allow the NRC
to evaluate whether the cask meets all of the requirements. It includes such
information as construction materials, size, and weight of the cask, fabrication
methods, limits on the composition of the cargo the cask may carry, and means
for heat transfer and dissipation. The described package must undergo evaluations
described in detail in subparts E and F of the code. It must also meet the quality
assurance requirements in subpart H of the code. The NRC has issued a document
(NUREG-1617) titled “Standard Review Plan for Transportation Packages for
Spent Nuclear Fuel” that provides detailed guidance to any company wishing to
obtain a certificate of compliance.
Before issuing a certificate of compliance to a transportation cask for used
nuclear fuel, the NRC must be convinced that the cask will confine the radioactive
material and meet all other regulatory requirements under normal and a set of
hypothetical accident conditions. The regulations say the cask “must be evaluated
by subjecting a specimen or scale model to a specific test, or by another method
of demonstration acceptable to the Commission, as appropriate for the particular
feature being considered” (10 CFR 71.41(a)). Although computer simulation of a
test may technically be allowed, typically the cask is subjected to a series of tests
to determine whether it meets the requirements under four hypothetical accident
conditions. Four tests representing accident conditions are conducted in sequence
on a single cask specimen:
1. Drop test . Drop the cask from 30 feet onto a hard, unyielding surface in
an orientation most likely to damage the cask.
2. Puncture test . Drop the cask from 40 inches on a 6-inch diameter shaft
in an orientation most likely to result in damage.
3. Fire test . Engulf cask fully in a fire at 1475 ◦ F for 30 minutes.
4. Immersion test . Place cask under 3 feet of water for 30 minutes.
Figure 8.8 illustrates the sequence of tests. There is a fifth test, but it is
conducted on a fresh cask rather than one that has been through the first four tests.
The undamaged cask is immersed in water and subjected to pressure equivalent
to water 50 feet deep (10 CFR 71.73).

7 TRANSPORTATION OF OTHER RADIOACTIVE MATERIALS

Although this chapter has focused on transportation of used nuclear fuel and
high-level waste, highly radioactive materials that require special care, many
other forms of radioactive material are routinely shipped in the United States.